From ronroy at ca.inter.net  Thu Aug  1 16:41:47 2024
From: ronroy at ca.inter.net (ronroy at ca.inter.net)
Date: Thu, 01 Aug 2024 12:41:47 -0400
Subject: [Clayart] Clayart Digest, Vol 104, Issue 19 Manganese
In-Reply-To: <00d201dae29f$d2643170$772c9450$@gmail.com>
References: <mailman.39.1721908805.11792.clayart@lists.clayartforum.com>
 <997546907.671042.1722187201065@mail.yahoo.com>
 <00d201dae29f$d2643170$772c9450$@gmail.com>
Message-ID: <20240801124147.20951fdl533170ej@webmail.ca.inter.net>

I agree mostly with Vince. I suppose it is a stretch but maybe  
possible if clay containing granular manganese was ground underfoot  
enough - perhaps? - the particles could be reduced to the danger  
point. I have been in such studios!

I doubt if the fumes from granular manganese would be much of a  
problem. If you are breathing kiln fumes there are much more serious  
issues.

We have not had a go around on studio air quality for a while. Anyone  
have some something outrageous to say about that?

RR


Quoting Vince Pitelka via Clayart <clayart at lists.clayartforum.com>:

> I'm traveling and haven't followed this thread very close.  As I  
> understand it, in oxidation claybodies, speckles are achieved with  
> granular manganese, while in reduction bodies, they are achieved  
> with iron.  Because the manganese is granular, I have always  
> understood that it poses no threat in handling the raw clay.  Of  
> course, in firing, your kiln needs to be outdoors or equipped with a  
> proper kiln vent system installed and operating.
> - Vince
>
> Vince Pitelka
> Potter, Writer, Teacher
> Chapel Hill, NC
> vincepitelka at gmail.com
> www.vincepitelka.com
> https://chathamartistsguild.org/
>
> -----Original Message-----
> From: Clayart <clayart-bounces at lists.clayartforum.com> On Behalf Of  
> trina281--- via Clayart
> Sent: Sunday, July 28, 2024 10:20 AM
> To: clayart at lists.clayartforum.com
> Cc: trina281 at aol.com
> Subject: Re: [Clayart] Clayart Digest, Vol 104, Issue 19 Manganese
>
>  Coming in late to the discussion. Standard Clay body #112 aren't  
> the speckles Manganese?
>     On Thursday, July 25, 2024 at 08:02:38 AM EDT,  
> clayart-request at lists.clayartforum.com  
> <clayart-request at lists.clayartforum.com> wrote:
>
>  Send Clayart mailing list submissions to
>     clayart at lists.clayartforum.com
>
> To subscribe or unsubscribe via the World Wide Web, visit
>     https://lists.clayartforum.com/mailman/listinfo/clayart
> or, via email, send a message with subject or body 'help' to
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>
> You can reach the person managing the list at
>     clayart-owner at lists.clayartforum.com
>
> When replying, please edit your Subject line so it is more specific  
> than "Re: Contents of Clayart digest..."
>
>
> Today's Topics:
>
>   1. Manganese toxicity - RR (ronroy at ca.inter.net)
>   2. Joining ClayArt? (ronroy at ca.inter.net)
>   3. join clayart instructions (mel jacobson)
>   4. Re: Manganese toxicity - RR (Dragonbelly Ceramics)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Wed, 24 Jul 2024 11:35:38 -0400
> From: ronroy at ca.inter.net
> To: clayart at lists.clayartforum.com
> Subject: [Clayart] Manganese toxicity - RR
> Message-ID: <20240724113538.17063fllw1ml9bgq at webmail.ca.inter.net>
> Content-Type: text/plain; charset=ISO-8859-1; DelSp="Yes";
>     format="flowed"
>
> Below is a letter sent to Mathhew Katz over a month ago by a  
> Canadian potter who pots in a community setting that does not think  
> manganese is a problem. To date he has not responded.
>
> Sent: Friday, June 14, 2024 10:48 AM
> To: Matthew Katz (matt at ceramicmaterialsworkshop.com)
> <matt at ceramicmaterialsworkshop.com>
> Subject: Manganese information from Monona Rossol
>
> Dear Matt:
>
> I am reaching out to you to provide you with some information from  
> Monona Rossol about manganese. Monona is an industrial toxicologist  
> specializing in materials used in the Arts and Theatre, and used to  
> write about toxicology in Clay Times.
>
> In your podcast, "Should I be afraid of manganese", you mentioned  
> that dust is not soluble and that only soluble materials could pass  
> from the lungs to the blood stream.  I found a lot of articles about  
> manganism in miners exposed to dust. Closer to ceramic use, is the  
> case (Hine CH, attached) of a worker who developed manganism in a  
> relatively short time from cleaning up dry glaze powder spills  
> without a mask or proper ventilation.  These sources show that  
> manganese dust does pass into circulation.
>
> Monona was able to shed some more light on this.  According to the  
> SDS, the TLV for manganese dioxide by inhalation in the respirable  
> particle size (fumes and dusts under 10 microns in diameter) is 0.02  
> mg/m3.  She says that this is very low, indicating that manganese  
> dust is very toxic to inhale.
> She also wanted me to share with you the attached published review  
> that concluded that there are multiple environmental sources of  
> manganese that can be additive. This means that the small amount we  
> might be exposed to even if we use PPE and ventilation in ceramics,  
> could be a tipping point over time.
>
> You also mentioned that manganese does not fume until it reaches  
> temperatures well in excess of kiln firing. Were you referring to  
> the boiling point of manganese dioxide? I looked up the melting and  
> boiling points of chrome and copper oxides, and even their melting  
> points are above cone 10.  Yet chrome and copper are known to fume  
> in low firings.
>
> Monona explained that fume generation does not begin at the boiling  
> point of manganese dioxide, but at its melting point (under 1000  
> degrees F) and that fume generation from heating manganese compounds  
> is a risk factor.  Also, interactions with other materials in a  
> glaze may enhance melting and subsequent fuming.
>
> Monona also shared that an earlier sign of manganese toxicity is  
> essential tremor rather than full-blown Parkinson-like symptoms.   
> The majority of welders today have essential tremor attributed to  
> manganese exposure, and early effects are subtle but likely to be  
> irreversible and progressive.
>
> We might hope that people will be diligent in using PPE and damp  
> mopping, or will always vent their kilns effectively, but there will  
> always be those who do not know any better.  I hope you will teach  
> through your courses and podcasts that manganese does confer risks  
> from dust as well as fume inhalation at kiln temperatures.  I have  
> no problem with people using manganese.  I can only hope that they  
> become aware of risks that you can help disseminate.
>
> Thank you for your time.  I would appreciate hearing back from you.
>
> Yours in health,
>
> I have omitted the potters name but she has allowed me to include it  
> if anyone is interested,
>
> RR
>
> ronroy at ca.inter.net
> Web page ronroy.net
>
>
>
>
> ------------------------------
>
> Message: 2
> Date: Wed, 24 Jul 2024 11:37:33 -0400
> From: ronroy at ca.inter.net
> To: clayart at lists.clayartforum.com
> Subject: [Clayart] Joining ClayArt?
> Message-ID: <20240724113733.71201vxos350av25 at webmail.ca.inter.net>
> Content-Type: text/plain; charset=ISO-8859-1; DelSp="Yes";
>     format="flowed"
>
> I can't find the instructions for joining ClayArt - could someone  
> send them to me please - thanks RR
>
>
> Ron Roy
> ronroy at ca.inter.net
> Web page ronroy.net
>
>
>
>
> ------------------------------
>
> Message: 3
> Date: Wed, 24 Jul 2024 13:24:26 -0500
> From: mel jacobson <melpots at mail.com>
> To: "clayart at lists.clayartforum.com" <clayart at lists.clayartforum.com>
> Subject: [Clayart] join clayart instructions
> Message-ID: <0MOPpb-1sbvSB0ywP-00AkJD at smtp.mail.com>
> Content-Type: text/plain; charset="utf-8"
>
>
> https://lists.clayartforum.com/mailman/listinfo/clayart
> www.melpots.com
>
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> ------------------------------
>
> Message: 4
> Date: Wed, 24 Jul 2024 18:17:23 -0400
> From: Dragonbelly Ceramics <lisa at dragonbellyceramics.com>
> To: Clayart international pottery discussion forum
>     <clayart at lists.clayartforum.com>
> Subject: Re: [Clayart] Manganese toxicity - RR
> Message-ID:
>     <CAMxmGNai6fajfO7Ji2fWfpBvwgMCCj0x-GX5aW0=RLahm0PejQ at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> Thank you for sharing this. I do hope Matt responds.
>
> Lisa
>
> On Wed, Jul 24, 2024, 11:35 AM ronroy--- via Clayart <  
> clayart at lists.clayartforum.com> wrote:
>
>> Below is a letter sent to Mathhew Katz over a month ago by a Canadian
>> potter who pots in a community setting that does not think manganese
>> is a problem. To date he has not responded.
>>
>> Sent: Friday, June 14, 2024 10:48 AM
>> To: Matthew Katz (matt at ceramicmaterialsworkshop.com)
>> <matt at ceramicmaterialsworkshop.com>
>> Subject: Manganese information from Monona Rossol
>>
>> Dear Matt:
>>
>> I am reaching out to you to provide you with some information from
>> Monona Rossol about manganese. Monona is an industrial toxicologist
>> specializing in materials used in the Arts and Theatre, and used to
>> write about toxicology in Clay Times.
>>
>> In your podcast, "Should I be afraid of manganese", you mentioned that
>> dust is not soluble and that only soluble materials could pass from
>> the lungs to the blood stream.  I found a lot of articles about
>> manganism in miners exposed to dust. Closer to ceramic use, is the
>> case (Hine CH, attached) of a worker who developed manganism in a
>> relatively short time from cleaning up dry glaze powder spills without
>> a mask or proper ventilation.  These sources show that manganese dust
>> does pass into circulation.
>>
>> Monona was able to shed some more light on this.  According to the
>> SDS, the TLV for manganese dioxide by inhalation in the respirable
>> particle size (fumes and dusts under 10 microns in diameter) is 0.02
>> mg/m3.  She says that this is very low, indicating that manganese dust
>> is very toxic to inhale.
>> She also wanted me to share with you the attached published review
>> that concluded that there are multiple environmental sources of
>> manganese that can be additive. This means that the small amount we
>> might be exposed to even if we use PPE and ventilation in ceramics,
>> could be a tipping point over time.
>>
>> You also mentioned that manganese does not fume until it reaches
>> temperatures well in excess of kiln firing. Were you referring to the
>> boiling point of manganese dioxide? I looked up the melting and
>> boiling points of chrome and copper oxides, and even their melting
>> points are above cone 10.  Yet chrome and copper are known to fume  
>> in low firings.
>>
>> Monona explained that fume generation does not begin at the boiling
>> point of manganese dioxide, but at its melting point (under 1000
>> degrees F) and that fume generation from heating manganese compounds
>> is a risk factor.  Also, interactions with other materials in a glaze
>> may enhance melting and subsequent fuming.
>>
>> Monona also shared that an earlier sign of manganese toxicity is
>> essential tremor rather than full-blown Parkinson-like symptoms.  The
>> majority of welders today have essential tremor attributed to
>> manganese exposure, and early effects are subtle but likely to be  
>> irreversible and progressive.
>>
>> We might hope that people will be diligent in using PPE and damp
>> mopping, or will always vent their kilns effectively, but there will
>> always be those who do not know any better.  I hope you will teach
>> through your courses and podcasts that manganese does confer risks
>> from dust as well as fume inhalation at kiln temperatures.  I have no
>> problem with people using manganese.  I can only hope that they become
>> aware of risks that you can help disseminate.
>>
>> Thank you for your time.  I would appreciate hearing back from you.
>>
>> Yours in health,
>>
>> I have omitted the potters name but she has allowed me to include it
>> if anyone is interested,
>>
>> RR
>>
>> ronroy at ca.inter.net
>> Web page ronroy.net
>>
>>
>>
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> ****************************************
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>



Ron Roy
ronroy at ca.inter.net
Web page ronroy.net



From ronroy at ca.inter.net  Thu Aug  1 16:50:38 2024
From: ronroy at ca.inter.net (ronroy at ca.inter.net)
Date: Thu, 01 Aug 2024 12:50:38 -0400
Subject: [Clayart] Thanks to Ron Roy for helping me reformulate a glaze
In-Reply-To: <CAMxmGNZk+tRkMkwZAJBMwegO0RJB=U7Ec2yZP=DQYewMky2E0g@mail.gmail.com>
References: <CAMxmGNZk+tRkMkwZAJBMwegO0RJB=U7Ec2yZP=DQYewMky2E0g@mail.gmail.com>
Message-ID: <20240801125038.1851527tianjzmqm@webmail.ca.inter.net>

Thanks for posting this Lisa.

Just a few words of caution.

The lemon test will only reveal grossly unstable glazes. This glaze  
will probably still release some copper if in contact with acidic food  
long enough.

One of the clues on how to spot unstable glazes - if the recipe has  
little or no silica. Having enough silica in a glaze (not too much) is  
the key to resistance to acidic food attack.

RR


Quoting Dragonbelly Ceramics via Clayart <clayart at lists.clayartforum.com>:

> I posted a few months back about a glaze that I have long used with weird
> chemistry. Ron was gracious enough to look at it and remind me that not all
> stable glazes exist within a narrow band of chemistry and he gave me an
> alternative formula that (bonus!) used less spodumene and matched the
> original with a slightly higher COE (the origonal was quite low).
>
> I am pleased to say testing it showed me a glaze that completely matches
> the original.
>
> It also passed a 24 hour lemon test.
>
> This is the original formula:
>
> Tom West Green, Cone 6
>
> Ferro Frit 3269: 27
> Gerstley Borate: 15
> Spodumene: 40
> EPK: 18
> Copper Carbonate: 5
> Tin Oxide: 7
>
> COE: 6.1  R20:RO 0.72:0.28 Boron: 0.45
>
> Ron Roy's adjustment:
>
> 3269 .............. 27.0
> Gerstley Borate .... 15.0
> Spodumene ......... 28.0
> Neph Sy ........... 12.0
> EPK ............... 18.0
> Total .............100.0
> + copper carbonate 5
> + Tin oxide 7
>
> COE: 6.6 R20:RO 0.71:0.29 Boron: 0.46
>
> It's a glaze that on iron rich clay when thin is a lovely orange. When
> thick a shimmery metallic green.
>
> On white clay, thin is a mossy green, thick makes a metallic green that
> breaks black.
>
> It also appears to withstand years of exposure to the dishwasher without
> any breakdown in color.
>
> And no one know where the glaze came from. It was in use at a former studio
> I belonged to outside of Boston without any attribution or known history.
>
> Best,
> Lisa
> -------------- next part --------------
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Ron Roy
ronroy at ca.inter.net
Web page ronroy.net



From josephherbert827 at gmail.com  Fri Aug  2 20:04:50 2024
From: josephherbert827 at gmail.com (Joseph Herbert)
Date: Fri, 2 Aug 2024 15:04:50 -0500
Subject: [Clayart] Heavy metals
Message-ID: <CAJGaOv23doZQLiaG95MaDDvRy9-CY+CMPDzvuygBuLPT8vhtgw@mail.gmail.com>

It is a shame that heavy metals are more subtile in their negative effects
than people are in their appreciation of the possibility of damages from
poisoning. Appreciation of time and cumulative effects seem to elude the
normal human mind.

