Quote:
Originally Posted by JavaGirlBT
I purchased a kiln thermometer (pyrometer - I had to google it to find the word) from Malcolm a couple of years ago and it showed that my kiln was running approximately 100 degrees hotter than what was displayed. I had always felt it was too hot because of slumping and over-striking that was going on. My kiln reads 850 and it's actually at 925 for annealing.
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Yes, and if Ravenesque's kiln were running cooler - say 100 degrees - then annealing at 925 would in fact be 825 which is lower than the 840 strain point of Effetre, thus the cracking.
That's why I always advice my students to lower the annealing temp 10 degrees at a time and no lower than 920 if they have trouble retaining the silver glass effects in the kiln. And if it's still not working, then get a pyrometer to make sure the kiln temp is in fact accurate especially if they have cracking issues.