Patty Gray: On Combing with System 96®

Combing is one way of manipulating hot glass in a kiln. Complete how-to details can be found in any number of Hot-Glass resources.
System 96 products are particularly suited for hot-manipulation due to low melting temperatures and long working ranges. Here, accomplished artist Patty Gray shares her notes specific to making her spectacular large combed platters with System 96.
Glass:
18" x 18" clear glass sheet laid on ceramic fiber paper
1/4" x 18" glass strips standing on edge supported with two strips stacked flat on each end
Step
Temperature
Time
1
300º
45 minutes
2
750º
45 minutes
3
1000º
45 minutes
4
1700º
2 hours but start combing at 1650º
Once the kiln reaches1650º, I begin combing. (System 96 glass is molten enough to comb at lower temperatures than other glasses. This not only saves energy but helps prevent bubbles and color changes.)
After each combing I shut the kiln and wait for the temperature to reach 1650º and repeat the process until the desired pattern is achieved. I take the temperature back to 1650º to level out the glass (the valleys made from the combing fill in). I do not hold the temperature at 1650º at all. System 96 doesn't need it.
I flash vent the combed piece to 1100º. Dropping the temperature back to this level will prevent further fusing and devitrification. If you drop the temperature below 1100º you run the risk of warping the glass sheet or possibly cracking the glass itself.
I set the anneal for 4 hours 960º then set 2 hours 850º. At this point my firing is done and kiln remains shut until room temperature is reached.
Resist the temptation to open the kiln too soon! The only times I have experienced breakage (thermal shock) wasn't because of the glass or the annealing schedule - just impatience!
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