Quartz glass, sometimes called fused quartz
or fused silica, is a clear glass that is notable for its ability to
withstand high temperatures. It is made by melting pure
quartz. The resulting glass is extremely clear, virtually
transparent to light from both the visible and invisible (infrared
and ultraviolet) spectrums. It also has a low coefficient of
expansion (COE), making thermal shock very unlikely. And
finally, it is stronger than ordinary glass.
These properties make quartz glass an
excellent glass for use in several applications in the kiln.
One of these is in viewing windows for kilns, where quartz can
undergo rapid temperature changes and high kiln temperatures without
breaking or changing shape. The softening point for quartz
glass is 3030F/1655C, well above the normal operating range for
Another common use for quartz glass is as a
sheath for kiln elements. This requires quartz glass in tube
form. Elements are contained inside the tube and fixed to the
top and sides of a kiln as required. Not only does this kind
of installation keep elements from drooping, it also virtually
eliminates the problem of refractory dust falling from the kiln lid
and onto pieces being fired.
Copyright 2005 Brad Walker.
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