Skutt FireBox8x6 LT - Manual (Page 10)

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Overview
Glass Fire Mode was developed by Skutt in order to provide
glass artists with a simple way to fire their glass projects without
having to be an expert in programming. The built-in programs
were designed by glass artist Gil Reynolds to work with the
two most popular types of fusible glass, COE 90 and COE 96.
Fusible glass is glass that is specifically designed to be “compat-
ible” when fused together. Glass that is compatible will have the
same Coefficient of Expansion (COE). This means it will expand
and contract at the same rate when it is heated and cooled.
Glass that has different COE’s will create stress in the piece
when it is fired and will likely crack. So when choosing glass
for your project be careful never to mix your COE 90 and COE
96 and never use glass that was not specifically designed to be
compatible.
Glass Fire Mode has programs available for Slumping, Fusing, and Tac Fusing. All the programs are carefully designed
to prevent shocking the piece while it is heating or cooling and for proper annealing. The programs vary based on the
size and thickness of the piece you are firing. The wider and/or thicker the piece, the slower you need to fire it and the
longer you need to anneal it.
Glass gets “shocked” when one potion of the glass heats or cools faster then another portion. By slowing the firing you
limit the potential for this to happen.
Annealing has more to do with the glass transforming from a fluid state back to a rigid state when it is cooled. You want
all the molecules to go through this transition at the same time and at the same rate. This happens generally between
750°F (399 °C) and 1000°F (538 °C). The controller will slow down the cooling rate of the kiln through this period
by cycling the heating elements on and off. Once past this range the kiln will shut off and cool at a natural rate. Never
open the lid until the kiln has cooled completely.
To program the kiln you will need to give it two pieces of information; What Speed and What Process?. You may have
to make slight adjustments to the peak temperature and hold time to adjust for certain projects but for the most part you
will stick with the factory settings.
Speed
As mentioned earlier, the speed you choose will depend on the size of the project. We have made it simple for you by
providing this chart to make your selection. If you have multiple pieces in the kiln at once, use the speed that corre-
sponds with the largest piece. You rarely have problems firing too slow.
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