Disaster! Is this a kiln problem?
Posted: Wed Jun 01, 2016 4:12 pm
I hope someone has seen this before and can tell me where to look for the problem.
Two bubble-up firings. The first is fine and was slumped into a plate. Next was 4 smaller pieces on the same schedule. All have multiple cracks. The cracked one in the lower right is even the same glass. What happened?
Everything was the same except the size of the glass (7” vs 4 ½”) a different kiln shelf and I noticed the total time in the kiln was 8:02 vs 8:20 for the ones that cracked. Cracks are sharp so it happened on the way down, and some places are really stuck to the kiln shelf. Thermocouple bad? Controller bad?
Schedule:
400/hr to 1100 hold 10 min
AFAP to 1700 hold 45 min
AFAP to 925 hold 60 min
100/hr to 750 off
No problem here Disaster Spread out
Two bubble-up firings. The first is fine and was slumped into a plate. Next was 4 smaller pieces on the same schedule. All have multiple cracks. The cracked one in the lower right is even the same glass. What happened?
Everything was the same except the size of the glass (7” vs 4 ½”) a different kiln shelf and I noticed the total time in the kiln was 8:02 vs 8:20 for the ones that cracked. Cracks are sharp so it happened on the way down, and some places are really stuck to the kiln shelf. Thermocouple bad? Controller bad?
Schedule:
400/hr to 1100 hold 10 min
AFAP to 1700 hold 45 min
AFAP to 925 hold 60 min
100/hr to 750 off
No problem here Disaster Spread out