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Re: Faulty glass? or faulty user?

Posted: Sun Feb 17, 2008 8:37 pm
by Barbara Muth
frizzygirl wrote:Hiya

Thanks Tony, sorry trying to be quick before my laptop battery dies.

Its 222C to 677C with a 30 min hold.
Then 333C to 777C with a 6min hold.

Regards
Tracey


that would be 400 dph to 1250F, hold 30
and then 600 dph to 1430 F, hold 6

So a couple of thoughts... If your base was one layer thick you were going to have problems with volume control at that high a temp. If you wanted to just tack the pieces together you could have done so at a lower temp, say around 1300 F or 700 C. You are ramping up way too fast which is why the piece thermal shocked. And that fast ramp will trap air in a piece as well. You need a bubble squeeze.

Instead try:
200 dph F to 1000F (111 dph C to 538C)
50 dph F to 1250F (28 dph C to 678C)
300 dph F to 1350, hold 15 (167 dph C to 732C)
and then anneal as recommended by your glass manufacturer.