Chrissy Desses on fri 30 jul 99
I was wondering what the level of toxicity for copper carbonate would
be if there is no lead in the glaze formulation to increase leaching,
in regards to a food safe glaze? Could anyone enlighten me?
Chrissy
way too hot and sweaty in MA
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John Hesselberth on sun 1 aug 99
Chrissy Desses wrote:
>----------------------------Original message----------------------------
>I was wondering what the level of toxicity for copper carbonate would
>be if there is no lead in the glaze formulation to increase leaching,
>in regards to a food safe glaze? Could anyone enlighten me?
>
>Chrissy
>way too hot and sweaty in MA
>_____________________________________________________________
>Do You Yahoo!?
>Free instant messaging and more at http://messenger.yahoo.com
Hi Chrissy,
Currently there is no way to predict what you want to know. The only way
to know how much copper will leach from a glaze is to have it tested.
There is no standard for copper release; however there is a significant
discussion of this in the archives--search under leaching or glaze safety
or copper or similar terms. I personally aim for as far under 10 mg/l as
I can get it; others would say we ought to shoot for the level deemed
safe for water which is 1.3 mg/l.
If you want to have glazes tested there is a complete description of how
to do that on my web site. Go to
http://www.frogpondpottery.com/glazetest.html
John Hesselberth
Frog Pond Pottery
P.O. Box 88
Pocopson, PA 19366 USA
EMail: john@frogpondpottery.com web site: http://www.frogpondpottery.com
"It is time for potters to claim their proper field. Pottery in its pure
form relies neither on sculptural additions nor on pictorial decorations.
but on the counterpoint of form, design, colour, texture and the quality
of the material, all directed to a function." Michael Cardew in "Pioneer
Pottery"
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