by Kim Bergo
(Bozeman MT USA)
Question:
My junior cone (sitter cone) bends shutting off my kiln after 7 hours at 05 cone but the senior cone doesn't bend and is at the same level as the sitter. What could I be doing wrong? Is it reaching cone 05?
Answer:
That's interesting... could be a few things.
1. Double check to make double sure they are both the same cone number (one could be 05 and the other 5, for example).
2. Even if they're on the same level, the sitter cone could be receiving more heat that is circulating around the walls of the kiln?
3. Does the pottery seem to be fully fired? If so, I wouldn't worry too much about the big cone not melting.
4. Is the big cone at a sufficient angle to fall over when heated?
5. Finally, are you using a cone pack, with 06, 05 and 04 cones? That's the best way to do it because you should definitely see that the 06 cone is melted. If so, you know that you're very close. If not, then you have more cause to worry about it being under-fired.
Hope that helps.
Steve
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