This is part two of a two
part tip on using Armstrong Ceramaguard in the kiln. Click
here to go back to part one.
Although it warps less than fiber board, Ceramaguard should
still be well supported with kiln posts during firings. It is
strong enough to stand on end if desired. No separator is required
for temperatures below 1300 to 1350 F (roughly 700 C), but because
the texture of Ceramaguard is sometimes uneven fiber paper or kiln
wash is often used to impart a particular texture to the underside
of the glass. It has a low thermal mass and heats (and cools
Ceramaguard can also be used at fusing temperatures, but a
kiln wash or fiber paper is highly recommended. Best results are
achieved with pieces that are one square foot or less and are well
supported in the kiln. Larger pieces of the board tend to warp at
fusing temperatures, but smaller pieces may be suitable for use as a
kiln shelf, especially if well supported with kiln posts.
Ceramaguard is fragile and must be treated with care, but with
proper treatment it will last quite a while. It needs to be
pre-fired to 1250 F (it will smell like burning sugar and may give
off some smoke, so make sure your kiln is vented slightly) The paint
will flake off during firing (especially the first firing). You may
fire on either the painted or unpainted sides of Ceramaguard, and
may cut or carve the Ceramaguard either before or after pre-firing.
From a health perspective, Ceramaguard is safer than most
ceramic fiber boards, but it is not perfectly harmless. It is made
of fiberglass wool, which irritates some people, especially those
with lung conditions or sensitive skin. It should be handled with
And finally, other ceiling tiles do not perform as well as
Armstrong Ceramaguard (they melt, blacken, or fall apart --
sometimes all three), so stick to Ceramaguard for use in the kiln.
Copyright 2005 Brad Walker.
All rights reserved.
Ceramaguard can be purchased by
the case at most building supply stores (builder's supply, not
a home improvement or DIY store like Home Depot or Lowes).
Individual squares can also be purchased from the Warm Glass website