Reduce/remove micro bubbles in full fused pieces -

Reduce/remove micro bubbles in full fused pieces

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Reduce/remove micro bubbles in full fused pieces

Postby TammyP » Wed Nov 15, 2017 2:31 pm

Looking for suggestions -

I've been working on simple full fused tiles - 2 layers, one being clear. I end up with micro bubbles in the finished piece. Happens with two pieces directly on top of one another, and when I put small clear "chads" under the corners of the top layer. So suspect it is my schedule. I'm using a 150/hour ramp from 900 to 1100, holding 1100 for 30 minutes, then a 250/hour ramp to 1500, holding for 30 minutes before heading back down AFAP to 900 for a 1 hour hold. Any thoughts as to how can adjust anything at all to have a more pristine finished tile?

Also, any thoughts as to a remedy for the fused tiles that have the bubbles - is refusing an option?

Valerie Adams
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Location: Santa Rosa, California

Re: Reduce/remove micro bubbles in full fused pieces

Postby Valerie Adams » Wed Nov 15, 2017 7:03 pm

"Champagne bubbles" are an inherent trait of fused glass. Besides doing a good bubble squeeze (I ramp at 50° from 1150° to 1250° in my kilns), some people sift a very fine layer of clear powder between their layers of glass. I'm talking a single grain thickness. It's easiest to use a blank silkscreen to screen on a single thin layer of powder. Bullseye shows how to do it on their website in one of the tip sheets, I believe.

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Location: Arkansas

Re: Reduce/remove micro bubbles in full fused pieces

Postby Judd » Fri Nov 17, 2017 9:39 am

I understand many people hate bubbles, but I love them. They add character to the piece.
Just my 2 cents.

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Location: East Tennessee

Re: Reduce/remove micro bubbles in full fused pieces

Postby Vonon » Fri Nov 17, 2017 11:22 am

1500 seems a little high to me but don't know if that would make a difference. I use the sprinkled clear powder between the layers method (no chads needed with this) along with a low and slow schedule and no longer get the surface bumps. If you have a smooth surface - embrace the bubbles.

linn keller
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Location: south tx

Re: Reduce/remove micro bubbles in full fused pieces

Postby linn keller » Fri Nov 17, 2017 11:47 am

it sounds like the bubbles you're seeing are in the glass, not coming from fusing the 2 layers together: you're seeing bubbles that were already there, that have moved toward the surface in that layer. bubbles move up (and expand) when the glass is soft and warm enough. if they aren't popping to the surface, leaving little divits, then it's a visual thing. if you want to make them less visible, try lessening your hold time and/or temp at peak (1500 for 30 min). since movement and expansion cease as the glass gets cooler get the temp dropping afap after the fuse is complete. try dropping time and temp again and again til you get to the minimum needed for the amt. of fuse you want, but no more. that will decrease the rise/expansion of bubbles. hope this helps, linn
linn in deep deep south texas

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