Grace Liu on tue 19 nov 96
I've read that using crackle glaze for dinnerware is unsafe. I presume because
the cracks in the surface of the glaze can cause bacteria to accumulate there.
But I have seen dinnerware with crackle glaze on the market. So should I be
concerned about any health hazards, or not? I love the elegance and simplicity
of a matt crackle glaze, & would really like to create dinnerware with this
look. Are there safety issues I should be aware of? Or are there different
types of crackle glaze which can crackle underneath a smooth glaze surface on
top?
Any enlightenment on this topic would be greatly appreciated!
Grace
ID: 100426.757@compuserve.com
Talbott on wed 20 nov 96
Grace.... I would assume that in "reality" that a crazed glaze in high
fired stoneware or porcelain, and NOT a crackle glaze as in raku, would be
safe to use--typically it is the anerobic bacteria (they require moisture
and an oxygen free environment in order to thrive) that creates health
concerns anyway and I can't imagine how a hair-line fissure on a glazed
surface could harbor such organisms--normal dishwashing should be
sufficient---I believe one of have to use a little common since to
determine the likelyhood of the actual surface's ability to create an
unsterile environment-- so it comes down to this-- is the surface truely a
crackle glaze as in raku which would not be safe or a crazed glaze which
would be safe to use---Marshall
>----------------------------Original message----------------------------
>I've read that using crackle glaze for dinnerware is unsafe. I presume because
>the cracks in the surface of the glaze can cause bacteria to accumulate there.
>But I have seen dinnerware with crackle glaze on the market. So should I be
>concerned about any health hazards, or not? I love the elegance and simplicity
>of a matt crackle glaze, & would really like to create dinnerware with this
>look. Are there safety issues I should be aware of? Or are there different
>types of crackle glaze which can crackle underneath a smooth glaze surface on
>top?
>Any enlightenment on this topic would be greatly appreciated!
>
>Grace
>ID: 100426.757@compuserve.com
Marshall Talbott
Pottery By Celia
Route 114
P.O. Box 4116
Naples, Maine 04055-4116
(207)693-6100 voice and fax
clupus@ime.net
Tony Hansen on wed 20 nov 96
Crackle glaze come at a high price: ware strength
I have a strength testing device and in my work I have found that by the time
the thermal expansion mismatch between glaze and body is great enough to
produce visible crazing the clay-glaze combination can be up to 500% (yes,
that's five hundred percent) weaker than a best-case glaze fit situation.
--
Tony Hansen, IMC - Pulishers of INSIGHT, FORESIGHT, Magic of Fire
web: http://digitalfire.com/imc.html
JJHerb@aol.com on thu 21 nov 96
Grace: If you want crackle dinnerware for yourself, go right ahead. Use lead
glaze if you want, dust lead sulfide on wet clay and underfire it. No
problem. I won t come to dinner, thank you. But you did say "create" - this
is not for just your own use, then? Offering a warrenty for survivors?
I seem to have a low tolerance today.
Joseph Herbert
JJHerb@aol.com
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