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fibonacci plate full fuse schedule

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fibonacci plate full fuse schedule

Postby diana.owyang » Fri Nov 18, 2016 8:27 pm

I used the fibonacci instructions to cut Bullseye glass. The piece was placed in the middle of a primed mullite shelf in my Skutt GS22ClamShell kiln with the solid 14cm x 40 cm on the bottom and the cut pieces on top. Smooth sides faced up on all pieces. The full fuse firing schedule followed was the recommended one from Tip Sheet 7 (400F to 1225F hold :30, 600F to 1490F hold :10, AFAP 900F hold 1:00, 100F to 700F hold :00, AFAP to 70F hold :00.) The attached photo shows large bubbles along one side of the fused piece.

20161113_145332 (800x450).jpg

Perhaps I should add a pre- bubble soak and make segment 1 300F to 1150F hold :30. Or...perhaps I could increase the time of Segment 1 (400F to 1225F) to hold for 1:00. Any ideas?
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Re: fibonacci plate full fuse schedule

Postby marykaynitchie » Mon Nov 21, 2016 1:52 pm

Hi Diana,

I think your initial heat was too fast for your kiln. Also, I think you can do your bubble squeeze at a lower temperature. Perhaps 300°F/hr to 1200°F and hold for 30 minutes.

A helpful free article to read: "Volume and Bubble Control" http://www.bullseyeglass.com/methods-id ... ntrol.html

A helpful video available in our subscription series: "Beating Bubbles" https://videos.bullseyeglass.com/videos ... g-bubbles/

Good luck on your next one!

Mary Kay
Mary Kay Nitchie
Bullseye Glass Co.

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Re: fibonacci plate full fuse schedule

Postby jestersbaubles » Tue Nov 22, 2016 12:07 pm

The layout of the design, by its very nature, is one that will trap bubbles -- You are taking sections of glass and capping them, which has a great potential for trapping air under the cap (especially if the sections of glass are not really tight fitting).

A few things to consider trying:

* Add a bubble squeeze. Here's my usual squeeze: Ramp appropriately to 1100 deg F, hold 30 minutes, and then ramp 50 deg/hr from 1100 to 1250, hold 60 minutes. Continue as usual after the long hold.

* Fire on fiber paper, rather than a kiln shelf. Air is more likely to escape from under the piece with porous fiber paper as a base. Given the linearity of the location of the bubbles, I wonder if there is a slight depression in the shelf? (if so, the fiber paper would help)

* Reverse the layout prior to firing -- clear on the bottom and top with the pieces. Flip & re-fire if you really want the clear on top with the crisper lines.

Huh... wait, now that I read again, you DID put the clear on the bottom and pieces on top. Ignore #3, but that might be useful info for someone else :mrgreen:

Another thought... 1490 deg F is pretty darned hot for a full fuse. If your kiln fires hot, then any small bubbles that would normally "add character" at a lower temperature could become a big problem. I would try reducing the heat 25-30 deg F.

Best, Dana W.
Dana Worley Fused Glass Designs
dba Jester's Baubles
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Re: fibonacci plate full fuse schedule

Postby ejgiebel » Mon Dec 19, 2016 2:44 pm

Looking at the piece, it appears you used a Collage sheet, which is the brand name for "trapped air bubbles". I made my better half a set of 16 plates from some of these sheets, it took me until the last batch to figure out how to fire them without getting a ton of bubbles. If I was going to do something with one of those sheets again, I would:

1. Fire the Collage sheet with the stringer and confetti side up, maybe filling in the bigger holes with some clear powder. This will definitely fix the bubble problem, but you'll lose the depth of the detail being in the middle of the piece.
2. Fire the Collage sheet on the bottom layer, stringer/confetti side up, and DEFINITELY fill (by sifting clear powder) the Collage sheet, put the bottom layer on top, ramp at appropriate schedule to 1100 degrees, then go 50 degrees and hour to 1250 and hold for 60 minutes, then continue on. Of source, this will necessitate refiring the piece a 2nd time after cleaning or sandblasting the bottom, then flipping and refiring. The 2nd time does not required the bubble squeeze, in fact you can just take it to a fire polish if you want.

Option 2 gives you a way to fill the voids in the collage sheets with clear powder. You can't go slow enough on a bubble squeeze to get all the voids in those collage sheets to fill in without using some clear powder. In your design, clear isn't necessary, you could use powder to match the back sheet as well, I just keep clear on hand for just this sort of thing.
Ed Giebel
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