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bubbles

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bubbles

Postby martha » Thu Jan 28, 2010 1:19 pm

i am pre-fusing 3 mm sheets of tekta and white sheets with various powders. i full-fuse these to make the surface as smooth as possible, because i then stack two or three of the pre-fused sheets and fuse them together. sometimes i get a bubble (the ugly, amoeba kind, not the pretty, roundish kind) in the final piece, depending on how much of the powder i have used on the pre-fused sheets. is there some way to continue to get the rich color of the thicker application of powder and yet not end up with ugly bubbles in the final piece?
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Re: bubbles

Postby artglasstash » Thu Jan 28, 2010 7:08 pm

Normally soaking at the highest fusing temp. ..... the bubbles will eventually emerge......especially the larger amoeba type.......it can take awhile though sometimes up to 30 minutes or more......I'm a real voyeur when it comes to my kiln, which not many people seem to be anymore, if you watch it could happen in less time than you expect........ good luck martha :)
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Re: bubbles

Postby jestersbaubles » Thu Jan 28, 2010 7:56 pm

Look on the 'net for instructions on doing a bubble squeeze. It essentially consists of a hold at about 1000, very slow ramp to... 1250-ish I think with another hold (this is all off the top of my head), and then AFAP to full. Like I say, off the top of my head so check the temps & hold times, but essentially the hold at 1000 and the very slow ramp & hold to 1250 will give the glass time to settle and most of the bubbles will work their way out.

Dana W.

www.jestersbaubles.com
Dana Worley Fused Glass Designs
dba Jester's Baubles
http://www.jestersbaubles.com
http://www.jestersbaubles.blogspot.com
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Re: bubbles

Postby marykaynitchie » Fri Jan 29, 2010 9:43 am

Hi Martha,

Your project seems similar to the project in Bullseye's TipSheet 3: Working Deep, and the instructions there address the issue of stacking sheets on which frits or powders have been pre-fired. You will find suggestions for helping the bubbles escape, both through the glass layup (arrangement) and the firing cycle.

Download the pdf file at this link: http://www.bullseyeglass.com/pdf/techno ... eet_03.pdf

The TipSheet includes some recommended fusing cycles. You could start with these cycles, take notes on your results for each firing, and come up with cycles that work very well for your particular kiln and project.

Mary Kay
Mary Kay Nitchie
Bullseye Glass Co.

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