Thermal Shock? help…

[FieryVisions]

I was just broken hearted when I opened kiln this morning to a totally ruined piece.  Fused a 6×6 tile using this schedule:

300/hr   1100  .10

150/Hr   1240  .30

Full          1450  .15

Full.            980  .30

Full.             700 stop

 

Using 2 layers, 6mm coe90. I used a little cmc to hold pieces together. ONLY thing I can think is that atound 900 (on ramp up) I modded program to go a little higher on target temp…but kiln was only stopped for 30 secs at most. Could this have caused it? I thought my schedule was fairly conservative. Cant figure why this happened. Any help is appreciated

[Anonymous]

If the broken edges are sharp (and I’m guessing they are) your piece broke on the way down. Full speed for annealing (980 – 700) is too fast.

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Paul
FusedGlass.Org
Helios Kiln Glass Studio
PaulTarlow.com

 

[FieryVisions]

Thank you Paul! I had only done smaller pieces until now so it never effected them. I also thought that the long hold was sufficient. I appreciate the tip so if I slow to about 200 º /hr on the way down should that be slow enough?

[wordana]

Also, your annealing temp is too high. It is 950 for system 96, and I believe 900 for Bullseye 90 COE.

Between the incorrect temp and the quick schedule, you were never hitting the annealing zone long enough for the piece to anneal.

Dana W.

Jester’s Baubles Fused Glass Designs

http://www.jestersbaubles.com

[FieryVisions]

Thanks so much Paul and Dana! Made corrections and had success

[Author]

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