Daniel W Kirkland on sun 17 aug 97
I would like to know if anyone has any information regarding the use of
lithium carbonate in clay bodies.
I am interested in lithium carbonate in clay bodies, because I did a clay
experiment using lithium carbonate in porcelain. The clay formula for
this clay is:
Porcelain (cone 10)
Grolleg Kaolin 50
Nepheline Syenite 12.5
Cornwall Stone 12.5
Silica 25
Lithium Carbonate 0.5
When fired in oxidation, the clay was a glazed glossy white on the areas
which were exposed to the atmosphere of the kiln; yet the bottom of the
tile, which was against the kiln shelf, looked like a typical porcelain
-- not glossy and white.
When this clay was fired in reduction (the reduction in this case was a
light reduction from cone 06 to cone 10), the areas which were exposed to
the atmosphere literally had the characteristics of an orange peel; it
had the orange color and texture of an orange peel.
I did another test of a clay similar to the first one:
Porcelain (cone 10)
Grolleg Kaolin 35
Tennessee Ball Clay #1 15
Nepheline Syenite 12.5
Cornwall Stone 12.5
Silica 25
Lithium Carbonate 0.5
This clay was fired in reduction. And the surfaces which were exposed to
the atmosphere looked much more like a shino glazed surface. The surface
which was not exposed to the kiln atmosphere looked like the usual
porcelain surface.
Roger Porter at Glendale College later did an experiment using EPK Kaolin
instead of Grolleg Kaolin, and it is my understanding the surface of
this porcelain did nothing exceptional. Instead, it only looked like a
basic porcelain.
So I am looking for any information beyond what I have here regarding
lithium carbonate in clay bodies. I also understand that Gerstley Borate
in clay bodies has interesting effects. However, I have not experimented
with this. So I would also be interested in any information regarding
Gerstley Borate in clay bodies.
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