Malone & Dean McRaine on wed 14 may 97
Aloha John. Thanks for your comments on my scrap glaze method. Health
issues are not my strong point and I'd hate for my ignorance to cause
problems for others. Fortunately I don't use lead, little barium, and
virtually no potentially hazardous (cadmium, etc) stains or prepared
glaze/underglaze/overglaze materials so I don't end up with them in my
scrap. Could be a vastly different story in a school. Would you still
consider my scrap glaze not food safe? What tests could determine this?
Also I'm wondering if there is there something about Iron Chromate and
Manganese that would render a glaze unsafe if it contained substantial
(6-8%) amounts of these compounds.
Dean McRaine
Ron Roy on thu 15 may 97
>----------------------------Original message----------------------------
>Aloha John. Thanks for your comments on my scrap glaze method. Health
>issues are not my strong point and I'd hate for my ignorance to cause
>problems for others. Fortunately I don't use lead, little barium, and
>virtually no potentially hazardous (cadmium, etc) stains or prepared
>glaze/underglaze/overglaze materials so I don't end up with them in my
>scrap. Could be a vastly different story in a school. Would you still
>consider my scrap glaze not food safe? What tests could determine this?
>Also I'm wondering if there is there something about Iron Chromate and
>Manganese that would render a glaze unsafe if it contained substantial
>(6-8%) amounts of these compounds.
>Dean McRaine
Excuse me for butting in but - whether a glaze is "safe" or not depends on
two factors. How resistant to attack the glass is and what is in the glaze
that is a potential problem. We can't know how durable a scrap glaze is
without testing it for leachability. Over loading a glaze with colourants
can ony make the situation more of a problem. Firing those glazes on the
outside of pots would be the best solution. I should also add - you should
make sure your kiln area is very well ventilated.
Ron Roy
Toronto, Canada
Evenings, call 416 439 2621
Fax, 416 438 7849
ronroy@astral.magic.ca
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