Jeff Tsai on mon 2 sep 02
"Hello to all,
Curious...what is a safe temperature to open a glaze
kiln and or a bisque kiln? At school they told us not
to touch the kiln to 125 degrees! What is a safe
temperature?
Thank you, Marie"
Marie,
First, I assume you're talking about degrees F, and so will I
If your teacher told you not to touch a kiln before it fell below 125
degrees, then, whenever you're working at school and have a kiln that hold
pieces that are not solely your own, you should only open the kiln after 125
degrees.
If you have a kiln of just your work, and the teachers aren't around, then
you can maybe play with that limit.
Really, it depends on lots of things that I'm sure other people have already
mentioned. Some clays are less resistant to thermal shock than others. Some
forms are more prone to cracking. Some forming methods are more likely to
crack, etc. etc.
Skutt Electric Kiln manuals give a nice round 140 degrees as the highest
temperature to open their kilns.
I can only give you my experiences...I've opened a kiln filled with thrown
bowls, cups, mugs, etc. made of porcelain and Bee Mix at 225 degrees and they
came out fine.
I've opened a kiln with a life-size sculpture made of rolled slabs using a
groggy red clay at 200 degrees and watched as the leg suddenly came snapping
off the hip.
-jeff
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