[Clayart] SANDY BOTTOMS

Mon May 2 16:50:18 UTC 2022

Vince - obviously I don't think I'm over reacting, or I wouldn't have said
anything. Each to our own. Personally I believe that grinding and sanding,
however lightly, is far worse for flinging silica into the air than
measuring out silica for glazes, and we're pretty obsessive about that.

Of course, since I really haven't ever heard of a studio potter who doesn't
smoke getting silicosis (especially in the last 20 or 30 years when we've
become significantly more aware) there is no decent evidence that any of it
really matters.

As to the flat discs, you're absolutely right. But you obviously haven't
looked around at what is available. There are actually a number of products
around that do conform to pot bottoms. There are wet grinders that have
little rubber fingers coated in diamond. There are discs made of plastic
fibers that compress and conform. If you want a DIY solution I have used a
piece of carpet with silicon carbide powder sprinkled on it. conforms very
well to pot bottoms.
As for slowness, you obviously didn't read my entire post very thoroughly
(since you were probably annoyed as soon as I disagreed with you) as the
wet angle grinder solution I mentioned is just as fast as a flap grinder,
and the pads available also conform nicely to pot bottoms. As I mentioned,
the granite countertop installers have pretty much done all of this for us.
(And there's a good reason they do everything wet).

Anyway, you do you, and I'll do me and I'm merely offering an alternative
to other readers who might also be concerned about using grinders.

On Mon, 2 May 2022 at 09:21, <vpitelka at dtccom.net> wrote:

> Hi Robert -
> If we were talking about really grinding the bottoms, dust would be an
> issue, but a light sanding with the abrasive flap wheel is enough to remove
> the grit and thus smooth the bottoms, and no noticeable dust is produced.
> I do wear a dust mask while doing this, but your warning here is an
> overreaction.  The rigid diamond disks you write about that are placed on
> the wheelhead only sand a flat surface and very few pot bottoms are
> perfectly flat.  The abrasive flap wheel conforms to the irregular surface
> and gives a lovely smooth surface.  My customers love the smooth bottoms on
> my pots.
>
> Diamond sanding pads also do not effectively conform to an irregular foot
> or bottom, and they are SLOW.
> - Vince
>
> Vince Pitelka
> Potter, Writer, Teacher
> Chapel Hill, NC
> vpitelka at dtccom.net
> www.vincepitelka.com
> https://chathamartistsguild.org/
>
> -----Original Message-----
> From: Clayart <clayart-bounces at lists.clayartworld.com> On Behalf Of
> Robert Harris
> Sent: Monday, May 2, 2022 7:44 AM
> To: Clayart international pottery discussion forum <
> clayart at lists.clayartworld.com>
> Subject: Re: [Clayart] SANDY BOTTOMS
>
> Personally, I'm really against using bench grinders because of the amount
> of silica dust they put out. and the 2.5 micron stuff that really harms
> your lungs stays in the air for 24 hours before settling (so wearing a mask
> while you're doing it doesn't really cover you). Unfortunately, the dust
> that makes you cough (10+ microns) isn't the bad stuff.
> Now admittedly, very very few studio potters get silicosis (and in the
> ones that do it's almost always co-caused by smoking), but why add to the
> risk?
>
> These days there are plenty of diamond grit solutions (like Hank
> mentioned) that fit on a wheel that allow water grinding.
> I've also seen solutions where people use air powered angle grinders
> combined with water (which is essentially how they cut granite countertops)
> if you really have a need for speed. If you look at the granite countertop
> industry in general, they solved these problems years ago (most of the
> diamond pads etc are sold to them).
>
>  All in all, wet sanding is much, much safer.
>
> On Sun, May 1, 2022, 13:55 <vpitelka at dtccom.net> wrote:
>
> > I wrote about this in one of my Clay Times columns.  I am always
> > looking for efficient ways of doing things without sacrificing quality
> > and craftsmanship.  I soda fire to cone-8 and sand the bottoms or feet
> > of every piece.  I've always done that, and when I was a production
> > studio potter in Northern California that was a hell of a lot of pots.
> > I discovered abrasive flap wheels around 1975 and since them have
> > always used them to sand the bottoms.
> >
> > Search Amazon for "Norton Metalite R265 Abrasive Flap Wheel, 1" Arbor,
> > Round Hole, Aluminum Oxide, 6" Dia., 1" Face Width, Grit 120, 6200 Max
> > RPM" but be sure to also get "Norton Aluminum Reducing Bushing for 4 -
> > 6 Abrasive Flap and Convolute Wheel, Reduces Hole Size to 1/2, 1 Arbor
> > Model: 66261080523."
> > Those are the bushings you need to adapt to the 1/2" arbor on your
> > bench grinder.  You'll only have to buy the bushings once, because
> > they fit all flap wheels with a 1" center hole.
> >
> > If you happen to have a spare 1/4 to 1/2 HP electric motor around, you
> > can get a "motor shaft arbor extension" to fit the 1/2" or 5/8" motor
> shaft.
> > It
> > features a 1/2" arbor to mount the abrasive flap wheel.  That's what I
> > did when I had Railroad Stoneware.  I mounted the motor on a stand,
> > and sanded the bottoms of every pot as I unloaded the car kiln.
> >
> > If you don't have a an appropriate electric motor lying around, you
> > are best off buying a bench grinder, because they are no more
> > expensive than a new electric motor.  They are very reasonably priced,
> > and you can use them to sharpen your trimming tools and shape your
> > modeling tools.  The Skil 6"
> > bench grinder I got for my studio does not seem to be available, but
> > the
> > "G9717 6" Bench Grinder with 1/2" Arbor" from grizzly.com for $57 is a
> > good deal.  Grizzly Industrial does a good job of maintaining high
> > quality on the products they sell.  Mount the grinder on a table or
> > workbench in your studio or buy a stand for it.  I have a bench
> > grinder in my workshop and a second one in my studio that has a
> > grinding wheel on one end for grinding off glaze runs and soda
> > deposits, and a abrasive flap wheel on the other end for sanding the
> > bottoms.  It makes quick work of the sanding.
> >
> > I bought two of the "WEN 4288T Cast Iron Bench Grinder Pedestal Stand"
> > from Amazon for $56 apiece for my bench grinders, and they worked out
> great.
> > They are a bargain.
> >
> > If you buy a bench grinder for this application, remove the grinding
> > wheel from one end and save it as a spare, and then remove the guard
> > and the tool rest from that end as well in order to give maximum
> > access to the flap wheel when sanding your work.  NEVER REMOVE THE
> > GUARD ON A GRINDING WHEEL, but with a flap wheel, the guard is just in
> > the way.  The grit and bits of fabric thrown off by a flap wheel will
> > do you no harm as long as you ALWAYS WEAR PROPER EYE PROTECTION
> > whenever using any sort of grinder or sander.
> >
> > Here's a bit of common sense shop safety protocol for bench grinders.
> > This is not so important in your own studio or workshop, but a very
> > good habit to develop for the occasions when you use a bench grinder
> > somewhere else.  If someone was walking through the workshop or studio
> > with a length of angle iron or a long two-by-four and accidently
> > whacked one end against the grinding wheel on a bench grinder and
> > cracked it, the wheel would likely explode from centrifugal force upon
> > startup.  So, as standard protocol, always stand off to the side when
> > you start a bench grinder with a grinding wheel.  That way you're out
> > of the line of fire.  Staying out of the line of fire is very
> > important whenever people are using power tools or machine tools and
> > equipment.
> > - Vince
> >
> > Vince Pitelka
> > Potter, Writer, Teacher
> > Chapel Hill, NC
> > vpitelka at dtccom.net
> > www.vincepitelka.com
> > https://chathamartistsguild.org/
> >
> > -----Original Message-----
> > From: Clayart <clayart-bounces at lists.clayartworld.com> On Behalf Of
> > Mike Gordon
> > Sent: Saturday, April 30, 2022 6:22 PM
> > To: Clayart international pottery discussion forum
> > <clayart at lists.clayartworld.com>
> > Subject: [Clayart] SANDY BOTTOMS
> >
> > Does anybody else have this problem??? All the feet on my bowls, cups
> > have to be sanded smooth. Otherwise they feel like sand paper! Mike
> > Gordon Cone
> > 6
> > in a gas kiln.=
> >
> >
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