There was a time when victims of black and brown lung were conspicuous
members of society and accepted, routinely, as necessary and unavoidable
results of workplace hazards.  As we know from Alice, the neurological
effects of mercury on hatters was an expected, accepted, and anticipated
consequence of joining the hat trade. People knew that a working life
underground or in a cotton gin, or breathing fumes in a hattery, had
consequences because they say examples frequently.

A further example, in some ways more egregious, but limited in the number
of people impacted, was radium poisoning at the turn of the 20th century. A
delicious combination of heavy metal and radioactivity, radium emulates
calcium in the human body, with devastating effects. Women watch dial
painters were exposed in the workplace; a rich playboy drank radium water;
all suffered early, and gruesome, deaths.

Eventually, the recognition of workplace, home, and environmental hazards
led to governmental efforts to limit or eliminate the hazards and their
effects. The elimination of lead from paint, pottery, and eventually
gasoline, reduced people?s (especially children?s) exposure to that metal
was one of those efforts.

(Earlier in my life I went on an environmental lead soil sampling
expedition at a skeet shooting range in Ohio. Thirty years earlier we could
just have sampled any roadside.)

Ordinary individuals have neither the breadth of experience nor the
subtlety of observation represented by scientific studies of environmental
hazard impacts on a population. For some (to me inexplicable) reason people
value their admittedly uninformed opinion based on ?nothing bad had
happened yet? very limited experience over extensive controlled studies
over multiple large populations.  Perhaps this attitude is maybe somehow
the result of the successful campaigns to remove hazards thus also removing
the evident victims from view.

This same attitude has now applied to vaccines, since we don?t see the
smallpox scared or dead, the polio crippled children, or the childhood
deaths from measles and such. The success of public health efforts have
removed the examples of disease consequences from view so people feel
entitled to ignore our species history of disease.

In the end, a person decides to ignore scientific studies, public health
regulations, and doctor?s advice at their peril. They are free to do that,
but they are not entitled to damage others with their prejudices. Most
often the remedy is left to the civil courts.

So, a studio potter neglects wet cleaning and lives with a layer of
clay/glaze dust on the floor. Ordinary foot traffic suspends the dust
making inhalation inevitable. If there?s no fan or breeze, the respirable
dust may settle over night to start again the next day. And we don?t
complain; their lungs, their business.

Would our response be the same if the negligent potter is teaching in a
group setting that uses talc-containing, low fire white body?  Further,
there is constant foot traffic and mechanical air circulation so the dust
never settles. There is some evidence that very small exposures to asbestos
can result in lung cancers in some people. How do we feel about casual
cleaning here?

There has been argument about the mercury standards for power plant
emissions. Since it is largely impossible to find mercury-free coal to
burn, the lower mercury emission standard results in coal-fired power plant
closures. The argument (by some) is that exposing the population to mercury
is less harmful to society than closing the plants. How should the issue be
decided? Is the population to vote to accept mercury exposure if they also
receive cheaper power? Is it the government?s mandate to protect the health
of the population in general that requires eliminating mercury? From the
70s, the answer has been that we wanted the experience and expertise of
government agency employees to protect us from whatever. Is that changing?

To a certain extent we only know about the dangers of heavy metals because
of government agency efforts. If the mistrust of government afoot in the
world now is intending to carry us back to the world described by Upton
Sinclair in ?The Jungle?, I don?t want to go.

Just rambling

Joe
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From ronroy at ca.inter.net  Sat Aug  3 15:40:54 2024
From: ronroy at ca.inter.net (ronroy at ca.inter.net)
Date: Sat, 03 Aug 2024 11:40:54 -0400
Subject: [Clayart] Heavy metals
In-Reply-To: <CAJGaOv23doZQLiaG95MaDDvRy9-CY+CMPDzvuygBuLPT8vhtgw@mail.gmail.com>
References: <CAJGaOv23doZQLiaG95MaDDvRy9-CY+CMPDzvuygBuLPT8vhtgw@mail.gmail.com>
Message-ID: <20240803114054.13866wgxl37v6s92@webmail.ca.inter.net>

Thanks Joe, food for thought as usual!

Joe is referring to the practice of including lead in gasoline as an  
anti knock agent many years ago. Then they started adding manganese  
for the same reason till they figured out that manganese was a poison  
too and stopped doing that.

I wonder what they use now?

RR

Quoting Joseph Herbert via Clayart <clayart at lists.clayartforum.com>:

> It is a shame that heavy metals are more subtile in their negative effects
> than people are in their appreciation of the possibility of damages from
> poisoning. Appreciation of time and cumulative effects seem to elude the
> normal human mind.
>
> There was a time when victims of black and brown lung were conspicuous
> members of society and accepted, routinely, as necessary and unavoidable
> results of workplace hazards.  As we know from Alice, the neurological
> effects of mercury on hatters was an expected, accepted, and anticipated
> consequence of joining the hat trade. People knew that a working life
> underground or in a cotton gin, or breathing fumes in a hattery, had
> consequences because they say examples frequently.
>
> A further example, in some ways more egregious, but limited in the number
> of people impacted, was radium poisoning at the turn of the 20th century. A
> delicious combination of heavy metal and radioactivity, radium emulates
> calcium in the human body, with devastating effects. Women watch dial
> painters were exposed in the workplace; a rich playboy drank radium water;
> all suffered early, and gruesome, deaths.
>
> Eventually, the recognition of workplace, home, and environmental hazards
> led to governmental efforts to limit or eliminate the hazards and their
> effects. The elimination of lead from paint, pottery, and eventually
> gasoline, reduced people?s (especially children?s) exposure to that metal
> was one of those efforts.
>
> (Earlier in my life I went on an environmental lead soil sampling
> expedition at a skeet shooting range in Ohio. Thirty years earlier we could
> just have sampled any roadside.)
>
> Ordinary individuals have neither the breadth of experience nor the
> subtlety of observation represented by scientific studies of environmental
> hazard impacts on a population. For some (to me inexplicable) reason people
> value their admittedly uninformed opinion based on ?nothing bad had
> happened yet? very limited experience over extensive controlled studies
> over multiple large populations.  Perhaps this attitude is maybe somehow
> the result of the successful campaigns to remove hazards thus also removing
> the evident victims from view.
>
> This same attitude has now applied to vaccines, since we don?t see the
> smallpox scared or dead, the polio crippled children, or the childhood
> deaths from measles and such. The success of public health efforts have
> removed the examples of disease consequences from view so people feel
> entitled to ignore our species history of disease.
>
> In the end, a person decides to ignore scientific studies, public health
> regulations, and doctor?s advice at their peril. They are free to do that,
> but they are not entitled to damage others with their prejudices. Most
> often the remedy is left to the civil courts.
>
> So, a studio potter neglects wet cleaning and lives with a layer of
> clay/glaze dust on the floor. Ordinary foot traffic suspends the dust
> making inhalation inevitable. If there?s no fan or breeze, the respirable
> dust may settle over night to start again the next day. And we don?t
> complain; their lungs, their business.
>
> Would our response be the same if the negligent potter is teaching in a
> group setting that uses talc-containing, low fire white body?  Further,
> there is constant foot traffic and mechanical air circulation so the dust
> never settles. There is some evidence that very small exposures to asbestos
> can result in lung cancers in some people. How do we feel about casual
> cleaning here?
>
> There has been argument about the mercury standards for power plant
> emissions. Since it is largely impossible to find mercury-free coal to
> burn, the lower mercury emission standard results in coal-fired power plant
> closures. The argument (by some) is that exposing the population to mercury
> is less harmful to society than closing the plants. How should the issue be
> decided? Is the population to vote to accept mercury exposure if they also
> receive cheaper power? Is it the government?s mandate to protect the health
> of the population in general that requires eliminating mercury? From the
> 70s, the answer has been that we wanted the experience and expertise of
> government agency employees to protect us from whatever. Is that changing?
>
> To a certain extent we only know about the dangers of heavy metals because
> of government agency efforts. If the mistrust of government afoot in the
> world now is intending to carry us back to the world described by Upton
> Sinclair in ?The Jungle?, I don?t want to go.
>
> Just rambling
>
> Joe
> -------------- next part --------------
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>



Ron Roy
ronroy at ca.inter.net
Web page ronroy.net



From roxhun at gmail.com  Sun Aug  4 18:59:33 2024
From: roxhun at gmail.com (Roxanne Hunnicutt)
Date: Sun, 4 Aug 2024 11:59:33 -0700
Subject: [Clayart] Clayart Digest, Vol 105, Issue 2
In-Reply-To: <mailman.43.1722686403.22368.clayart@lists.clayartforum.com>
References: <mailman.43.1722686403.22368.clayart@lists.clayartforum.com>
Message-ID: <CACeCKqZ=kuxjwQkUH8Kqy_pXR46BjK+VPDhXbENWGsogb3_9tw@mail.gmail.com>

I just want to thank the joseph Herbert and  Ron Roy for the invaluable
discussions.  I am further enlightened every time they speak!

Rox


On Sat, Aug 3, 2024 at 5:02?AM <clayart-request at lists.clayartforum.com>
wrote:

> Send Clayart mailing list submissions to
>         clayart at lists.clayartforum.com
>
> To subscribe or unsubscribe via the World Wide Web, visit
>         https://lists.clayartforum.com/mailman/listinfo/clayart
> or, via email, send a message with subject or body 'help' to
>         clayart-request at lists.clayartforum.com
>
> You can reach the person managing the list at
>         clayart-owner at lists.clayartforum.com
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of Clayart digest..."
>
>
> Today's Topics:
>
>    1. Heavy metals (Joseph Herbert)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Fri, 2 Aug 2024 15:04:50 -0500
> From: Joseph Herbert <josephherbert827 at gmail.com>
> To: clayart at lists.clayartforum.com
> Subject: [Clayart] Heavy metals
> Message-ID:
>         <
> CAJGaOv23doZQLiaG95MaDDvRy9-CY+CMPDzvuygBuLPT8vhtgw at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> It is a shame that heavy metals are more subtile in their negative effects
> than people are in their appreciation of the possibility of damages from
> poisoning. Appreciation of time and cumulative effects seem to elude the
> normal human mind.
>
> There was a time when victims of black and brown lung were conspicuous
> members of society and accepted, routinely, as necessary and unavoidable
> results of workplace hazards.  As we know from Alice, the neurological
> effects of mercury on hatters was an expected, accepted, and anticipated
> consequence of joining the hat trade. People knew that a working life
> underground or in a cotton gin, or breathing fumes in a hattery, had
> consequences because they say examples frequently.
>
> A further example, in some ways more egregious, but limited in the number
> of people impacted, was radium poisoning at the turn of the 20th century. A
> delicious combination of heavy metal and radioactivity, radium emulates
> calcium in the human body, with devastating effects. Women watch dial
> painters were exposed in the workplace; a rich playboy drank radium water;
> all suffered early, and gruesome, deaths.
>
> Eventually, the recognition of workplace, home, and environmental hazards
> led to governmental efforts to limit or eliminate the hazards and their
> effects. The elimination of lead from paint, pottery, and eventually
> gasoline, reduced people?s (especially children?s) exposure to that metal
> was one of those efforts.
>
> (Earlier in my life I went on an environmental lead soil sampling
> expedition at a skeet shooting range in Ohio. Thirty years earlier we could
> just have sampled any roadside.)
>
> Ordinary individuals have neither the breadth of experience nor the
> subtlety of observation represented by scientific studies of environmental
> hazard impacts on a population. For some (to me inexplicable) reason people
> value their admittedly uninformed opinion based on ?nothing bad had
> happened yet? very limited experience over extensive controlled studies
> over multiple large populations.  Perhaps this attitude is maybe somehow
> the result of the successful campaigns to remove hazards thus also removing
> the evident victims from view.
>
> This same attitude has now applied to vaccines, since we don?t see the
> smallpox scared or dead, the polio crippled children, or the childhood
> deaths from measles and such. The success of public health efforts have
> removed the examples of disease consequences from view so people feel
> entitled to ignore our species history of disease.
>
> In the end, a person decides to ignore scientific studies, public health
> regulations, and doctor?s advice at their peril. They are free to do that,
> but they are not entitled to damage others with their prejudices. Most
> often the remedy is left to the civil courts.
>
> So, a studio potter neglects wet cleaning and lives with a layer of
> clay/glaze dust on the floor. Ordinary foot traffic suspends the dust
> making inhalation inevitable. If there?s no fan or breeze, the respirable
> dust may settle over night to start again the next day. And we don?t
> complain; their lungs, their business.
>
> Would our response be the same if the negligent potter is teaching in a
> group setting that uses talc-containing, low fire white body?  Further,
> there is constant foot traffic and mechanical air circulation so the dust
> never settles. There is some evidence that very small exposures to asbestos
> can result in lung cancers in some people. How do we feel about casual
> cleaning here?
>
> There has been argument about the mercury standards for power plant
> emissions. Since it is largely impossible to find mercury-free coal to
> burn, the lower mercury emission standard results in coal-fired power plant
> closures. The argument (by some) is that exposing the population to mercury
> is less harmful to society than closing the plants. How should the issue be
> decided? Is the population to vote to accept mercury exposure if they also
> receive cheaper power? Is it the government?s mandate to protect the health
> of the population in general that requires eliminating mercury? From the
> 70s, the answer has been that we wanted the experience and expertise of
> government agency employees to protect us from whatever. Is that changing?
>
> To a certain extent we only know about the dangers of heavy metals because
> of government agency efforts. If the mistrust of government afoot in the
> world now is intending to carry us back to the world described by Upton
> Sinclair in ?The Jungle?, I don?t want to go.
>
> Just rambling
>
> Joe
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL: <
> https://lists.clayartforum.com/pipermail/clayart/attachments/20240802/0882aae4/attachment.htm
> >
>
> End of Clayart Digest, Vol 105, Issue 2
> ***************************************
>
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From clayart at earthlink.net  Sun Aug  4 20:56:45 2024
From: clayart at earthlink.net (Michael)
Date: Sun, 04 Aug 2024 20:56:45 +0000
Subject: [Clayart] HEAVY METAL
Message-ID: <3535442a-8167-58f3-fd93-3a1c2b413090@earthlink.net>

You mention ( 
a skeet shooting range in Ohio.) were they using lead buckshot?? Lead buckshot was he cause of many birds here in California of dying from lead buckshot found in the prey they ate.
-----Original Message-----
From: <clayart at lists.clayartforum.com>
Sent: Aug 3, 2024 5:01 AM
To: <clayart at lists.clayartforum.com>
Subject: Clayart Digest, Vol 105, Issue 2

Send Clayart mailing list submissions to
clayart at lists.clayartforum.com

To subscribe or unsubscribe via the World Wide Web, visit
https://lists.clayartforum.com/mailman/listinfo/clayart
or, via email, send a message with subject or body 'help' to
clayart-request at lists.clayartforum.com

You can reach the person managing the list at
clayart-owner at lists.clayartforum.com

When replying, please edit your Subject line so it is more specific
than "Re: Contents of Clayart digest..."


