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macro-crystalline glazes/cranky joyce

updated thu 6 jun 02


william schran on wed 5 jun 02

>Joyce wrote:
"I was stopped in my tracks by the daunting piece of info that such
glazes must be fired in a "saucer" ... a saucer which will then
become attached to the pot, needing to be detached after firing, and
the bottom of each pot ground.
Questions: Is this information accurate?"

Joyce - The information is semi-accurate. A saucer for each work is
highly advisable. Crystalline glazes have very little alumina content
and will run. The movement of the glaze is necessary for good crystal
growth. One can use a "normal" glaze on the bottom half of the pot
and limit the crystalline glaze to the upper half to avoid the
saucer. Some folks (I think Brad Sondhal was doing this) have worked
with the glazes long enough to know how much the glaze will run and
can avoid using saucers, though I don't know how large the crystals
were. I also worked with multiple layered glazes that included a mat
glaze containing zinc when layered over other glazes would become
very glossy and form small crystals.
Traditionally a pedestal made of clay or brick is used and broken
loose after firing, then bottom of pot is ground smooth. I do this
and have used a method where the pedestal breaks free fairly easily
with minimum grinding involved.
There is more time and effort involved with crystalline glazes - it's
just part of the process. Each person has to decide how they want to
expend their energy to achieve a specific goal.

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