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crazing and the responsible potter.

updated thu 20 dec 07

 

Vince Pitelka on tue 18 dec 07


Lili Krakowski wrote:
> All over the world people have polluted water, coli infested veggies, a=
nd
> salmonella tainted chicken. So what? Are these things guidelines?
> I am sure that also all over the world lead is still used in glazes and
> some
> of that ware is brought into this country by returning travelers. I a=
lso
> know that lead glazed food related wares still is imported into the US
> market...
> None of this lets The Responsible Potter off the hook! We are educated
> folk, we can read, we can search the Internet, we are blessed with expe=
rts
> who work for ceramic suppliers--and that some poor soul in the depth of
> the
> jungle makes toxic clay soup bowls and sells them to missionaries and
> tourists, hardly means we should imitate him!
> Just as a Responsible Seamstress will make sure a lining does not shrin=
k,
> that a hem is even, that buttons and buttonholes are actually opposite
> each
> other, a Responsible Potter makes sure the glaze does not craze, the gl=
aze
> does not leach, the pot does not shiver....

Dear Lili -
Nothing is gained by getting melodramatic about this. Of course every
potter should be fully conscious of and honest about every implication of
crazed glazes on any ware that is sold to the public, but the reality is
that crazing is a structural problem and nothing more. The other problem=
s
you mention are either food safety issues or severe structural issues
(shivering). You make a good point, but I worry about others
misinterpreting it because of all the horrors and dangers you mention tha=
t
have nothing at all to do with a crazed glaze.

A responsible potter should try to prevent glazes from crazing, but most
salt-glazed pots have crazing in the glaze, and there's no way to prevent
it in salt firing. At lowfire temperatures, it is very difficult to
achieve an unleaded clear glaze that does not craze, and as you mention,
most lowfire glazes craze over time. And as I have said before, through
history there is no evidence that anyone was ever sickened by eating food
from a dish with a crazed glaze.
- Vince

--=20
Vince Pitelka
Appalachian Center for Craft
Tennessee Technological University
vpitelka@dtccom.net
http://iweb.tntech.edu/wpitelka/

Lili Krakowski on tue 18 dec 07


All over the world people have polluted water, coli infested veggies, and
salmonella tainted chicken. So what? Are these things guidelines?

I am sure that also all over the world lead is still used in glazes and some
of that ware is brought into this country by returning travelers. I also
know that lead glazed food related wares still is imported into the US
market...

None of this lets The Responsible Potter off the hook! We are educated
folk, we can read, we can search the Internet, we are blessed with experts
who work for ceramic suppliers--and that some poor soul in the depth of the
jungle makes toxic clay soup bowls and sells them to missionaries and
tourists, hardly means we should imitate him!

Just as a Responsible Seamstress will make sure a lining does not shrink,
that a hem is even, that buttons and buttonholes are actually opposite each
other, a Responsible Potter makes sure the glaze does not craze, the glaze
does not leach, the pot does not shiver....

Earthenware clay will absorb water....
Even if the glaze fits when it comes out of the kiln, the pot will expand
through
-from use, from washing--and the glaze will craze over time. Not all glazes
craze over all earthenware--
but a good many do.

So --regardless of what goes on elsewhere, the Responsible Potter evaluates
what she is producing. Do I feel comfortable if coffee gets into the glaze
fissures and the cup has a crackled look? What do I tell someone with an
impaired immune system when she asks about the crazing? Can I take pride in
making something less than as good as can be?











Lili Krakowski
Be of good courage