Today's Topics:

1. Heavy metals (Joseph Herbert)


----------------------------------------------------------------------

Message: 1
Date: Fri, 2 Aug 2024 15:04:50 -0500
From: Joseph Herbert
To: clayart at lists.clayartforum.com
Subject: [Clayart] Heavy metals
Message-ID:

Content-Type: text/plain; charset="utf-8"

It is a shame that heavy metals are more subtile in their negative effects
than people are in their appreciation of the possibility of damages from
poisoning. Appreciation of time and cumulative effects seem to elude the
normal human mind.

There was a time when victims of black and brown lung were conspicuous
members of society and accepted, routinely, as necessary and unavoidable
results of workplace hazards. As we know from Alice, the neurological
effects of mercury on hatters was an expected, accepted, and anticipated
consequence of joining the hat trade. People knew that a working life
underground or in a cotton gin, or breathing fumes in a hattery, had
consequences because they say examples frequently.

A further example, in some ways more egregious, but limited in the number
of people impacted, was radium poisoning at the turn of the 20th century. A
delicious combination of heavy metal and radioactivity, radium emulates
calcium in the human body, with devastating effects. Women watch dial
painters were exposed in the workplace; a rich playboy drank radium water;
all suffered early, and gruesome, deaths.

Eventually, the recognition of workplace, home, and environmental hazards
led to governmental efforts to limit or eliminate the hazards and their
effects. The elimination of lead from paint, pottery, and eventually
gasoline, reduced people?s (especially children?s) exposure to that metal
was one of those efforts.

(Earlier in my life I went on an environmental lead soil sampling
expedition at a skeet shooting range in Ohio. Thirty years earlier we could
just have sampled any roadside.)

Ordinary individuals have neither the breadth of experience nor the
subtlety of observation represented by scientific studies of environmental
hazard impacts on a population. For some (to me inexplicable) reason people
value their admittedly uninformed opinion based on ?nothing bad had
happened yet? very limited experience over extensive controlled studies
over multiple large populations. Perhaps this attitude is maybe somehow
the result of the successful campaigns to remove hazards thus also removing
the evident victims from view.

This same attitude has now applied to vaccines, since we don?t see the
smallpox scared or dead, the polio crippled children, or the childhood
deaths from measles and such. The success of public health efforts have
removed the examples of disease consequences from view so people feel
entitled to ignore our species history of disease.

In the end, a person decides to ignore scientific studies, public health
regulations, and doctor?s advice at their peril. They are free to do that,
but they are not entitled to damage others with their prejudices. Most
often the remedy is left to the civil courts.

So, a studio potter neglects wet cleaning and lives with a layer of
clay/glaze dust on the floor. Ordinary foot traffic suspends the dust
making inhalation inevitable. If there?s no fan or breeze, the respirable
dust may settle over night to start again the next day. And we don?t
complain; their lungs, their business.

Would our response be the same if the negligent potter is teaching in a
group setting that uses talc-containing, low fire white body? Further,
there is constant foot traffic and mechanical air circulation so the dust
never settles. There is some evidence that very small exposures to asbestos
can result in lung cancers in some people. How do we feel about casual
cleaning here?

There has been argument about the mercury standards for power plant
emissions. Since it is largely impossible to find mercury-free coal to
burn, the lower mercury emission standard results in coal-fired power plant
closures. The argument (by some) is that exposing the population to mercury
is less harmful to society than closing the plants. How should the issue be
decided? Is the population to vote to accept mercury exposure if they also
receive cheaper power? Is it the government?s mandate to protect the health
of the population in general that requires eliminating mercury? From the
70s, the answer has been that we wanted the experience and expertise of
government agency employees to protect us from whatever. Is that changing?

To a certain extent we only know about the dangers of heavy metals because
of government agency efforts. If the mistrust of government afoot in the
world now is intending to carry us back to the world described by Upton
Sinclair in ?The Jungle?, I don?t want to go.

Just rambling

Joe
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End of Clayart Digest, Vol 105, Issue 2
***************************************



From woofpots at hotmail.com  Mon Aug  5 05:51:57 2024
From: woofpots at hotmail.com (David Woof)
Date: Mon, 5 Aug 2024 05:51:57 +0000
Subject: [Clayart] Heavy metals:..... Methyl cyclopenta-dienyl,
 Manganese tri-carbonyl and petroleum distillates.
In-Reply-To: <20240803114054.13866wgxl37v6s92@webmail.ca.inter.net>
References: <CAJGaOv23doZQLiaG95MaDDvRy9-CY+CMPDzvuygBuLPT8vhtgw@mail.gmail.com>
 <20240803114054.13866wgxl37v6s92@webmail.ca.inter.net>
Message-ID: <DM6PR15MB3420C8AC806D3E77D8D1F302C6BD2@DM6PR15MB3420.namprd15.prod.outlook.com>

With the general disinterest in ethics, and declined ability in critical thinking leading to the obvious application of logic. one can always easily find any "truth" one already wishes to believe.

The one curious statistic related to the replacement of lead in gasoline by use of Manganese as the anti-knock remedy is the medically recorded rise in childhood asthma and increase in COPD and other lung disease and breathing disorders since the transition from Lead to Manganese.
Responsible parties already knew of this pulmonary danger because Arc welding rods and flux core welding wire have long carried this health warning on the packaging.

as Ron just said "I wonder what they use now?"

After some digging one finds that manufacturers now are quite closed mouth about octane boosting chemistry including still using benzene rings in some of the formulas, and the heavy metals added.

Claims are made that Ethanol at 10% can increase octane to desired levels.
Yet at the pump we are informed we are getting 8% Ethanol so something other must also be added.

Airplane and Jet fuel is still reputed to use lead, and the auto parts stores offer octane boosters such as products that contain "kerosene, Methyl cyclopenta-dienyl, Manganese tri-carbonyl and petroleum distillates." along with health warnings.

Misneach,

David Woof................................................................................................................................................
*************************************************************************************************
________________________________
From: Clayart <clayart-bounces at lists.clayartforum.com> on behalf of ronroy--- via Clayart <clayart at lists.clayartforum.com>
Sent: Saturday, August 3, 2024 9:40 AM
To: Clayart international pottery discussion forum <clayart at lists.clayartforum.com>
Cc: ronroy at ca.inter.net <ronroy at ca.inter.net>; Joseph Herbert <josephherbert827 at gmail.com>
Subject: Re: [Clayart] Heavy metals

Thanks Joe, food for thought as usual!

Joe is referring to the practice of including lead in gasoline as an
anti knock agent many years ago. Then they started adding manganese
for the same reason till they figured out that manganese was a poison
too and stopped doing that.

I wonder what they use now?

RR

Quoting Joseph Herbert via Clayart <clayart at lists.clayartforum.com>:

> It is a shame that heavy metals are more subtile in their negative effects
> than people are in their appreciation of the possibility of damages from
> poisoning. Appreciation of time and cumulative effects seem to elude the
> normal human mind.
>
> There was a time when victims of black and brown lung were conspicuous
> members of society and accepted, routinely, as necessary and unavoidable
> results of workplace hazards.  As we know from Alice, the neurological
> effects of mercury on hatters was an expected, accepted, and anticipated
> consequence of joining the hat trade. People knew that a working life
> underground or in a cotton gin, or breathing fumes in a hattery, had
> consequences because they say examples frequently.
>
> A further example, in some ways more egregious, but limited in the number
> of people impacted, was radium poisoning at the turn of the 20th century. A
> delicious combination of heavy metal and radioactivity, radium emulates
> calcium in the human body, with devastating effects. Women watch dial
> painters were exposed in the workplace; a rich playboy drank radium water;
> all suffered early, and gruesome, deaths.
>
> Eventually, the recognition of workplace, home, and environmental hazards
> led to governmental efforts to limit or eliminate the hazards and their
> effects. The elimination of lead from paint, pottery, and eventually
> gasoline, reduced people?s (especially children?s) exposure to that metal
> was one of those efforts.
>
> (Earlier in my life I went on an environmental lead soil sampling
> expedition at a skeet shooting range in Ohio. Thirty years earlier we could
> just have sampled any roadside.)
>
> Ordinary individuals have neither the breadth of experience nor the
> subtlety of observation represented by scientific studies of environmental
> hazard impacts on a population. For some (to me inexplicable) reason people
> value their admittedly uninformed opinion based on ?nothing bad had
> happened yet? very limited experience over extensive controlled studies
> over multiple large populations.  Perhaps this attitude is maybe somehow
> the result of the successful campaigns to remove hazards thus also removing
> the evident victims from view.
>
> This same attitude has now applied to vaccines, since we don?t see the
> smallpox scared or dead, the polio crippled children, or the childhood
> deaths from measles and such. The success of public health efforts have
> removed the examples of disease consequences from view so people feel
> entitled to ignore our species history of disease.
>
> In the end, a person decides to ignore scientific studies, public health
> regulations, and doctor?s advice at their peril. They are free to do that,
> but they are not entitled to damage others with their prejudices. Most
> often the remedy is left to the civil courts.
>
> So, a studio potter neglects wet cleaning and lives with a layer of
> clay/glaze dust on the floor. Ordinary foot traffic suspends the dust
> making inhalation inevitable. If there?s no fan or breeze, the respirable
> dust may settle over night to start again the next day. And we don?t
> complain; their lungs, their business.
>
> Would our response be the same if the negligent potter is teaching in a
> group setting that uses talc-containing, low fire white body?  Further,
> there is constant foot traffic and mechanical air circulation so the dust
> never settles. There is some evidence that very small exposures to asbestos
> can result in lung cancers in some people. How do we feel about casual
> cleaning here?
>
> There has been argument about the mercury standards for power plant
> emissions. Since it is largely impossible to find mercury-free coal to
> burn, the lower mercury emission standard results in coal-fired power plant
> closures. The argument (by some) is that exposing the population to mercury
> is less harmful to society than closing the plants. How should the issue be
> decided? Is the population to vote to accept mercury exposure if they also
> receive cheaper power? Is it the government?s mandate to protect the health
> of the population in general that requires eliminating mercury? From the
> 70s, the answer has been that we wanted the experience and expertise of
> government agency employees to protect us from whatever. Is that changing?
>
> To a certain extent we only know about the dangers of heavy metals because
> of government agency efforts. If the mistrust of government afoot in the
> world now is intending to carry us back to the world described by Upton
> Sinclair in ?The Jungle?, I don?t want to go.
>
> Just rambling
>
> Joe
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL:
> <https://lists.clayartforum.com/pipermail/clayart/attachments/20240802/0882aae4/attachment.htm>
>



Ron Roy
ronroy at ca.inter.net
Web page ronroy.net


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From woofpots at hotmail.com  Fri Aug  9 20:22:47 2024
From: woofpots at hotmail.com (David Woof)
Date: Fri, 9 Aug 2024 20:22:47 +0000
Subject: [Clayart] Clayart Digest, Vol 104, Issue 19 Manganese
In-Reply-To: <20240801124147.20951fdl533170ej@webmail.ca.inter.net>
References: <mailman.39.1721908805.11792.clayart@lists.clayartforum.com>
 <997546907.671042.1722187201065@mail.yahoo.com>
 <00d201dae29f$d2643170$772c9450$@gmail.com>
 <20240801124147.20951fdl533170ej@webmail.ca.inter.net>
Message-ID: <DM6PR15MB34206D12910752A5CD87B23AC6BA2@DM6PR15MB3420.namprd15.prod.outlook.com>

Ron, you leave me breathless. (pun intended)

How outrageous these "Studio Dangers" discussions are prone to become, is aptly summed up in this quote from Peter Ditto, social psychologist:
?People are capable of being thoughtful and rational, but our wishes, hopes, fears, and motivations often tip the scales to make us more likely to accept something as true if it supports what we want to believe.??Peter Ditto, social psychologist.

So let us start this "outrageous" discussion with verifiable facts that a group of the Worlds acclaimed and recently passed potters lived long and productive lives using all the materials now feared to extreme measures by fear and fear mongering.

And yes, we know of a few modern ones who died from over exposure to fumes while glazing and firing.  These "modern masters" were not stupid or ignorant by any definition so why then did they succumb early?  Was it denial in that "I know the dangers, but I'll be careful," or denial in that "it won't happen to me"...........(more blanks to fill in please}

But Ron, you, I, we and others have kicked this horse to virtual death and beat the drum to a deafening crescendo. Sill it is obviously falling on deaf ears of some folks.
With so much information readily available, the smart folks can inform/educate themselves to the degree that they can then come with intelligent questions and ideas to discuss the deeper issues of Ceramics chemistry, form, function, artistic expression, and firing methods.......
So since the smart ones already know how to operate a safe studio, and the dummies never will, I have stopped beating my brains about how to help them. Ignorance is a choice, and a bumper sticker aptly advises these afore mentioned folks: "Save the World, Kill Yourself"

I'm sure this rant though in keeping with truth, has Outraged more than a few, How about You?

Next let's talk about the stupidity of outright banning of Talc........

Love to all, including unhappy Trolls and those cowering in fetal positions. Eat your vegies, sing and dance like no one is watching and piss out those toxins you fear......

Misneach,
David Woof..................................................................................................................................................................
***************************************************************************************************
________________________________
From: Clayart <clayart-bounces at lists.clayartforum.com> on behalf of ronroy--- via Clayart <clayart at lists.clayartforum.com>
Sent: Thursday, August 1, 2024 10:41 AM
To: Clayart international pottery discussion forum <clayart at lists.clayartforum.com>
Cc: ronroy at ca.inter.net <ronroy at ca.inter.net>
Subject: Re: [Clayart] Clayart Digest, Vol 104, Issue 19 Manganese

I agree mostly with Vince. I suppose it is a stretch but maybe
possible if clay containing granular manganese was ground underfoot
enough - perhaps? - the particles could be reduced to the danger
point. I have been in such studios!

I doubt if the fumes from granular manganese would be much of a
problem. If you are breathing kiln fumes there are much more serious
issues.

We have not had a go around on studio air quality for a while. Anyone
have some something outrageous to say about that?

RR




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From paul at plrandall.com  Fri Aug  9 23:56:05 2024
From: paul at plrandall.com (Paul Randall)
Date: Fri, 9 Aug 2024 23:56:05 +0000
Subject: [Clayart] Clayart Digest, Vol 104, Issue 19 Manganese
In-Reply-To: <DM6PR15MB34206D12910752A5CD87B23AC6BA2@DM6PR15MB3420.namprd15.prod.outlook.com>
References: <mailman.39.1721908805.11792.clayart@lists.clayartforum.com>
 <997546907.671042.1722187201065@mail.yahoo.com>
 <00d201dae29f$d2643170$772c9450$@gmail.com>
 <20240801124147.20951fdl533170ej@webmail.ca.inter.net>
 <DM6PR15MB34206D12910752A5CD87B23AC6BA2@DM6PR15MB3420.namprd15.prod.outlook.com>
Message-ID: <PH7PR22MB3613C278A48F0D7794F6A38BD9BA2@PH7PR22MB3613.namprd22.prod.outlook.com>

In response to what David Woof has said, I agree.

