Jonathan Kirkendall on sun 8 sep 96
I want to know how safe lithium is in low fire glazes. There seems to be
some confusion about this. I know some potters who treat it like lead,
others who recommend only using it above cone 6, others have told me it's
okay in a shiny glaze, but not a mat glaze. My glaze material supplier tells
me its safe. Robert Piepenburg is his book THE SPIRIT OF CLAY lists it under
Toxic Materials to Avoid along with lead, barium, and uranium yet includes it
in six of his low fire glaze recipes!
I have a cone 04 lithium mat glaze that is often mistaken (by other potters)
for a high fire reduction glaze, and I like to use it, but not if it's
unsafe, or even questionable.
Does anyone know? Thanks, Jonathan in Yonkers
Ron Roy on sun 8 sep 96
Hi Jonathan,
There are two questions here.
How much Lithium is released from the glaze and how much is toxic.
How much is released has to do with the durabilty of the glaze which has to
do with the molecular structure. The chances of the glaze being durable are
better with shiny glazes but you CANNOT tell from looking at a glaze. I
don't even feel comfortable using calculation - testing would be better but
glazes change with firings and the natural variation of the materials we
use.
I do know it is easier to make better glass at higher temperatures
Ron Roy
Toronto, Canada
Evenings, call 416 439 2621
Fax, 416 438 7849
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