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The Graphite Kiln Shelf
Graphite seems like it would be an ideal
material for a kiln shelf. It's commonly used by bead
makers and glassblowers to shape glass. It can easily
withstand the heat of the torch, can be used as a mold for
shaping beads, and leaves a smooth, glossy finish on the glass.
It's also available in several forms, including smooth slabs that
seem ideally suited for the kiln.
Despite these desirable characteristics, graphite does not make
a good kiln shelf. If used in a kiln, it will work well
for the first firing, and sometimes for the second, but by the
time it has been fired several times the graphite starts to
disintegrate. Continue firing and you're soon left with a
pitted surface, chunks of broken graphite, and ugly black dust
all over the kiln. The reason
graphite works well for lampworking and bead making but won't
work for kiln shelves is that fusing requires the shelf to be
exposed to high heat for a long period of time. This
starts to break down the shelf and eventually makes it decompose
entirely. In glassblowing and torch working, by contrast,
the graphite is only in contact with the glass for a very short
period of time, so problems of prolonged exposure are avoided. ----------------
Copyright 2005 Brad Walker. All rights
reserved.
Most of these tips came from
posters on the Warm Glass bulletin board.
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