We can beat this horse to death over and over, with diminishing returns as to the benefit, other than patting ourselves on the back for our ability to rationally discuss atoms.

With sensible precautions, simple cleanliness and diligence, we can overcome 99% of the dangers we discuss. And, at the same time continue to experiment and enhance our art, safely.

The most fruitful discussion in my mind is precaution, cleanliness and diligence.

PLR

Get Outlook for iOS<https://aka.ms/o0ukef>
________________________________
From: Clayart <clayart-bounces at lists.clayartforum.com> on behalf of David Woof via Clayart <clayart at lists.clayartforum.com>
Sent: Friday, August 9, 2024 3:22:47 PM
To: Clayart international pottery discussion forum <clayart at lists.clayartforum.com>
Cc: David Woof <woofpots at hotmail.com>
Subject: Re: [Clayart] Clayart Digest, Vol 104, Issue 19 Manganese

Ron, you leave me breathless. (pun intended)

How outrageous these "Studio Dangers" discussions are prone to become, is aptly summed up in this quote from Peter Ditto, social psychologist:
?People are capable of being thoughtful and rational, but our wishes, hopes, fears, and motivations often tip the scales to make us more likely to accept something as true if it supports what we want to believe.??Peter Ditto, social psychologist.

So let us start this "outrageous" discussion with verifiable facts that a group of the Worlds acclaimed and recently passed potters lived long and productive lives using all the materials now feared to extreme measures by fear and fear mongering.

And yes, we know of a few modern ones who died from over exposure to fumes while glazing and firing.  These "modern masters" were not stupid or ignorant by any definition so why then did they succumb early?  Was it denial in that "I know the dangers, but I'll be careful," or denial in that "it won't happen to me"...........(more blanks to fill in please}

But Ron, you, I, we and others have kicked this horse to virtual death and beat the drum to a deafening crescendo. Sill it is obviously falling on deaf ears of some folks.
With so much information readily available, the smart folks can inform/educate themselves to the degree that they can then come with intelligent questions and ideas to discuss the deeper issues of Ceramics chemistry, form, function, artistic expression, and firing methods.......
So since the smart ones already know how to operate a safe studio, and the dummies never will, I have stopped beating my brains about how to help them. Ignorance is a choice, and a bumper sticker aptly advises these afore mentioned folks: "Save the World, Kill Yourself"

I'm sure this rant though in keeping with truth, has Outraged more than a few, How about You?

Next let's talk about the stupidity of outright banning of Talc........

Love to all, including unhappy Trolls and those cowering in fetal positions. Eat your vegies, sing and dance like no one is watching and piss out those toxins you fear......

Misneach,
David Woof..................................................................................................................................................................
***************************************************************************************************
________________________________
From: Clayart <clayart-bounces at lists.clayartforum.com> on behalf of ronroy--- via Clayart <clayart at lists.clayartforum.com>
Sent: Thursday, August 1, 2024 10:41 AM
To: Clayart international pottery discussion forum <clayart at lists.clayartforum.com>
Cc: ronroy at ca.inter.net <ronroy at ca.inter.net>
Subject: Re: [Clayart] Clayart Digest, Vol 104, Issue 19 Manganese

I agree mostly with Vince. I suppose it is a stretch but maybe
possible if clay containing granular manganese was ground underfoot
enough - perhaps? - the particles could be reduced to the danger
point. I have been in such studios!

I doubt if the fumes from granular manganese would be much of a
problem. If you are breathing kiln fumes there are much more serious
issues.

We have not had a go around on studio air quality for a while. Anyone
have some something outrageous to say about that?

RR




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From terrylazaroff at gmail.com  Wed Aug 14 19:26:18 2024
From: terrylazaroff at gmail.com (Terry Lazaroff)
Date: Wed, 14 Aug 2024 15:26:18 -0400
Subject: [Clayart] (no subject)
Message-ID: <4239B973-EA4E-4B2C-B4BE-76D60FD8C270@hxcore.ol>

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From jeremy.keala.ceramics at gmail.com  Fri Aug 16 16:17:08 2024
From: jeremy.keala.ceramics at gmail.com (Jeremy Keala Ceramics)
Date: Fri, 16 Aug 2024 18:17:08 +0200
Subject: [Clayart] Replacing bentonite
Message-ID: <CA+j6awH6+JyqyeFSiPuM8xgJ89Svzdx_A3XvmHZo-Thhep1Dzg@mail.gmail.com>

Hello,

I?m starting to work on creating a Kuan crackle glaze. My starting recipes
have bentonite in them and I don?t currently don?t have bentonite in my
workshop and would like to keep it that way otherwise I just keep adding
new materials all the time to my list of raw materials.
Would you have any suggestions how to go about replacing bentonite in a
glaze ?
Thanks and all the best,
Jeremy


-- 
*Jeremy Keala Ceramics*
www.jeremykeala.com
Instagram : @jeremy_keala_ceramics
<https://www.instagram.com/jeremy_keala_ceramics/>
+33 (0)6 59 96 92 54
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From woofpots at hotmail.com  Sat Aug 17 04:30:01 2024
From: woofpots at hotmail.com (David Woof)
Date: Sat, 17 Aug 2024 04:30:01 +0000
Subject: [Clayart] Replacing bentonite
In-Reply-To: <CA+j6awH6+JyqyeFSiPuM8xgJ89Svzdx_A3XvmHZo-Thhep1Dzg@mail.gmail.com>
References: <CA+j6awH6+JyqyeFSiPuM8xgJ89Svzdx_A3XvmHZo-Thhep1Dzg@mail.gmail.com>
Message-ID: <MN2SPR01MB00691E17B01D5420DD3DE205C6822@MN2SPR01MB0069.namprd15.prod.outlook.com>

Hi Jeremy,
A typical Kuan Crackle formula contains Neph Sy,  Potash Feldspar,  Silica, and Calcium such as Whiting.
These ingredients alone, mixed into a Glaze slop (slurry) will soon sink to the bottom of the glaze bucket without the addition of a mechanical mineral suspension agent such as Bentonite.
 Bentonite excels as a suspender as well as being the most often addition to effect higher plasticity which supports ability to provide colloidal dispersion, and thus to effect and control the rheology of the glaze slop.
Bentonite also works as a binder to hold the materials together and make a more durable dried adherence to the pot.
Misneach,
David Woof.....................................................................................................................................................................................
**********************************************************************************************************
From: Clayart <clayart-bounces at lists.clayartforum.com> on behalf of Jeremy Keala Ceramics via Clayart <clayart at lists.clayartforum.com>
Sent: Friday, August 16, 2024 10:17 AM
To: clayart at lists.clayartforum.com <clayart at lists.clayartforum.com>
Cc: Jeremy Keala Ceramics <jeremy.keala.ceramics at gmail.com>
Subject: [Clayart] Replacing bentonite

Hello,

I?m starting to work on creating a Kuan crackle glaze. My starting recipes
have bentonite in them and I don?t currently don?t have bentonite in my
workshop and would like to keep it that way otherwise I just keep adding
new materials all the time to my list of raw materials.
Would you have any suggestions how to go about replacing bentonite in a
glaze ?
Thanks and all the best,
Jeremy


--
*Jeremy Keala Ceramics*
www.jeremykeala.com<http://www.jeremykeala.com>
Instagram : @jeremy_keala_ceramics
<https://www.instagram.com/jeremy_keala_ceramics/>
+33 (0)6 59 96 92 54
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From porcelainbyantoinette at gmail.com  Sat Aug 17 19:34:55 2024
From: porcelainbyantoinette at gmail.com (Antoinette Badenhorst)
Date: Sat, 17 Aug 2024 14:34:55 -0500
Subject: [Clayart] Replacing bentonite
In-Reply-To: <CA+j6awH6+JyqyeFSiPuM8xgJ89Svzdx_A3XvmHZo-Thhep1Dzg@mail.gmail.com>
References: <CA+j6awH6+JyqyeFSiPuM8xgJ89Svzdx_A3XvmHZo-Thhep1Dzg@mail.gmail.com>
Message-ID: <CAH3_PmE0Vjy7bSP1fE=dQt6Dzeen0fVQZrAurHmWNbn2b=7sqg@mail.gmail.com>

Jeremy I agree with David, however, I use Macaloid. It is clear and does
not affect the clay or glaze in any other way than helping with suspension,
workability in clay and as a binder. It is one of the "staples" in my
studio. I use it in anything that tends to settle in a bucket. I use Epsom
salts in rare situations and only when I need immediate effects.

Antoinette Badenhorst



*PorcelainByAntoinette   <https://www.porcelainbyantoinette.com/#/>*

*TeachinArt* <https://www.teachinart.com/antoinette-badenhorst.html>

*International Academy of Ceramics*
<https://www.aic-iac.org/en/member/antoinette-badenhorst/>

*Mississippi Arts Commission
<https://arts.ms.gov/artist/antoinette-badenhorst/>*

*MSClayworks <https://www.msclayworks.com/#/>*




On Fri, Aug 16, 2024 at 8:37?PM Jeremy Keala Ceramics via Clayart <
clayart at lists.clayartforum.com> wrote:

> Hello,
>
> I?m starting to work on creating a Kuan crackle glaze. My starting recipes
> have bentonite in them and I don?t currently don?t have bentonite in my
> workshop and would like to keep it that way otherwise I just keep adding
> new materials all the time to my list of raw materials.
> Would you have any suggestions how to go about replacing bentonite in a
> glaze ?
> Thanks and all the best,
> Jeremy
>
>
> --
> *Jeremy Keala Ceramics*
> www.jeremykeala.com
> Instagram : @jeremy_keala_ceramics
> <https://www.instagram.com/jeremy_keala_ceramics/>
> +33 (0)6 59 96 92 54
> -------------- next part --------------
> An HTML attachment was scrubbed...
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> https://lists.clayartforum.com/pipermail/clayart/attachments/20240816/8aef6a27/attachment.htm
> >
>
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From carol at knighten.org  Sun Aug 18 02:45:05 2024
From: carol at knighten.org (carol at knighten.org)
Date: Sat, 17 Aug 2024 19:45:05 -0700
Subject: [Clayart] recent work - a different sort of leaf print
Message-ID: <26305.24625.418558.159407@Hera.knighten.org>

Hi -

A different sort of leaf print

https://carol.knighten.org/2024-GlazeTests/2024-08-18-leafEdge/

Carol


-- 
============================
    Carol Marians       
    (541) 296-4528
  carol at knighten.org 
http://carol.knighten.org
============================



From vincepitelka at gmail.com  Mon Aug 19 00:01:48 2024
From: vincepitelka at gmail.com (vincepitelka at gmail.com)
Date: Sun, 18 Aug 2024 17:01:48 -0700
Subject: [Clayart] recent work - a different sort of leaf print
In-Reply-To: <26305.24625.418558.159407@Hera.knighten.org>
References: <26305.24625.418558.159407@Hera.knighten.org>
Message-ID: <00ce01daf1ca$fda8b1f0$f8fa15d0$@gmail.com>

Hi Carol - 
This is lovely.  I like the "ghost-image" of the leaf veins, almost like an
X-ray.
- Vince

Vince Pitelka
Potter, Writer, Teacher
Chapel Hill, NC
vincepitelka at gmail.com 
www.vincepitelka.com 
https://chathamartistsguild.org/ 

-----Original Message-----
From: Clayart <clayart-bounces at lists.clayartforum.com> On Behalf Of carol
via Clayart
Sent: Saturday, August 17, 2024 7:45 PM
To: clayart at lists.clayartforum.com
Cc: carol at knighten.org
Subject: [Clayart] recent work - a different sort of leaf print

Hi -

A different sort of leaf print

https://carol.knighten.org/2024-GlazeTests/2024-08-18-leafEdge/

Carol


-- 
============================
    Carol Marians       
    (541) 296-4528
  carol at knighten.org 
http://carol.knighten.org
============================




From carol at knighten.org  Mon Aug 19 02:44:37 2024
From: carol at knighten.org (carol at knighten.org)
Date: Sun, 18 Aug 2024 19:44:37 -0700
Subject: [Clayart] recent work - a multicolored leaf
Message-ID: <26306.45461.252901.527108@Hera.knighten.org>

Hi -

A multi-colored leaf print

https://carol.knighten.org/2024-GlazeTests/2024-08-20-leaf-again/

Carol


-- 
============================
    Carol Marians       
    (541) 296-4528
  carol at knighten.org 
http://carol.knighten.org
============================



From terrylazaroff at gmail.com  Mon Aug 19 15:49:07 2024
From: terrylazaroff at gmail.com (Terry Lazaroff)
Date: Mon, 19 Aug 2024 15:49:07 +0000
Subject: [Clayart] recent work - a multicolored leaf
In-Reply-To: <26306.45461.252901.527108@Hera.knighten.org>
References: <26306.45461.252901.527108@Hera.knighten.org>
Message-ID: <YT2PR01MB8933F6F81DECAD45C1E1F3D7F18C2@YT2PR01MB8933.CANPRD01.PROD.OUTLOOK.COM>

Hello Carol;

This leaf image is awesome.   Well done.

Terry
________________________________
From: Clayart <clayart-bounces at lists.clayartforum.com> on behalf of carol via Clayart <clayart at lists.clayartforum.com>
Sent: Sunday, August 18, 2024 10:44 PM
To: clayart at lists.clayartforum.com <clayart at lists.clayartforum.com>
Cc: carol at knighten.org <carol at knighten.org>
Subject: [Clayart] recent work - a multicolored leaf

Hi -

A multi-colored leaf print

https://carol.knighten.org/2024-GlazeTests/2024-08-20-leaf-again/

Carol


--
============================
    Carol Marians
    (541) 296-4528
  carol at knighten.org
http://carol.knighten.org
============================


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From pecanupp at gmail.com  Mon Aug 19 16:28:10 2024
From: pecanupp at gmail.com (Phyllis Canupp)
Date: Mon, 19 Aug 2024 12:28:10 -0400
Subject: [Clayart] recent work - a multicolored leaf
In-Reply-To: <26306.45461.252901.527108@Hera.knighten.org>
References: <26306.45461.252901.527108@Hera.knighten.org>
Message-ID: <CAD8zgU7oo+kauUyKf7Z=JsLiPJwkkij9xUYLDKZBtzWpg1MOHA@mail.gmail.com>

I love this one the most. I look at all your leaf postings. Looks like
honey and tree sap!
Congratulations!

