[Clayart] Crash cooling and a funny story

Fri May 11 16:11:44 EDT 2018

Mel wrote:
as happens in industry, the warm up to cone is gradual but with controlled
speed.

A  tunnel kilns went from cool to cone 2 or 3 and back in like 45 minutes

Jeff
Jeff Lawrence
jefflawr at gmail.com
jeffreylawrence.net

On Fri, May 11, 2018 at 10:00 AM, <clayart-request at lists.clayartworld.com>
wrote:

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> Today's Topics:
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>    1. Re: Crash cooling the soda kiln to keep orange peel effect
>       (Robert Harris)
>    2. Re: Soft pots and mailing... Rox (Girrell, Bruce)
>    3. crash cooling and funny story (mel jacobson)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Thu, 10 May 2018 21:55:45 -0600
> From: Robert Harris <robertgharris at gmail.com>
> To: Clayart international pottery discussion forum
>         <clayart at lists.clayartworld.com>
> Subject: Re: [Clayart] Crash cooling the soda kiln to keep orange peel
>         effect
> Message-ID:
>         <CAL12t+hgXRBNKrHJR52OM8qS5MJBH16zTm9A
> eAKoDLBUt89uVA at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> I saw a firing at Anderson Ranch on the penultimate day of a workshop. They
> quite literally opened the whole entire door of one of their big kilns at
> Cone 10. It was quite amazing (and I have the photos to prove it!). Now
> that's crash cooling! As I recall they took it down to 1100C (2000F - but
> they use C up there) over the course of about 15-20 minutes by pulling the
> door open then shutting it. The kiln was cool by the next morning, pots
> none the worse off.
>
> On Thu, May 10, 2018 at 4:57 PM, Snail Scott <claywork at flying-snail.com>
> wrote:
>
> >
> >
> >
> > > On May 10, 2018, at 8:44 AM, Helen Stone <helenestonepeony at gmail.com>
> > wrote:
> > > ...
> > > crash cooling to maintain the effect, does this specifically mean, I
> just
> > > turn off the burners, but leave some areas open for a big (how long is
> a
> > > bit), like for e.g. I could leave the burner ports open and not plug
> them
> > > up for awhile, I could open the soda ports and cone observations ports,
> > > this would be really crashing, not sure if I should do that!...
> >
> >
> > It appears to me that when crash-cooling to ?set? a glaze, you just need
> > to get it below the melt threshold.  In my experience (fairly limited,
> as I
> > don?t do it much) crash-cooling won?t really ?shock? the clay until it
> gets
> > cooler than that, as everything is still a bit soft and flexible until
> > then, and there is enough thermal mass in the average fuel kiln to keep
> > things a bit warm anyway. I wouldn?t worry about overdoing the cooling
> rate
> > until you reach the lower ranges of red heat.
> >
> > Snail Scott
> > claywork at flying-snail.com
> > www.snailscott.com
> >
> >
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> ------------------------------
>
> Message: 2
> Date: Fri, 11 May 2018 14:58:14 +0000
> From: "Girrell, Bruce" <bigirrell at microlinetc.com>
> To: Clayart international pottery discussion forum
>         <clayart at lists.clayartworld.com>
> Subject: Re: [Clayart] Soft pots and mailing... Rox
> Message-ID:
>         <BYAPR07MB43591B01A79E69BCB3CCA581B69F0 at BYAPR07MB4359.
> namprd07.prod.outlook.com>
>
> Content-Type: text/plain; charset="utf-8"
>
> When I was in college, I worked for UPS, so I got some experience in
> seeing the results of good packing and bad. What I tell people is that you
> should pack fragile items such that they can withstand a fall of 10 feet to
> a concrete floor and can tolerate someone stepping on the package.
>
> This is not because UPS workers or other shippers are careless; it is
> simply the reality of dealing with packages in large trucks. When the
> workers pull open the rear door of a truck, if there are any packages up
> high near the door, they will fall out. The workers may try to catch what
> they can, but there are usually only two unloaders per truck, meaning that
> a maximum of about four packages can be caught. The rest fall, up to 10
> feet, to the concrete loading dock. And while no one really intentionally
> steps on a package, sometimes it happensdue to loss of balance or not being
> able to see a stray package. Or the wheel well inside the truck that the
> worker is standing on may end sooner than he thinks it does and the next
> step goes on a box.  Assume that it's going to happen to your package.
>
> Double boxing, as recommended by others is a very good technique. In all
> cases, you want to restrict mobility. _Nothing_ in the box should be able
> to move when you finish packing. If I had only one thing I could say about
> proper packing it would be to make sure that nothing in the package can
> move. The foamed-in-place packaging, available at many shipping stores, is
> superb in this regard, but it costs a bit.
>
> Peanuts and bubble wrap serve two different purposes. Peanuts can crush
> and absorb shock. I have a cousin who ships optical instruments like
> surveyors' transits. He insists on peanuts because their shock absorbing
> capability minimizes vibrations that can affect the instruments' alignment.
