New Kiln - glass cracking
Posted: Mon Jan 07, 2013 7:43 pm
I've recently purchased a Paragon GF kiln after two years firing with Quick Fire kilns. I'm trying to figure out at what stage I messed up two fires. I've had one that worked on smaller pieces in the new kiln.
Bulleseye COE 90 glass on all glass except Austin Thin Films 90 Tye Dye accents
Base layer cobalt
Mid Layer frit and tye dye and some stringers
Top Layer Clear
Fire Schedule:
Step 1: Fire at 300 per hour until 900 and hold for 45 minutes
Step 2: Next go to 1250 and at 1250 go up 100 degrees holding for thirty minutes
Step 3: Target temperature 1475 with 10 minute hold
Step 4: hold at 960 for 60 1 hour
Step 5 allow kiln to cool 50 degrees per hour until reaches 800
Step 6 Allow kiln to cool 100 degrees per after it reaches 700
Hopefully, I've attached a picture of what occurred following this schedule. I'm seeking a suggestion on where to modify the schedule. The cracks I've seen before when pieces cooled too quickly in the quick fire. The pocket of shattered glass (not just cracked is different). Any comments or ideas on what to try differently would be appreciated.
Bulleseye COE 90 glass on all glass except Austin Thin Films 90 Tye Dye accents
Base layer cobalt
Mid Layer frit and tye dye and some stringers
Top Layer Clear
Fire Schedule:
Step 1: Fire at 300 per hour until 900 and hold for 45 minutes
Step 2: Next go to 1250 and at 1250 go up 100 degrees holding for thirty minutes
Step 3: Target temperature 1475 with 10 minute hold
Step 4: hold at 960 for 60 1 hour
Step 5 allow kiln to cool 50 degrees per hour until reaches 800
Step 6 Allow kiln to cool 100 degrees per after it reaches 700
Hopefully, I've attached a picture of what occurred following this schedule. I'm seeking a suggestion on where to modify the schedule. The cracks I've seen before when pieces cooled too quickly in the quick fire. The pocket of shattered glass (not just cracked is different). Any comments or ideas on what to try differently would be appreciated.