On Mon, Aug 19, 2024 at 4:23?AM carol via Clayart <
clayart at lists.clayartforum.com> wrote:

> Hi -
>
> A multi-colored leaf print
>
> https://carol.knighten.org/2024-GlazeTests/2024-08-20-leaf-again/
>
> Carol
>
>
> --
> ============================
>     Carol Marians
>     (541) 296-4528
>   carol at knighten.org
> http://carol.knighten.org
> ============================
>
>
>
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From carol at knighten.org  Tue Aug 20 03:56:05 2024
From: carol at knighten.org (carol at knighten.org)
Date: Mon, 19 Aug 2024 20:56:05 -0700
Subject: [Clayart] recent work - increasing alumina
Message-ID: <26308.5077.827400.212586@Hera.knighten.org>

Hi -

The effect of increased alumina on a cobalt glaze:

https://carol.knighten.org/2024-GlazeTests/2024-08-21-alumina/


Carol


-- 
============================
    Carol Marians       
    (541) 296-4528
  carol at knighten.org 
http://carol.knighten.org
============================



From vincepitelka at gmail.com  Tue Aug 20 22:31:24 2024
From: vincepitelka at gmail.com (vincepitelka at gmail.com)
Date: Tue, 20 Aug 2024 15:31:24 -0700
Subject: [Clayart] recent work - increasing alumina
In-Reply-To: <26308.5077.827400.212586@Hera.knighten.org>
References: <26308.5077.827400.212586@Hera.knighten.org>
Message-ID: <00b801daf350$b0eaebd0$12c0c370$@gmail.com>

Hi Carol - 
Wow!  Now there's a blue I could live with!  The inside of the bowl in the
first image is the real stunner, and what strikes me most is the multiple
shades of blue in the crystals contrasting beautifully with the dark cobalt
blue background.  As Bill Schrann will affirm, this is the kind of contrast
that the macrocrystal potters strive for.  
- Vince

Vince Pitelka
Potter, Writer, Teacher
Chapel Hill, NC
vincepitelka at gmail.com 
www.vincepitelka.com 
https://chathamartistsguild.org/ 

-----Original Message-----
From: Clayart <clayart-bounces at lists.clayartforum.com> On Behalf Of carol
via Clayart
Sent: Monday, August 19, 2024 8:56 PM
To: clayart at lists.clayartforum.com
Cc: carol at knighten.org
Subject: [Clayart] recent work - increasing alumina

Hi -

The effect of increased alumina on a cobalt glaze:

https://carol.knighten.org/2024-GlazeTests/2024-08-21-alumina/


Carol


-- 
============================
    Carol Marians       
    (541) 296-4528
  carol at knighten.org 
http://carol.knighten.org
============================




From woofpots at hotmail.com  Wed Aug 21 00:21:56 2024
From: woofpots at hotmail.com (David Woof)
Date: Wed, 21 Aug 2024 00:21:56 +0000
Subject: [Clayart] Replacing bentonite
In-Reply-To: <CA+j6awH6+JyqyeFSiPuM8xgJ89Svzdx_A3XvmHZo-Thhep1Dzg@mail.gmail.com>
References: <CA+j6awH6+JyqyeFSiPuM8xgJ89Svzdx_A3XvmHZo-Thhep1Dzg@mail.gmail.com>
Message-ID: <BN8PR15MB34104B3BA12BE277695EC00EC68D2@BN8PR15MB3410.namprd15.prod.outlook.com>

Hi Jeremy,
You asked for a replacement for Bentonite.  Perhaps we assumed you knew the mineral qualities of the materials you have available to know you could not just whip up a batch of what Bentonite could be replaced with.  So our answers asked you to discern that there is no simple one material substitute.
Macaloid and Bentonites are unique materials that cannot be substituted singly or in combinations of raw materials you would likely have.  This also requires understanding the intrinsic characters of each mineral and the combination effects involved.

We could have no doubt wasted your time telling you to take a high plasticity synthesized Ball clay, reduce the original recipe amounts of feldspar and silica and adjust the recipe ratios to accommodate these additions back to the original Empirical.

Then add enough CMC gum as a physical "mechanical" suspender, adequate Hopefulness, and Sodium Silicate to deflocculate the glaze slop.    Then if you've worked the Math correctly to arrive at a workable materials ratio... you would still have to learn how to apply a deflocculated glaze slop because the slop rheology will be way off of what most potters who use flocculated glaze slops are familiar with.
And no doubt you would lose the Kuan Crackle glaze effect because you have created a new Glaze. which might be an attractive glaze but not Kuan you'd hoped for.
So If I gave you the adjusted amounts for this substitution most likely the results wouldn't please.

********So back to Bentonite or Macaloid.

Misneach,

David Woof.....................................................................................................................................................................
****************************************************************************************************.
________________________________
From: Clayart <clayart-bounces at lists.clayartforum.com> on behalf of Jeremy Keala Ceramics via Clayart <clayart at lists.clayartforum.com>
Sent: Friday, August 16, 2024 10:17 AM
To: clayart at lists.clayartforum.com <clayart at lists.clayartforum.com>
Cc: Jeremy Keala Ceramics <jeremy.keala.ceramics at gmail.com>
Subject: [Clayart] Replacing bentonite

Hello,

I?m starting to work on creating a Kuan crackle glaze. My starting recipes
have bentonite in them and I don?t currently don?t have bentonite in my
workshop and would like to keep it that way otherwise I just keep adding
new materials all the time to my list of raw materials.
Would you have any suggestions how to go about replacing bentonite in a
glaze ?
Thanks and all the best,
Jeremy


--
*Jeremy Keala Ceramics*
www.jeremykeala.com<http://www.jeremykeala.com>
Instagram : @jeremy_keala_ceramics
<https://www.instagram.com/jeremy_keala_ceramics/>
+33 (0)6 59 96 92 54
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From mary8252 at gmail.com  Wed Aug 21 01:30:50 2024
From: mary8252 at gmail.com (Mary Winter)
Date: Tue, 20 Aug 2024 20:30:50 -0500
Subject: [Clayart] Replacing bentonite
In-Reply-To: <BN8PR15MB34104B3BA12BE277695EC00EC68D2@BN8PR15MB3410.namprd15.prod.outlook.com>
References: <CA+j6awH6+JyqyeFSiPuM8xgJ89Svzdx_A3XvmHZo-Thhep1Dzg@mail.gmail.com>
 <BN8PR15MB34104B3BA12BE277695EC00EC68D2@BN8PR15MB3410.namprd15.prod.outlook.com>
Message-ID: <CALXb=+vAOJM-fmbRRkLLUpTwuFq+BGeJo5AXh333C-SBPTH+WA@mail.gmail.com>

Jeremy you can get 5 pounds of bentonite from US Pigment for $10. You might
consider this.

Mary

On Tue, Aug 20, 2024 at 8:26?PM David Woof via Clayart <
clayart at lists.clayartforum.com> wrote:

> Hi Jeremy,
> You asked for a replacement for Bentonite.  Perhaps we assumed you knew
> the mineral qualities of the materials you have available to know you could
> not just whip up a batch of what Bentonite could be replaced with.  So our
> answers asked you to discern that there is no simple one material
> substitute.
> Macaloid and Bentonites are unique materials that cannot be substituted
> singly or in combinations of raw materials you would likely have.  This
> also requires understanding the intrinsic characters of each mineral and
> the combination effects involved.
>
> We could have no doubt wasted your time telling you to take a high
> plasticity synthesized Ball clay, reduce the original recipe amounts of
> feldspar and silica and adjust the recipe ratios to accommodate these
> additions back to the original Empirical.
>
> Then add enough CMC gum as a physical "mechanical" suspender, adequate
> Hopefulness, and Sodium Silicate to deflocculate the glaze slop.    Then if
> you've worked the Math correctly to arrive at a workable materials ratio...
> you would still have to learn how to apply a deflocculated glaze slop
> because the slop rheology will be way off of what most potters who use
> flocculated glaze slops are familiar with.
> And no doubt you would lose the Kuan Crackle glaze effect because you have
> created a new Glaze. which might be an attractive glaze but not Kuan you'd
> hoped for.
> So If I gave you the adjusted amounts for this substitution most likely
> the results wouldn't please.
>
> ********So back to Bentonite or Macaloid.
>
> Misneach,
>
> David
> Woof.....................................................................................................................................................................
>
> ****************************************************************************************************.
> ________________________________
> From: Clayart <clayart-bounces at lists.clayartforum.com> on behalf of
> Jeremy Keala Ceramics via Clayart <clayart at lists.clayartforum.com>
> Sent: Friday, August 16, 2024 10:17 AM
> To: clayart at lists.clayartforum.com <clayart at lists.clayartforum.com>
> Cc: Jeremy Keala Ceramics <jeremy.keala.ceramics at gmail.com>
> Subject: [Clayart] Replacing bentonite
>
> Hello,
>
> I?m starting to work on creating a Kuan crackle glaze. My starting recipes
> have bentonite in them and I don?t currently don?t have bentonite in my
> workshop and would like to keep it that way otherwise I just keep adding
> new materials all the time to my list of raw materials.
> Would you have any suggestions how to go about replacing bentonite in a
> glaze ?
> Thanks and all the best,
> Jeremy
>
>
> --
> *Jeremy Keala Ceramics*
> www.jeremykeala.com<http://www.jeremykeala.com>
> Instagram : @jeremy_keala_ceramics
> <https://www.instagram.com/jeremy_keala_ceramics/>
> +33 (0)6 59 96 92 54
> -------------- next part --------------
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> >
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From terrylazaroff at gmail.com  Wed Aug 21 05:19:37 2024
From: terrylazaroff at gmail.com (Terry Lazaroff)
Date: Wed, 21 Aug 2024 05:19:37 +0000
Subject: [Clayart] recent work - increasing alumina
In-Reply-To: <00b801daf350$b0eaebd0$12c0c370$@gmail.com>
References: <26308.5077.827400.212586@Hera.knighten.org>
 <00b801daf350$b0eaebd0$12c0c370$@gmail.com>
Message-ID: <YT2PR01MB893346643A6B5A0FDF7EF7A5F18E2@YT2PR01MB8933.CANPRD01.PROD.OUTLOOK.COM>

Carol;

Well done!

Yes;   Its  a racer.

Terry



________________________________
From: Clayart <clayart-bounces at lists.clayartforum.com> on behalf of Vince Pitelka via Clayart <clayart at lists.clayartforum.com>
Sent: Tuesday, August 20, 2024 6:31 PM
To: 'Carol Marians' <carol at knighten.org>; 'Clayart international pottery discussion forum' <clayart at lists.clayartforum.com>
Cc: vincepitelka at gmail.com <vincepitelka at gmail.com>
Subject: Re: [Clayart] recent work - increasing alumina

Hi Carol -
Wow!  Now there's a blue I could live with!  The inside of the bowl in the
first image is the real stunner, and what strikes me most is the multiple
shades of blue in the crystals contrasting beautifully with the dark cobalt
blue background.  As Bill Schrann will affirm, this is the kind of contrast
that the macrocrystal potters strive for.
- Vince

Vince Pitelka
Potter, Writer, Teacher
Chapel Hill, NC
vincepitelka at gmail.com
www.vincepitelka.com<http://www.vincepitelka.com>
https://chathamartistsguild.org/

-----Original Message-----
From: Clayart <clayart-bounces at lists.clayartforum.com> On Behalf Of carol
via Clayart
Sent: Monday, August 19, 2024 8:56 PM
To: clayart at lists.clayartforum.com
Cc: carol at knighten.org
Subject: [Clayart] recent work - increasing alumina

Hi -

The effect of increased alumina on a cobalt glaze:

https://carol.knighten.org/2024-GlazeTests/2024-08-21-alumina/


Carol


--
============================
    Carol Marians
    (541) 296-4528
  carol at knighten.org
http://carol.knighten.org
============================



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From carol at knighten.org  Wed Aug 21 18:23:59 2024
From: carol at knighten.org (carol at knighten.org)
Date: Wed, 21 Aug 2024 11:23:59 -0700
Subject: [Clayart] recent work - iron green
Message-ID: <26310.12479.774330.642518@Hera.knighten.org>

Hi -

iron green in oxidation:

https://carol.knighten.org/2024-GlazeTests/2024-08-23-ironColors/


Carol


-- 
============================
    Carol Marians       
    (541) 296-4528
  carol at knighten.org 
http://carol.knighten.org
============================



From carol at knighten.org  Thu Aug 22 03:03:55 2024
From: carol at knighten.org (carol at knighten.org)
Date: Wed, 21 Aug 2024 20:03:55 -0700
Subject: [Clayart] recent work - increasing alumina
In-Reply-To: <00b801daf350$b0eaebd0$12c0c370$@gmail.com>
References: <26308.5077.827400.212586@Hera.knighten.org>
 <00b801daf350$b0eaebd0$12c0c370$@gmail.com>
Message-ID: <26310.43675.662284.387447@Hera.knighten.org>

Hi Vince -

Thanks for kind words -

If one tests sufficient glazes in a small region of glaze space, one is bound
to happen upon interesting things.  I've tested over two dozen glazes near
that glaze, its been an amazing and wonderful odyssey.

Carol


vincepitelka at gmail.com writes:
 > Hi Carol - 
 > Wow!  Now there's a blue I could live with!  The inside of the bowl in the
 > first image is the real stunner, and what strikes me most is the multiple
 > shades of blue in the crystals contrasting beautifully with the dark cobalt
 > blue background.  As Bill Schrann will affirm, this is the kind of contrast
 > that the macrocrystal potters strive for.  
 > - Vince
 > 
 > Vince Pitelka
 > Potter, Writer, Teacher
 > Chapel Hill, NC
 > vincepitelka at gmail.com 
 > www.vincepitelka.com 
 > https://chathamartistsguild.org/ 
 > 
 > -----Original Message-----
 > From: Clayart <clayart-bounces at lists.clayartforum.com> On Behalf Of carol
 > via Clayart
 > Sent: Monday, August 19, 2024 8:56 PM
 > To: clayart at lists.clayartforum.com
 > Cc: carol at knighten.org
 > Subject: [Clayart] recent work - increasing alumina
 > 
 > Hi -
 > 
 > The effect of increased alumina on a cobalt glaze:
 > 
 > https://carol.knighten.org/2024-GlazeTests/2024-08-21-alumina/
 > 

-- 
============================
    Carol Marians       
    (541) 296-4528
  carol at knighten.org 
http://carol.knighten.org
============================



From ronroy at ca.inter.net  Thu Aug 22 18:50:12 2024
From: ronroy at ca.inter.net (ronroy at ca.inter.net)
Date: Thu, 22 Aug 2024 14:50:12 -0400
Subject: [Clayart] Replacing bentonite
In-Reply-To: <CA+j6awH6+JyqyeFSiPuM8xgJ89Svzdx_A3XvmHZo-Thhep1Dzg@mail.gmail.com>
References: <CA+j6awH6+JyqyeFSiPuM8xgJ89Svzdx_A3XvmHZo-Thhep1Dzg@mail.gmail.com>
Message-ID: <20240822145012.20785awwlqsqv2hw@webmail.ca.inter.net>

Hi Jeremy,

My general rule about bentonite is:

If a glaze has less than 10% kaolin bentonite may be needed to keep  
that glaze in suspension long enough while glazing pots. That?s  
because kaolins are not very good suspenders especially if there is  
any deflocculation going on.

First I would swap out the kaolin and replace with ball clay using  
calculation of course. If that would not work then add 2% bentonite.

There are advantages to both ball clay and bentonite. They both add a  
toughness to dried glaze (anti powdering) and glazes dry slower after  
application.

There are many published glazes that do have some bentonite but may  
not need it. Yours may be one of those. If you send me the recipe I  
can give you my opinion.

In some cases a glaze may be hard panning because of the local water  
or perhaps a material that is leaking sodium into a glaze over time -  
like neph sy.