> But peanuts move. A pot that starts its journey in the middle of a batch of
> peanuts may end up at the side of the box by the end of the trip. Smaller
> pieces can up anywhere. Bubble wrap stays in place and ensures a minimum
> distance to the sides of the box, as well as providing physical protection
> and providing separation between individual pieces inside the box.
>
> So, my recommendation would be bubble wrap around the pot, with separate
> wrap for lids or other loose parts, plus peanuts to fill any voids in a
> box. Then that box goes into a larger box with peanuts in an even layer,
> at least a couple inches thick on _all sides_, around the interior box.
> Don't forget a layer of peanuts for the bottom and top. This allows the
> exterior box to take severe abuse while passing little of it on to the
> interior box. And the interior box is like a rock, packed tight so that any
> forces move uniformly through the box.
>
> Clay objects are strong in compression. Forms created on a wheel are
> revolutes and will be fairly strong. Any object whose length is
> significantly more than its width should be reinforced, for example, by
> attaching it to a piece plywood or sandwiching it between pieces of
> material before wrapping with other protection. Place padding between the
> object and its support material. Dense foam is good for this purpose.
>
> And yes, your time and the materials count. If you're valuing your time at
> $20/hour and it takes half an hour to pack the box, then a packing charge
> of $10 plus, say, $5 more for the materials is not in any way out of line
> for a pot. Mugs and smaller items, of course, use less time and materials,
> but you still deserve to be paid for your work time, whether it is creating
> or packing.
>
> Bruce Girrell
>
> ------------------------------
>
> Message: 3
> Date: Fri, 11 May 2018 10:07:04 -0500
> From: mel jacobson <melpots at visi.com>
> To: clay <" clayart"@lists.clayartworld.com.>
> Subject: [Clayart] crash cooling and funny story
> Message-ID: <5AF5B198.5080907 at visi.com>
> Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"
>
> kurt, nils and our group looked into crash cooling years back.
> it works to a degree, but is, in our opinion, a rather silly way to
> deal with pots.  down firing is the answer to the entire story.
> (ask me for my book if you do not have it...pdf file, free of charge)
>
> as we have talked about all winter, i am speed firing and speed
> cooling my new clay and glaze.
> but, it is natural cooling...whatever the kiln will tolerate.
> and that three hour down firing is very gentle and
> fits with the schedule.  i do not open the kiln at all
> during cooling.  watch the pyrometer go down slowly.
> but, the kiln can easily cool to 500 in about four hours.
> i do not lift the lid til it is at 150F.
>
> the pots have no ill effect.  they ring true, have no dunting, shivers
> or other awful problems.  there has not been a crack in the two hundred
> or more pots i have fired with my electric kiln.
>
> as happens in industry, the warm up to cone is gradual but with controlled
> speed.  the pots are in the cone area for about ten minutes or less.
> the cooling again is gradual and controlled.  no shocks, ever.
> climb to the top, and let it cool the same way.  perfect bell curve.
>
> if you open a kiln in that thousand degree range, the pots
> will be ruined.  we had a dork at the farm open our big
> stoneware kiln at 1200 and snatch his pots and went home.
> the entire kiln of pots was ruined..like 80 pieces.
> some could be saved, but most had baby cracks.
>
> if you are working for speed, you had better chart what you are doing
> and keep to a strict schedule.
>
> my study is not about rushing to get things done.
> we all can wait. never ruin pots.
> my tests are about what the clay and glaze will tolerate.
> it is about testing limits.  that has always been the study
> of mine, kurts and nils.  how far can you push, then back off.
> find the prefect system for  timing, fuel saving and  great pots
> that sing.  i have reached that point in my new firing schedule.
>
> funny story,.  i stopped at a garage sale yesterday, had a
> five dollar bill that i keep in my glove box....was looking for new
> stuffed toys for my golden...she loves new toys. 1$  each
> got 5.
> but, as i parked ,a lady with a big black bentley  car pulled next to
> me. (like 125 thousand dollar car) ?? who knows.
> i helped her out of the car, you know on a little hill and grass. she
> was like
> 70...lovely looking, great clothes.  she was old enough to appreciate a
> gentleman.
> we walked over to the tables and she was snatching a few things.
> i said to her.
> `it is really nice to be shopping at a garage sale with a lady that
> parks her bentley  and looks for bargains.` ` said the old line.
> `how do you think i can afford a bentley...?  ```  she wanted to
> buy my gold teddy bear, offered me two bucks...but, i could not
> sell saffron's gold bear,  there are limits to making money.
> mel
>
> --
> Mel's Website:  www.melpots.com
> CLAYART PAGE:
> http://www.melpots.com/CLAYART.HTML
>
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