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bubble in 10x10

Posted: Sun Nov 01, 2015 10:20 pm
by jerry keller
I do not like to use fibre paper, and put a 10x10 1/8" piece with fruit onto the kiln washed shelf. I ran a program that was for fusing from Youghegheny, and the glass ended up with a big bubble in the almost center. I've heard of putting small chips of glass in the four corners, to ease the glass down onto the shelf, and will try that. Any other ideas would also be helpful.

The ramp was
Full fuse
300-800-10
300-1120-10
200-1250-10
500-1560-10
9999-1020-30
100-800-30

Re: bubble in 10x10

Posted: Mon Nov 02, 2015 3:29 pm
by Valerie Adams
Jerry, a photo and type of glass used would be really helpful, as oftentimes layup contributes to large bubbles forming (I'm thinking volume control).

Also, was it just a single layer of glass with the fruit shapes here and there on top? Again, that would be problematic with only a single layer base.

I also incorporate a bubble squeeze in most of my firings, which is ramping at 50° per hour between 1150° and 1250°, then holding for anywhere from 30 minutes to an hour before heating to final temperature.

Your 1560° top temperature is way hot too. I seldom fire above 1440° for a full fuse.

So, lots of questions!