In the first case using a pure form of water will correct the problem.  
In the second case adding some flocculant like Epsom salts will work -  
use very little Epsom - anyone who wants my technique for finding out  
how much to use just ask.

Anyway - happy to give you an opinion.

RR



Quoting Jeremy Keala Ceramics via Clayart <clayart at lists.clayartforum.com>:

> Hello,
>
> I?m starting to work on creating a Kuan crackle glaze. My starting recipes
> have bentonite in them and I don?t currently don?t have bentonite in my
> workshop and would like to keep it that way otherwise I just keep adding
> new materials all the time to my list of raw materials.
> Would you have any suggestions how to go about replacing bentonite in a
> glaze ?
> Thanks and all the best,
> Jeremy
>
>
> --
> *Jeremy Keala Ceramics*
> www.jeremykeala.com
> Instagram : @jeremy_keala_ceramics
> <https://www.instagram.com/jeremy_keala_ceramics/>
> +33 (0)6 59 96 92 54
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL:  
> <https://lists.clayartforum.com/pipermail/clayart/attachments/20240816/8aef6a27/attachment.htm>
>



Ron Roy
ronroy at ca.inter.net
Web page ronroy.net



From woofpots at hotmail.com  Fri Aug 23 00:58:21 2024
From: woofpots at hotmail.com (David Woof)
Date: Fri, 23 Aug 2024 00:58:21 +0000
Subject: [Clayart] Replacing bentonite
In-Reply-To: <CALXb=+vAOJM-fmbRRkLLUpTwuFq+BGeJo5AXh333C-SBPTH+WA@mail.gmail.com>
References: <CA+j6awH6+JyqyeFSiPuM8xgJ89Svzdx_A3XvmHZo-Thhep1Dzg@mail.gmail.com>
 <BN8PR15MB34104B3BA12BE277695EC00EC68D2@BN8PR15MB3410.namprd15.prod.outlook.com>
 <CALXb=+vAOJM-fmbRRkLLUpTwuFq+BGeJo5AXh333C-SBPTH+WA@mail.gmail.com>
Message-ID: <DM6PR15MB342084C2F5661080CEBCE4F6C68F2@DM6PR15MB3420.namprd15.prod.outlook.com>

Hi Mary,
Several of us now have responded to Jeremy's request for information re replacing Bentonite.
I would consider it right and proper to hear back from him as to how his concerns are being resolved.

Of course I'm not losing sleep, but the question has flitted through my musings that a growing number of folks may be not familiar with the long-time spirit of the traditional Clayart forum where unpaid experienced potters and studio artists give well considered information to those asking because of our dedication to the Craft.

It is appreciated when the inquiring person responds to the conversation with a thank you, a request for further clarification, or of a sharing of their experience, which then is a return benefit for all.

This goes to the spirit of Clayart that we are all here as students as well as teachers.

In this way the learning experience of the Craft accumulates and never ceases as many continue to support the appreciation of Clayart value that keeps this valuable resource alive.

Misneach,

David Woof...............................................................................................................................................................
***************************************************************************************************
________________________________
From: Clayart <clayart-bounces at lists.clayartforum.com> on behalf of Mary Winter via Clayart <clayart at lists.clayartforum.com>
Sent: Tuesday, August 20, 2024 7:30 PM
To: Clayart international pottery discussion forum <clayart at lists.clayartforum.com>
Cc: Mary Winter <mary8252 at gmail.com>
Subject: Re: [Clayart] Replacing bentonite

Jeremy you can get 5 pounds of bentonite from US Pigment for $10. You might
consider this.

Mary

On Tue, Aug 20, 2024 at 8:26?PM David Woof via Clayart <
clayart at lists.clayartforum.com> wrote:

> Hi Jeremy,
> You asked for a replacement for Bentonite.  Perhaps we assumed you knew
> the mineral qualities of the materials you have available to know you could
> not just whip up a batch of what Bentonite could be replaced with.  So our
> answers asked you to discern that there is no simple one material
> substitute.
> Macaloid and Bentonites are unique materials that cannot be substituted
> singly or in combinations of raw materials you would likely have.  This
> also requires understanding the intrinsic characters of each mineral and
> the combination effects involved.
>
> We could have no doubt wasted your time telling you to take a high
> plasticity synthesized Ball clay, reduce the original recipe amounts of
> feldspar and silica and adjust the recipe ratios to accommodate these
> additions back to the original Empirical.
>
> Then add enough CMC gum as a physical "mechanical" suspender, adequate
> Hopefulness, and Sodium Silicate to deflocculate the glaze slop.    Then if
> you've worked the Math correctly to arrive at a workable materials ratio...
> you would still have to learn how to apply a deflocculated glaze slop
> because the slop rheology will be way off of what most potters who use
> flocculated glaze slops are familiar with.
> And no doubt you would lose the Kuan Crackle glaze effect because you have
> created a new Glaze. which might be an attractive glaze but not Kuan you'd
> hoped for.
> So If I gave you the adjusted amounts for this substitution most likely
> the results wouldn't please.
>
> ********So back to Bentonite or Macaloid.
>
> Misneach,
>
> David
> Woof.....................................................................................................................................................................
>
> ****************************************************************************************************.
> ________________________________
> From: Clayart <clayart-bounces at lists.clayartforum.com> on behalf of
> Jeremy Keala Ceramics via Clayart <clayart at lists.clayartforum.com>
> Sent: Friday, August 16, 2024 10:17 AM
> To: clayart at lists.clayartforum.com <clayart at lists.clayartforum.com>
> Cc: Jeremy Keala Ceramics <jeremy.keala.ceramics at gmail.com>
> Subject: [Clayart] Replacing bentonite
>
> Hello,
>
> I?m starting to work on creating a Kuan crackle glaze. My starting recipes
> have bentonite in them and I don?t currently don?t have bentonite in my
> workshop and would like to keep it that way otherwise I just keep adding
> new materials all the time to my list of raw materials.
> Would you have any suggestions how to go about replacing bentonite in a
> glaze ?
> Thanks and all the best,
> Jeremy
>
>
> --
> *Jeremy Keala Ceramics*
> www.jeremykeala.com<http://www.jeremykeala.com>
> Instagram : @jeremy_keala_ceramics
> <https://www.instagram.com/jeremy_keala_ceramics/>
> +33 (0)6 59 96 92 54
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL: <
> https://lists.clayartforum.com/pipermail/clayart/attachments/20240816/8aef6a27/attachment.htm
> >
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL: <
> https://lists.clayartforum.com/pipermail/clayart/attachments/20240821/89319316/attachment.htm
> >
>
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From jeremy.keala.ceramics at gmail.com  Fri Aug 23 14:20:48 2024
From: jeremy.keala.ceramics at gmail.com (Jeremy Keala Ceramics)
Date: Fri, 23 Aug 2024 16:20:48 +0200
Subject: [Clayart] Clayart Digest, Vol 105, Issue 13
In-Reply-To: <mailman.51.1724414405.16971.clayart@lists.clayartforum.com>
References: <mailman.51.1724414405.16971.clayart@lists.clayartforum.com>
Message-ID: <CA+j6awH4TRQVvBf21osD6GZBDVVeo8Hy-0qmzuEcjSooF-p+UQ@mail.gmail.com>

Hello,

Thanks for the feedback. I've been thinking about your answers and how to
re-formulate my question so it's more precise :)

To give a bit more context to my question:
I started out looking at examples of Kuan glaze recipes, and as David said,
most are some combination of Feldspar, silica and calcium with bentonite as
a suspension agent. But then, reading through Nigel Wood's book I happened
upon a table of "Ge" glaze recipes, which appear similar to Kuan glazes in
their results. The two recipes are:

recipe 1
Potash feldspar : 63.5
China clay : 6.5
quartz : 22
whiting : 6.5
iron oxide : 0.8

Recipe 2
Potash feldspar : 28.3
China clay : 26
Quartz : 27
whiting : 14.5
dolomite : 2.5
iron oxide : 0.75

Seeing the kaolin present in these two recipes, I thought it might be
possible to not use bentonite. But as I'm not very good at using glaze
calculators for the moment, I was wondering about any suggestions of how to
go about replacing bentonite.

As an example, I tried using ball clay to modify this recipe from John
Britt's book :

original recipe
custer feldspar : 79
whiting : 9.5
silica : 9.5
bone ash : 2
bentonite : 2

modified with ball clay
custer feldspar: 63.8
ball clay : 10
silica : 13.1
whiting : 11.1
bone ash : 2

It shows up pretty similar on a glazy calculator, but I'm not very
knowledgeable about these calculations, so I was wondering if I was missing
some important detail in trying to replace bentonite with ball clay? Also,
given that original kuan glazes didn't use bentonite, I'm wondering how
this glaze settling problem was managed "back then"?

So I get that it's not generally easy to replace bentonite in a recipe, but
at the same time, I don't really understand why I can't replace it with
ball clay, like in this example that I tried. Hope my question is a bit
clearer. I just didn't want to write such a long email the first time
around!

Thanks for your suggestions, they have been very precious throughout all my
glaze testing.
Jeremy



On Fri, Aug 23, 2024 at 2:02?PM <clayart-request at lists.clayartforum.com>
wrote:

> Send Clayart mailing list submissions to
>         clayart at lists.clayartforum.com
>
> To subscribe or unsubscribe via the World Wide Web, visit
>         https://lists.clayartforum.com/mailman/listinfo/clayart
> or, via email, send a message with subject or body 'help' to
>         clayart-request at lists.clayartforum.com
>
> You can reach the person managing the list at
>         clayart-owner at lists.clayartforum.com
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of Clayart digest..."
>
>
> Today's Topics:
>
>    1. Re: Replacing bentonite (ronroy at ca.inter.net)
>    2. Re: Replacing bentonite (David Woof)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Thu, 22 Aug 2024 14:50:12 -0400
> From: ronroy at ca.inter.net
> To: Clayart international pottery discussion forum
>         <clayart at lists.clayartforum.com>
> Cc: Jeremy Keala Ceramics <jeremy.keala.ceramics at gmail.com>
> Subject: Re: [Clayart] Replacing bentonite
> Message-ID: <20240822145012.20785awwlqsqv2hw at webmail.ca.inter.net>
> Content-Type: text/plain; charset=ISO-8859-1; DelSp="Yes";
>         format="flowed"
>
> Hi Jeremy,
>
> My general rule about bentonite is:
>
> If a glaze has less than 10% kaolin bentonite may be needed to keep
> that glaze in suspension long enough while glazing pots. That?s
> because kaolins are not very good suspenders especially if there is
> any deflocculation going on.
>
> First I would swap out the kaolin and replace with ball clay using
> calculation of course. If that would not work then add 2% bentonite.
>
> There are advantages to both ball clay and bentonite. They both add a
> toughness to dried glaze (anti powdering) and glazes dry slower after
> application.
>
> There are many published glazes that do have some bentonite but may
> not need it. Yours may be one of those. If you send me the recipe I
> can give you my opinion.
>
> In some cases a glaze may be hard panning because of the local water
> or perhaps a material that is leaking sodium into a glaze over time -
> like neph sy.
>
> In the first case using a pure form of water will correct the problem.
> In the second case adding some flocculant like Epsom salts will work -
> use very little Epsom - anyone who wants my technique for finding out
> how much to use just ask.
>
> Anyway - happy to give you an opinion.
>
> RR
>
>
>
> Quoting Jeremy Keala Ceramics via Clayart <clayart at lists.clayartforum.com
> >:
>
> > Hello,
> >
> > I?m starting to work on creating a Kuan crackle glaze. My starting
> recipes
> > have bentonite in them and I don?t currently don?t have bentonite in my
> > workshop and would like to keep it that way otherwise I just keep adding
> > new materials all the time to my list of raw materials.
> > Would you have any suggestions how to go about replacing bentonite in a
> > glaze ?
> > Thanks and all the best,
> > Jeremy
> >
> >
> > --
> > *Jeremy Keala Ceramics*
> > www.jeremykeala.com
> > Instagram : @jeremy_keala_ceramics
> > <https://www.instagram.com/jeremy_keala_ceramics/>
> > +33 (0)6 59 96 92 54
> > -------------- next part --------------
> > An HTML attachment was scrubbed...
> > URL:
> > <
> https://lists.clayartforum.com/pipermail/clayart/attachments/20240816/8aef6a27/attachment.htm
> >
> >
>
>
>
> Ron Roy
> ronroy at ca.inter.net
> Web page ronroy.net
>
>
>
>
> ------------------------------
>
> Message: 2
> Date: Fri, 23 Aug 2024 00:58:21 +0000
> From: David Woof <woofpots at hotmail.com>
> To: Clayart international pottery discussion forum
>         <clayart at lists.clayartforum.com>
> Subject: Re: [Clayart] Replacing bentonite
> Message-ID:
>         <
> DM6PR15MB342084C2F5661080CEBCE4F6C68F2 at DM6PR15MB3420.namprd15.prod.outlook.com
> >
>
> Content-Type: text/plain; charset="utf-8"
>
> Hi Mary,
> Several of us now have responded to Jeremy's request for information re
> replacing Bentonite.
> I would consider it right and proper to hear back from him as to how his
> concerns are being resolved.
>
> Of course I'm not losing sleep, but the question has flitted through my
> musings that a growing number of folks may be not familiar with the
> long-time spirit of the traditional Clayart forum where unpaid experienced
> potters and studio artists give well considered information to those asking
> because of our dedication to the Craft.
>
> It is appreciated when the inquiring person responds to the conversation
> with a thank you, a request for further clarification, or of a sharing of
> their experience, which then is a return benefit for all.
>
> This goes to the spirit of Clayart that we are all here as students as
> well as teachers.
>
> In this way the learning experience of the Craft accumulates and never
> ceases as many continue to support the appreciation of Clayart value that
> keeps this valuable resource alive.
>
> Misneach,
>
> David
> Woof...............................................................................................................................................................
>
> ***************************************************************************************************
> ________________________________
> From: Clayart <clayart-bounces at lists.clayartforum.com> on behalf of Mary
> Winter via Clayart <clayart at lists.clayartforum.com>
> Sent: Tuesday, August 20, 2024 7:30 PM
> To: Clayart international pottery discussion forum <
> clayart at lists.clayartforum.com>
> Cc: Mary Winter <mary8252 at gmail.com>
> Subject: Re: [Clayart] Replacing bentonite
>
> Jeremy you can get 5 pounds of bentonite from US Pigment for $10. You might
> consider this.
>
> Mary
>
> On Tue, Aug 20, 2024 at 8:26?PM David Woof via Clayart <
> clayart at lists.clayartforum.com> wrote:
>
> > Hi Jeremy,
> > You asked for a replacement for Bentonite.  Perhaps we assumed you knew
> > the mineral qualities of the materials you have available to know you
> could
> > not just whip up a batch of what Bentonite could be replaced with.  So
> our
> > answers asked you to discern that there is no simple one material
> > substitute.
> > Macaloid and Bentonites are unique materials that cannot be substituted
> > singly or in combinations of raw materials you would likely have.  This
> > also requires understanding the intrinsic characters of each mineral and
> > the combination effects involved.
> >
> > We could have no doubt wasted your time telling you to take a high
> > plasticity synthesized Ball clay, reduce the original recipe amounts of
> > feldspar and silica and adjust the recipe ratios to accommodate these
> > additions back to the original Empirical.
> >
> > Then add enough CMC gum as a physical "mechanical" suspender, adequate
> > Hopefulness, and Sodium Silicate to deflocculate the glaze slop.    Then
> if
> > you've worked the Math correctly to arrive at a workable materials
> ratio...
> > you would still have to learn how to apply a deflocculated glaze slop
> > because the slop rheology will be way off of what most potters who use
> > flocculated glaze slops are familiar with.
> > And no doubt you would lose the Kuan Crackle glaze effect because you
> have
> > created a new Glaze. which might be an attractive glaze but not Kuan
> you'd
> > hoped for.
> > So If I gave you the adjusted amounts for this substitution most likely
> > the results wouldn't please.
> >
> > ********So back to Bentonite or Macaloid.
> >
> > Misneach,
> >
> > David
> >
> Woof.....................................................................................................................................................................
> >
> >
> ****************************************************************************************************.
> > ________________________________
> > From: Clayart <clayart-bounces at lists.clayartforum.com> on behalf of
> > Jeremy Keala Ceramics via Clayart <clayart at lists.clayartforum.com>
> > Sent: Friday, August 16, 2024 10:17 AM
> > To: clayart at lists.clayartforum.com <clayart at lists.clayartforum.com>
> > Cc: Jeremy Keala Ceramics <jeremy.keala.ceramics at gmail.com>
> > Subject: [Clayart] Replacing bentonite
> >
> > Hello,
> >
> > I?m starting to work on creating a Kuan crackle glaze. My starting
> recipes
> > have bentonite in them and I don?t currently don?t have bentonite in my
> > workshop and would like to keep it that way otherwise I just keep adding
> > new materials all the time to my list of raw materials.
> > Would you have any suggestions how to go about replacing bentonite in a
> > glaze ?
> > Thanks and all the best,
> > Jeremy
> >
> >
> > --
> > *Jeremy Keala Ceramics*
> > www.jeremykeala.com<http://www.jeremykeala.com>
> > Instagram : @jeremy_keala_ceramics
> > <https://www.instagram.com/jeremy_keala_ceramics/>
> > +33 (0)6 59 96 92 54
> > -------------- next part --------------
> > An HTML attachment was scrubbed...
> > URL: <
> >
> https://lists.clayartforum.com/pipermail/clayart/attachments/20240816/8aef6a27/attachment.htm
> > >
> > -------------- next part --------------
> > An HTML attachment was scrubbed...
> > URL: <
> >
> https://lists.clayartforum.com/pipermail/clayart/attachments/20240821/89319316/attachment.htm
> > >
> >
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL: <
> https://lists.clayartforum.com/pipermail/clayart/attachments/20240820/eb768d70/attachment.htm
> >
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> URL: <
> https://lists.clayartforum.com/pipermail/clayart/attachments/20240823/9a25ae48/attachment.htm
> >
>
> End of Clayart Digest, Vol 105, Issue 13
> ****************************************
>


