Bubble Repair?

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Bubble Repair?

Postby Franzeska » Sun Mar 24, 2013 8:52 pm

I fused an 11.5" System 96 Opal Art over a clear base. Even though I thoroughly cleaned both pieces and did a 60 minute bubble squeeze per Spectrum's instructions, I got lots of bubbles. The bubbles did not burst. One is raised on the surface enough that I noticed it immediately; I may not have noticed several others had I not closely inspected the piece because of the one obvious bubble. I flipped the piece over and saw 8 or 9 obvious bubbles in the clear bottom. I read that I could try fixing a bubble by poking a hole in it and filling it with clear frit and full fuse it again. I don't really want to poke a hole in the top and possibly disturb the swirling colors. If I flip it over so that the bubbles in the clear base are now on top, do I have to poke holes and fill with clear frit, or just let (hope) the bubbles escape in the next firing? If I fix the bubbles this way, I'll have to flip it right side up and fire polish it, but that would be okay if it is a better way to fix the problem. I still have to tack fuse tiny frit balls on the top to accentuate the swirls, and then slump it. With all these processes, I don't want to have those pesky bubbles surface later. I'm new to fusing, so I don't know if that could happen at tack fusing, fire polishing, or slumping temperatures. That's why I wonder if I should try to fix all the bubbles, or only the bubbles that have raised the surface.

I've never had a bubble problem before because I try to be careful with preparation and fire conservatively. This is the first time I've used Opal Art glass. Is this something that happens with Opal Art glass from Spectrum or is it just one of those things?
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Re: Bubble Repair?

Postby JestersBaubles » Sun Mar 24, 2013 9:50 pm

Nothing particular to Opal Art. That's a fairly big piece when trying to fuse two flats together. Was it, perhaps, larger than many other pieces you have done that didn't show problems? Is it sufficiently large to be close to the kiln walls on a side firing kiln? That could cause the edges to seal prematurely.

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Re: Bubble Repair?

Postby DonMcClennen » Mon Mar 25, 2013 7:12 pm

Along with the bubble squeeze you need to add the chad(s) described in detail here many times in the past. I am able to fuse2 sheets 22" dia. circles with one chad....no bubbles ever.
Your only choice now is blast or drill out all bubbles add frit or small chunk in each and refire.
Don
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Re: Bubble Repair?

Postby Franzeska » Mon Mar 25, 2013 8:01 pm

Thank you. Next time I will use the chad method. In the mean time, drill, baby, drill (I guess).
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Re: Bubble Repair?

Postby Kevin Midgley » Mon Mar 25, 2013 9:58 pm

don't bother. start over with new glass. drill marks/fills will always show in inverse relationship to the importance of the piece.
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Re: Bubble Repair?

Postby DonMcClennen » Tue Mar 26, 2013 9:40 am

depending on your design repair can work well!
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Re: Bubble Repair?

Postby Morganica » Tue Mar 26, 2013 12:43 pm

Franzeska wrote:Thank you. Next time I will use the chad method. In the mean time, drill, baby, drill (I guess).

Be aware that chads can add marks, too, if you're not careful. If you put a clear chad under many transparent colors, the clear essentially dilutes the surrounding glass, making the piece lighter in that area.

The solution for the dilution problem is to either use a chad of the same color as the glass (or as the top layer), or to make sure that you're putting your chads under opaque glass.

Chads can also change the volume of glass at those points, making a slight bump-out in an otherwise straight line. Whether that's a problem depends on the size of the chad, and whether or not you need an absolutely precise edge without trimming. I trim and edge-grind every flat fuse I make, so it's a non-issue for me.
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Re: Bubble Repair?

Postby Franzeska » Wed Mar 27, 2013 10:35 am

I was really going to drill the holes, which were visible through the transparent bottom disc, but I didn't have an appropriate bit. Because I wanted to get this finished, I flipped the piece and slowly fused again. The Opal Art top layer is now nice and flat, and the bubbles do not bulge out of the transparent bottom layer. I am satisfied with that. I just hope the bubbles don't resurface when I tack fuse the little frit balls to the top or when I slump it.

Morganica - Thank you for pointing out the dilution issue. I went through the dilution lesson on the Bullseye site, so I am familiar with that. Heaven only knows if I would have transferred that knowledge to this situation. I'm an educator, and the latest way to classify the level of learning/knowledge is the student's ability to tranfer learning to a unique situation (not the situation covered in the lesson). I'm honestly not sure I'm there yet. I'm happy if I can follow a set of instructions for a specific situation - like following a recipe. One thing is for sure, if it is true that one way to stave off dementia is to continue learning, I'll be immune to Alzheimer's.

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Re: Bubble Repair?

Postby categ50 » Sat Apr 06, 2013 6:05 pm

I just fired 2 blanks, one 14" and the other 16". I ended up with many bubbles in the center of each, which had shards and stringer design. Clear cap on top of shard area and a bubble squeeze in the fireing. I drilled out the bubbles and filled them with fine clear frit. After a re-fire, they are perfect. But now I put the shard/stringer pieces on the top.
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