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Using prismatic glass to trap air bubbles

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Using prismatic glass to trap air bubbles

Postby Katie » Tue Sep 15, 2009 2:35 pm

I recently purchased a new platter (mold #8929) and was thinking of taking 2 sheets of clear prismatic glass and facing them criss/cross to each other and fusing them together to create a bubble pattern and then slumping with the new mold. I have not used prismatic glass before. Should I follow a normal firing schedule or is there something different I should be doing to be able to get an even bubble pattern? My normal firing schedule for 2 layers is this:

400 degrees an hr/ to 1000 - hold for 10 minutes
600 degrees an hr/ to 1250 - hold for 60 minutes (bubble squeeze)
AFAP to 1480 degrees - hold for 20 minutes
AFAP to 960 degrees - hold for 30 minutes
150 degrees an hr/ to 700 - off
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Re: Using prismatic glass to trap air bubbles

Postby marykaynitchie » Wed Sep 16, 2009 3:09 pm

Hi Katie,

We asked our instructor/technician Bonnie for a recommendation, and here is her advice:

"An even bubble pattern will happen naturally within the grid formed by prismatic sheet glass. One observation with this technique is that sometimes the bubbles on the perimeter are ever-so-slightly smaller - as some of the air escapes before the edges seal. This is also where the grid is more likely to have an opening, an easy escape route for the air. Overall, the bubble pattern is a pleasing grid and the bubbles themselves are larger and farther apart than with our other textured sheet glasses.

For firing, I would suggest to shorten the bubble soak to 30 minutes and possibly drop the hold at process temperature to :10. The reasoning here is to back off on the bubble squeeze and still provide enough heatwork to achieve nicely formed bubbles and edges."

Hope this is helpful--good luck with your project! Let us know how it turns out.

Mary Kay
Mary Kay Nitchie
Bullseye Glass Co.

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