Kiln Cooling

[tgotch]

I have been playing around with my new kiln and slumping bottles I had a question on kiln cool down.

Is there a temperature at which you open the door to help expedite cooling? I have some people say to "crack" the door at ~400 degrees, and ok to open at ~200.

What do you do? Is there any other alternatives to expedite cool down?

[Kevin Midgley]

Do not rush when firing bottles. Keep kiln closed until near room temp.
They are uneven thickness.

[Stephen Richard]

Ditto to what Kevin says. The uneven thickness means any quick change of temperature in the 100-200ºC range will allow the thinner parts to cool quickly enough to induce thermal shock.

[rosanna gusler]

yep. just for s&g take a pair of calipers and measure the thick part of a slumped bottle. it can be suprisingly thick. rosanna

[Morganica]

A fused bottle is also a bit more prone to stress than a solid chunk of glass would be at that thickness. With a bottle the collapsed sides come together but may not completely fuse together in spots, especially if there are bubbles. Wherever the glass separates, that joint is an increased opportunity for stress, which actually argues for increasing the time, not decreasing it.