Combing cracked, can I refire to anneal?
Posted: Sun Sep 23, 2012 10:35 pm
I have been working on my first larger combings (18" x 18"). Now, a few weeks after taking them out of the kiln, I have one that is badly cracked starting out from the center. I have another that has just a tiny fracture beginning. I would like to re-fire the one with the little crack and hopefully anneal it properly.
I am using system 96 glass, the piece was in a stainless dam lined with fiber paper on a kiln washed shelf. My original cool down schedule has worked on non-combed 18" pieces before, but not this time. The schedule was:
9999 1650 h30
9999 1000 H10
300 950 h60
100 800 h10
300 300
In researching the problem, I noticed Patty Gray has a schedule for cooling an 18" combing on the Spectrum site that I interpreted as:
heat and comb at 1650, then cool as follows
9999 960 h 4 hours
9999 850 h 2 hours
cool naturally.
My questions are:
1. If I re-fire the combed piece to add a rim or fire polish, do I need the same very slow cool down?
2. If I try to recover the piece with the small fracture, can anyone suggest a heating rate to prevent it from exploding? (I really like the design).
3. Where do I find firing schedules for larger, but not necessarily thicker, pieces?
Thanks for your help,
Sandy
I am using system 96 glass, the piece was in a stainless dam lined with fiber paper on a kiln washed shelf. My original cool down schedule has worked on non-combed 18" pieces before, but not this time. The schedule was:
9999 1650 h30
9999 1000 H10
300 950 h60
100 800 h10
300 300
In researching the problem, I noticed Patty Gray has a schedule for cooling an 18" combing on the Spectrum site that I interpreted as:
heat and comb at 1650, then cool as follows
9999 960 h 4 hours
9999 850 h 2 hours
cool naturally.
My questions are:
1. If I re-fire the combed piece to add a rim or fire polish, do I need the same very slow cool down?
2. If I try to recover the piece with the small fracture, can anyone suggest a heating rate to prevent it from exploding? (I really like the design).
3. Where do I find firing schedules for larger, but not necessarily thicker, pieces?
Thanks for your help,
Sandy