-- 
*Jeremy Keala Ceramics*
www.jeremykeala.com
Instagram : @jeremy_keala_ceramics
<https://www.instagram.com/jeremy_keala_ceramics/>
+33 (0)6 59 96 92 54
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From dfinkelnburg at gmail.com  Fri Aug 23 17:15:56 2024
From: dfinkelnburg at gmail.com (David Finkelnburg)
Date: Fri, 23 Aug 2024 11:15:56 -0600
Subject: [Clayart] Clayart Digest, Vol 105, Issue 13
In-Reply-To: <CA+j6awH4TRQVvBf21osD6GZBDVVeo8Hy-0qmzuEcjSooF-p+UQ@mail.gmail.com>
References: <mailman.51.1724414405.16971.clayart@lists.clayartforum.com>
 <CA+j6awH4TRQVvBf21osD6GZBDVVeo8Hy-0qmzuEcjSooF-p+UQ@mail.gmail.com>
Message-ID: <CAFWBYeck=edW8HC+yEfq5dgePFYyikDaqA3dv9PHihb105bG9w@mail.gmail.com>

Jeremy,
      Historically, glazes were suspended with kaolin (China clay) or ball
clay.
      Bentonite works as a glaze suspender because of its relatively large
amount of surface area compared to kaolin.
      As you understand, roughly 10% kaolin or ball clay will suspend most
glazes, as will 2% bentonite, though 2% may be more than you need.
      Since your goal, as I recall, is a crackle glaze, you need to examine
the Coefficient of Thermal Expansion (CTE) as calculated by your software.
For glazes that craze, the greater the CTE the more crazing (crackle) you
will have.
            Regards,
                 Dave Finkelnburg

On Fri, Aug 23, 2024 at 8:25?AM Jeremy Keala Ceramics via Clayart <
clayart at lists.clayartforum.com> wrote:

> Hello,
>
> Thanks for the feedback. I've been thinking about your answers and how to
> re-formulate my question so it's more precise :)
>
> To give a bit more context to my question:
> I started out looking at examples of Kuan glaze recipes, and as David said,
> most are some combination of Feldspar, silica and calcium with bentonite as
> a suspension agent. But then, reading through Nigel Wood's book I happened
> upon a table of "Ge" glaze recipes, which appear similar to Kuan glazes in
> their results. The two recipes are:
>
> recipe 1
> Potash feldspar : 63.5
> China clay : 6.5
> quartz : 22
> whiting : 6.5
> iron oxide : 0.8
>
> Recipe 2
> Potash feldspar : 28.3
> China clay : 26
> Quartz : 27
> whiting : 14.5
> dolomite : 2.5
> iron oxide : 0.75
>
> Seeing the kaolin present in these two recipes, I thought it might be
> possible to not use bentonite. But as I'm not very good at using glaze
> calculators for the moment, I was wondering about any suggestions of how to
> go about replacing bentonite.
>
> As an example, I tried using ball clay to modify this recipe from John
> Britt's book :
>
> original recipe
> custer feldspar : 79
> whiting : 9.5
> silica : 9.5
> bone ash : 2
> bentonite : 2
>
> modified with ball clay
> custer feldspar: 63.8
> ball clay : 10
> silica : 13.1
> whiting : 11.1
> bone ash : 2
>
> It shows up pretty similar on a glazy calculator, but I'm not very
> knowledgeable about these calculations, so I was wondering if I was missing
> some important detail in trying to replace bentonite with ball clay? Also,
> given that original kuan glazes didn't use bentonite, I'm wondering how
> this glaze settling problem was managed "back then"?
>
> So I get that it's not generally easy to replace bentonite in a recipe, but
> at the same time, I don't really understand why I can't replace it with
> ball clay, like in this example that I tried. Hope my question is a bit
> clearer. I just didn't want to write such a long email the first time
> around!
>
> Thanks for your suggestions, they have been very precious throughout all my
> glaze testing.
> Jeremy
>
>
>
>
>
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From ronroy at ca.inter.net  Sat Aug 24 16:27:01 2024
From: ronroy at ca.inter.net (ronroy at ca.inter.net)
Date: Sat, 24 Aug 2024 12:27:01 -0400
Subject: [Clayart] Clayart Digest, Vol 105, Issue 13
In-Reply-To: <CA+j6awH4TRQVvBf21osD6GZBDVVeo8Hy-0qmzuEcjSooF-p+UQ@mail.gmail.com>
References: <mailman.51.1724414405.16971.clayart@lists.clayartforum.com>
 <CA+j6awH4TRQVvBf21osD6GZBDVVeo8Hy-0qmzuEcjSooF-p+UQ@mail.gmail.com>
Message-ID: <20240824122701.20223e8y3i65ii8l@webmail.ca.inter.net>

Hi Jeremy,

I compared ball clay (bell Dark) with bentonite using the analysis  
feature of Insight and the amount of silica is about the same but the  
alumina is lower - so choosing a ball clay with the most amount of  
alumina is probably the better way.

That would be Jackson ball clay according to the analysis I have in my  
glaze course book. I don't know if it is still available.

I can check your calculation if you tell me what kind of ball clay you used.

I can also convert the first recipe using ball clay instead of kaolin  
but what spar do I use?

I think at this point you may be seeing the wisdom in purchasing some  
bentonite - it really is a useful material.

If you want me to send you my glaze course book - send a request to my  
email. It's free to anyone who wants it - it has all the analysis I  
have collected over the years and much more.

RR

Quoting Jeremy Keala Ceramics via Clayart <clayart at lists.clayartforum.com>:

> Hello,
>
> Thanks for the feedback. I've been thinking about your answers and how to
> re-formulate my question so it's more precise :)
>
> To give a bit more context to my question:
> I started out looking at examples of Kuan glaze recipes, and as David said,
> most are some combination of Feldspar, silica and calcium with bentonite as
> a suspension agent. But then, reading through Nigel Wood's book I happened
> upon a table of "Ge" glaze recipes, which appear similar to Kuan glazes in
> their results. The two recipes are:
>
> recipe 1
> Potash feldspar : 63.5
> China clay : 6.5
> quartz : 22
> whiting : 6.5
> iron oxide : 0.8
>
> Recipe 2
> Potash feldspar : 28.3
> China clay : 26
> Quartz : 27
> whiting : 14.5
> dolomite : 2.5
> iron oxide : 0.75
>
> Seeing the kaolin present in these two recipes, I thought it might be
> possible to not use bentonite. But as I'm not very good at using glaze
> calculators for the moment, I was wondering about any suggestions of how to
> go about replacing bentonite.
>
> As an example, I tried using ball clay to modify this recipe from John
> Britt's book :
>
> original recipe
> custer feldspar : 79
> whiting : 9.5
> silica : 9.5
> bone ash : 2
> bentonite : 2
>
> modified with ball clay
> custer feldspar: 63.8
> ball clay : 10
> silica : 13.1
> whiting : 11.1
> bone ash : 2
>
> It shows up pretty similar on a glazy calculator, but I'm not very
> knowledgeable about these calculations, so I was wondering if I was missing
> some important detail in trying to replace bentonite with ball clay? Also,
> given that original kuan glazes didn't use bentonite, I'm wondering how
> this glaze settling problem was managed "back then"?
>
> So I get that it's not generally easy to replace bentonite in a recipe, but
> at the same time, I don't really understand why I can't replace it with
> ball clay, like in this example that I tried. Hope my question is a bit
> clearer. I just didn't want to write such a long email the first time
> around!
>
> Thanks for your suggestions, they have been very precious throughout all my
> glaze testing.
> Jeremy
>
>
>
> On Fri, Aug 23, 2024 at 2:02?PM <clayart-request at lists.clayartforum.com>
> wrote:
>
>> Send Clayart mailing list submissions to
>>         clayart at lists.clayartforum.com
>>
>> To subscribe or unsubscribe via the World Wide Web, visit
>>         https://lists.clayartforum.com/mailman/listinfo/clayart
>> or, via email, send a message with subject or body 'help' to
>>         clayart-request at lists.clayartforum.com
>>
>> You can reach the person managing the list at
>>         clayart-owner at lists.clayartforum.com
>>
>> When replying, please edit your Subject line so it is more specific
>> than "Re: Contents of Clayart digest..."
>>
>>
>> Today's Topics:
>>
>>    1. Re: Replacing bentonite (ronroy at ca.inter.net)
>>    2. Re: Replacing bentonite (David Woof)
>>
>>
>> ----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Thu, 22 Aug 2024 14:50:12 -0400
>> From: ronroy at ca.inter.net
>> To: Clayart international pottery discussion forum
>>         <clayart at lists.clayartforum.com>
>> Cc: Jeremy Keala Ceramics <jeremy.keala.ceramics at gmail.com>
>> Subject: Re: [Clayart] Replacing bentonite
>> Message-ID: <20240822145012.20785awwlqsqv2hw at webmail.ca.inter.net>
>> Content-Type: text/plain; charset=ISO-8859-1; DelSp="Yes";
>>         format="flowed"
>>
>> Hi Jeremy,
>>
>> My general rule about bentonite is:
>>
>> If a glaze has less than 10% kaolin bentonite may be needed to keep
>> that glaze in suspension long enough while glazing pots. That?s
>> because kaolins are not very good suspenders especially if there is
>> any deflocculation going on.
>>
>> First I would swap out the kaolin and replace with ball clay using
>> calculation of course. If that would not work then add 2% bentonite.
>>
>> There are advantages to both ball clay and bentonite. They both add a
>> toughness to dried glaze (anti powdering) and glazes dry slower after
>> application.
>>
>> There are many published glazes that do have some bentonite but may
>> not need it. Yours may be one of those. If you send me the recipe I
>> can give you my opinion.
>>
>> In some cases a glaze may be hard panning because of the local water
>> or perhaps a material that is leaking sodium into a glaze over time -
>> like neph sy.
>>
>> In the first case using a pure form of water will correct the problem.
>> In the second case adding some flocculant like Epsom salts will work -
>> use very little Epsom - anyone who wants my technique for finding out
>> how much to use just ask.
>>
>> Anyway - happy to give you an opinion.
>>
>> RR
>>
>>
>>
>> Quoting Jeremy Keala Ceramics via Clayart <clayart at lists.clayartforum.com
>> >:
>>
>> > Hello,
>> >
>> > I?m starting to work on creating a Kuan crackle glaze. My starting
>> recipes
>> > have bentonite in them and I don?t currently don?t have bentonite in my
>> > workshop and would like to keep it that way otherwise I just keep adding
>> > new materials all the time to my list of raw materials.
>> > Would you have any suggestions how to go about replacing bentonite in a
>> > glaze ?
>> > Thanks and all the best,
>> > Jeremy
>> >
>> >
>> > --
>> > *Jeremy Keala Ceramics*
>> > www.jeremykeala.com
>> > Instagram : @jeremy_keala_ceramics
>> > <https://www.instagram.com/jeremy_keala_ceramics/>
>> > +33 (0)6 59 96 92 54
>> > -------------- next part --------------
>> > An HTML attachment was scrubbed...
>> > URL:
>> > <
>> https://lists.clayartforum.com/pipermail/clayart/attachments/20240816/8aef6a27/attachment.htm
>> >
>> >
>>
>>
>>
>> Ron Roy
>> ronroy at ca.inter.net
>> Web page ronroy.net
>>
>>
>>
>>
>> ------------------------------
>>
>> Message: 2
>> Date: Fri, 23 Aug 2024 00:58:21 +0000
>> From: David Woof <woofpots at hotmail.com>
>> To: Clayart international pottery discussion forum
>>         <clayart at lists.clayartforum.com>
>> Subject: Re: [Clayart] Replacing bentonite
>> Message-ID:
>>         <
>> DM6PR15MB342084C2F5661080CEBCE4F6C68F2 at DM6PR15MB3420.namprd15.prod.outlook.com
>> >
>>
>> Content-Type: text/plain; charset="utf-8"
>>
>> Hi Mary,
>> Several of us now have responded to Jeremy's request for information re
>> replacing Bentonite.
>> I would consider it right and proper to hear back from him as to how his
>> concerns are being resolved.
>>
>> Of course I'm not losing sleep, but the question has flitted through my
>> musings that a growing number of folks may be not familiar with the
>> long-time spirit of the traditional Clayart forum where unpaid experienced
>> potters and studio artists give well considered information to those asking
>> because of our dedication to the Craft.
>>
>> It is appreciated when the inquiring person responds to the conversation
>> with a thank you, a request for further clarification, or of a sharing of
>> their experience, which then is a return benefit for all.
>>
>> This goes to the spirit of Clayart that we are all here as students as
>> well as teachers.
>>
>> In this way the learning experience of the Craft accumulates and never
>> ceases as many continue to support the appreciation of Clayart value that
>> keeps this valuable resource alive.
>>
>> Misneach,
>>
>> David
>> Woof...............................................................................................................................................................
>>
>> ***************************************************************************************************
>> ________________________________
>> From: Clayart <clayart-bounces at lists.clayartforum.com> on behalf of Mary
>> Winter via Clayart <clayart at lists.clayartforum.com>
>> Sent: Tuesday, August 20, 2024 7:30 PM
>> To: Clayart international pottery discussion forum <
>> clayart at lists.clayartforum.com>
>> Cc: Mary Winter <mary8252 at gmail.com>
>> Subject: Re: [Clayart] Replacing bentonite
>>
>> Jeremy you can get 5 pounds of bentonite from US Pigment for $10. You might
>> consider this.
>>
>> Mary
>>
>> On Tue, Aug 20, 2024 at 8:26?PM David Woof via Clayart <
>> clayart at lists.clayartforum.com> wrote:
>>
>> > Hi Jeremy,
>> > You asked for a replacement for Bentonite.  Perhaps we assumed you knew
>> > the mineral qualities of the materials you have available to know you
>> could
>> > not just whip up a batch of what Bentonite could be replaced with.  So
>> our
>> > answers asked you to discern that there is no simple one material
>> > substitute.
>> > Macaloid and Bentonites are unique materials that cannot be substituted
>> > singly or in combinations of raw materials you would likely have.  This
>> > also requires understanding the intrinsic characters of each mineral and
>> > the combination effects involved.
>> >
>> > We could have no doubt wasted your time telling you to take a high
>> > plasticity synthesized Ball clay, reduce the original recipe amounts of
>> > feldspar and silica and adjust the recipe ratios to accommodate these
>> > additions back to the original Empirical.
>> >
>> > Then add enough CMC gum as a physical "mechanical" suspender, adequate
>> > Hopefulness, and Sodium Silicate to deflocculate the glaze slop.    Then
>> if
>> > you've worked the Math correctly to arrive at a workable materials
>> ratio...
>> > you would still have to learn how to apply a deflocculated glaze slop
>> > because the slop rheology will be way off of what most potters who use
>> > flocculated glaze slops are familiar with.
>> > And no doubt you would lose the Kuan Crackle glaze effect because you
>> have
>> > created a new Glaze. which might be an attractive glaze but not Kuan
>> you'd
>> > hoped for.
>> > So If I gave you the adjusted amounts for this substitution most likely
>> > the results wouldn't please.
>> >
>> > ********So back to Bentonite or Macaloid.
>> >
>> > Misneach,
>> >
>> > David
>> >
>> Woof.....................................................................................................................................................................
>> >
>> >
>> ****************************************************************************************************.
>> > ________________________________
>> > From: Clayart <clayart-bounces at lists.clayartforum.com> on behalf of
>> > Jeremy Keala Ceramics via Clayart <clayart at lists.clayartforum.com>
>> > Sent: Friday, August 16, 2024 10:17 AM
>> > To: clayart at lists.clayartforum.com <clayart at lists.clayartforum.com>
>> > Cc: Jeremy Keala Ceramics <jeremy.keala.ceramics at gmail.com>
>> > Subject: [Clayart] Replacing bentonite
>> >
>> > Hello,
>> >
>> > I?m starting to work on creating a Kuan crackle glaze. My starting
>> recipes
>> > have bentonite in them and I don?t currently don?t have bentonite in my
>> > workshop and would like to keep it that way otherwise I just keep adding
>> > new materials all the time to my list of raw materials.
>> > Would you have any suggestions how to go about replacing bentonite in a
>> > glaze ?
>> > Thanks and all the best,
>> > Jeremy
>> >
>> >
>> > --
>> > *Jeremy Keala Ceramics*
>> > www.jeremykeala.com<http://www.jeremykeala.com>
>> > Instagram : @jeremy_keala_ceramics
>> > <https://www.instagram.com/jeremy_keala_ceramics/>
>> > +33 (0)6 59 96 92 54
>> > -------------- next part --------------
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>> > >
>> > -------------- next part --------------
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>> >
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>>
>> End of Clayart Digest, Vol 105, Issue 13
>> ****************************************
>>
>
>
> --
> *Jeremy Keala Ceramics*
> www.jeremykeala.com
> Instagram : @jeremy_keala_ceramics
> <https://www.instagram.com/jeremy_keala_ceramics/>
> +33 (0)6 59 96 92 54
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>



Ron Roy
ronroy at ca.inter.net
Web page ronroy.net



From melpots at mail.com  Fri Aug 30 17:42:57 2024
From: melpots at mail.com (mel jacobson)
Date: Fri, 30 Aug 2024 19:42:57 +0200
Subject: [Clayart] phil
Message-ID: <trinity-5af1b24c-b3d1-41fa-a986-c7ca185d98bf-1725039777403@3c-app-mailcom-lxa15>

Got a call from Phil Poburka  with is contact information
pdp1 at earthlink.net
Phone:  785 645 5013

website: www.melpots.com
WWW.clayartarchives.com


From kathy.forer at gmail.com  Fri Aug 30 18:05:16 2024
From: kathy.forer at gmail.com (Kathy Forer)
Date: Fri, 30 Aug 2024 14:05:16 -0400
Subject: [Clayart] The clay tells me
Message-ID: <CECA19DD-8194-4453-9F3F-501A986081C5@gmail.com>


Does anyone here still remember who wrote ?at first I told the clay what to do, then it told me,? but more elaborate, though they was the gist of it. I just want to say thank you!

Kathy
Kathyforer.com


From porcelainbyantoinette at gmail.com  Fri Aug 30 18:36:06 2024
From: porcelainbyantoinette at gmail.com (Antoinette Badenhorst)
Date: Fri, 30 Aug 2024 13:36:06 -0500
Subject: [Clayart] Wood firing Porcelain.
Message-ID: <CAH3_PmEbzuurGnVXpY859bd7yJFXTsUijHY=oByskKszuimXAg@mail.gmail.com>

Hi Guys. I'm still lurking mostly, but today I have something new coming up
and I think maybe the group will also benefit from a discussion.

I will be teaching in South Africa and Europe again next year. It will be
mostly my regular "Understanding Porcelain" workshop, but one studio in an
East European country asked me to help them explore local materials and
come up with a porcelain body for their wood firings and otherwise. This
will be an exciting opportunity and I hope to learn a lot from them.  The
studio is in a very clay-rich area and we already have an idea of what raw
materials will be needed. Some of it will come from existing companies and
some will be wild clay. I think they have access to some of the world's
best kaolin.... and maybe some dirty kaolin too.

We are going to wood fire the objects made in the workshop and that is
where my knowledge stops and theirs takes over. I would like to see some
rich colors come out. My thinking stops at adding some iron-based
materials, maybe in the form of slips and maybe wood ashes.

I read somewhere that placement in these kilns is also enhancing color.
At this stage, I know nothing about the kilns themselves, so maybe some
general ideas as to what to be on the lookout for will be helpful. Thanks
for your ideas.


Best wishes,

Antoinette Badenhorst



*PorcelainByAntoinette   <https://www.porcelainbyantoinette.com/#/>*

*TeachinArt* <https://www.teachinart.com/antoinette-badenhorst.html>

*International Academy of Ceramics*
<https://www.aic-iac.org/en/member/antoinette-badenhorst/>

*Mississippi Arts Commission
<https://arts.ms.gov/artist/antoinette-badenhorst/>*

*MSClayworks <https://www.msclayworks.com/#/>*
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From edouardb at colba.net  Sat Aug 31 02:04:47 2024
From: edouardb at colba.net (Edouard Bastarache)
Date: Fri, 30 Aug 2024 22:04:47 -0400
Subject: [Clayart] The clay tells me
In-Reply-To: <CECA19DD-8194-4453-9F3F-501A986081C5@gmail.com>
References: <CECA19DD-8194-4453-9F3F-501A986081C5@gmail.com>
Message-ID: <000901dafb4a$2a1853c0$7e48fb40$@net>

Mel Jacobson
Edourd

-----Message d'origine-----
De : Clayart [mailto:clayart-bounces at lists.clayartforum.com] De la part de Kathy Forer via Clayart
Envoy? : 30 ao?t 2024 14:05
? : clayart at lists.clayartforum.com
Cc : Kathy Forer
Objet : [Clayart] The clay tells me


Does anyone here still remember who wrote ?at first I told the clay what to do, then it told me,? but more elaborate, though they was the gist of it. I just want to say thank you!

Kathy
Kathyforer.com



From gerrg42 at gmail.com  Sat Aug 31 13:07:10 2024
From: gerrg42 at gmail.com (gerrg42 at gmail.com)
Date: Sat, 31 Aug 2024 06:07:10 -0700
Subject: [Clayart] Cooperation
Message-ID: <AA6B335C-9F5C-4D49-9167-BDB0FA87AD41@gmail.com>

They way I learned it, it went;
 at first the clay told me what to do,
Then I told it what to do, 
And now we cooperate!  

Gregg lindsley
Sent from my iPhone

From melpots at mail.com  Sat Aug 31 17:28:46 2024
From: melpots at mail.com (mel jacobson)
Date: Sat, 31 Aug 2024 19:28:46 +0200
Subject: [Clayart] the clay teaches
Message-ID: <trinity-d77bc780-2fa8-4b22-9511-bdd596638e46-1725125326525@3c-app-mailcom-lxa07>

it is rather a myth that the "clay teaches you".  We are involved in a complex, very difficult craft. It takes quality teachers to teach all the complex parts of clay. It starts with clay chemistry, wetness, proper mixing and experience. Throwing and hand building are very complex crafts.  It takes years to learn even the basics. A great teacher makes that time diminish. My teachers in Japan made me into a "master thrower" by repeating forms over and over in the thousands. How does a pianist learn to play??? hours of cords. And of course, a master teacher.

Think of the complexity of kilns, firing temps and glaze melting. Everything has to match perfectly.  Often the teacher that knows almost nothing will try to trick the student into learning. It is like the thought that "Pep talks will make the team play well". Well organized teaching of the team as to what to do and went to do it makes a winner.  You can have a locker room full of touch stones and it never works if the team is not prepared. Great coaches are master teachers.

As we develop as craftsperson's the materials become known to us. We have to be observant to the variations. We learn what those materials can do and "not do". The old saw really works....."practice makes perfect."
mel

website: www.melpots.com
WWW.clayartarchives.com


From ramonalclayton at gmail.com  Sat Aug 31 17:44:53 2024
From: ramonalclayton at gmail.com (Ramona Clayton)
Date: Sat, 31 Aug 2024 10:44:53 -0700
Subject: [Clayart] the clay teaches
In-Reply-To: <trinity-d77bc780-2fa8-4b22-9511-bdd596638e46-1725125326525@3c-app-mailcom-lxa07>
References: <trinity-d77bc780-2fa8-4b22-9511-bdd596638e46-1725125326525@3c-app-mailcom-lxa07>
Message-ID: <CAPD=rNXQRkwpPj915TD4aXz5mX0rk3+EC35PuCPG9MLB099Zvw@mail.gmail.com>

This is so true. In addition..we potters are passionate about the process,
actually doing it, being in and with the myriad of processes..each one of
us developing their particular connection in the process..we, (I) love the
process every minute part..and therefore am so grateful I get to do this as
much and as long as I choose..and "practice".
You ALL on this thread are master teachers to me..and I relish the
connections, making All of us a "part" of the "practice" thank you!

On Sat, Aug 31, 2024, 10:31 AM mel jacobson via Clayart <
clayart at lists.clayartforum.com> wrote:

> it is rather a myth that the "clay teaches you".  We are involved in a
> complex, very difficult craft. It takes quality teachers to teach all the
> complex parts of clay. It starts with clay chemistry, wetness, proper
> mixing and experience. Throwing and hand building are very complex crafts.
> It takes years to learn even the basics. A great teacher makes that time
> diminish. My teachers in Japan made me into a "master thrower" by repeating
> forms over and over in the thousands. How does a pianist learn to play???
> hours of cords. And of course, a master teacher.
>
> Think of the complexity of kilns, firing temps and glaze melting.
> Everything has to match perfectly.  Often the teacher that knows almost
> nothing will try to trick the student into learning. It is like the thought
> that "Pep talks will make the team play well". Well organized teaching of
> the team as to what to do and went to do it makes a winner.  You can have a
> locker room full of touch stones and it never works if the team is not
> prepared. Great coaches are master teachers.
>
> As we develop as craftsperson's the materials become known to us. We have
> to be observant to the variations. We learn what those materials can do and
> "not do". The old saw really works....."practice makes perfect."
> mel
>
> website: www.melpots.com
> WWW.clayartarchives.com
>
>
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From kanikas at starpower.net  Sat Aug 31 19:22:31 2024
From: kanikas at starpower.net (Kanika Sircar)
Date: Sat, 31 Aug 2024 15:22:31 -0400
Subject: [Clayart] the clay teaches
In-Reply-To: <trinity-d77bc780-2fa8-4b22-9511-bdd596638e46-1725125326525@3c-app-mailcom-lxa07>
References: <trinity-d77bc780-2fa8-4b22-9511-bdd596638e46-1725125326525@3c-app-mailcom-lxa07>
Message-ID: <63E1B61F0561481D821D5026E1FF7F7E@DESKTOPK9RUHCT>

I am having a show September 1-28, 2024 at Waverly Street Gallery, Bethesda 
MD.
It's called "Smoke: New Ceramics".
Please visit.

The clay never ceases to teach.

Kanika Sircar

-----Original Message----- 
From: mel jacobson via Clayart
Sent: Saturday, August 31, 2024 1:28 PM
To: clay clay
Cc: mel jacobson
Subject: [Clayart] the clay teaches

it is rather a myth that the "clay teaches you".  We are involved in a 
complex, very difficult craft. It takes quality teachers to teach all the 
complex parts of clay. It starts with clay chemistry, wetness, proper mixing 
and experience. Throwing and hand building are very complex crafts.  It 
takes years to learn even the basics. A great teacher makes that time 
diminish. My teachers in Japan made me into a "master thrower" by repeating 
forms over and over in the thousands. How does a pianist learn to play??? 
hours of cords. And of course, a master teacher.

Think of the complexity of kilns, firing temps and glaze melting. Everything 
has to match perfectly.  Often the teacher that knows almost nothing will 
try to trick the student into learning. It is like the thought that "Pep 
talks will make the team play well". Well organized teaching of the team as 
to what to do and went to do it makes a winner.  You can have a locker room 
full of touch stones and it never works if the team is not prepared. Great 
coaches are master teachers.

As we develop as craftsperson's the materials become known to us. We have to 
be observant to the variations. We learn what those materials can do and 
"not do". The old saw really works....."practice makes perfect."
mel

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