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One of my first glass works was an experiment in enhancing devitrification.  I really wanted to see how far I could push it, and obtain strong crystallization patterns, so I intentionally fired for a longer time at low temperature (or, at least, at that time I thought I was holding for a long time).  The glass is Uroboros cullet from CRLoo, which was actually the trimmings from clear Uroborus sheet glass at the time, COE 90 (Bullseye compatible).

The casting is a 22″x22″, about 3/4″ thick.  Here is the firing schedule.  At the time (around Fall 2010) I was pretty conservative about the annealing and cooling times.  Now I tend to go by the Bullseye Annealing Chart for Thick Slabs, which gives more accurate firing times.

Ramp (degrees F / hour) Temperature (F) Hold (hours)
200 350 4
200 1100 1
100 1250 2
100 1400 1
Full 930 8
10 800 0
20 700 0
50 300 0

I also added some copper wire, around 32 gauge (taken from a stripped Monster Cable speaker wire).  Here is an image of the final piece.  The pattern and bubbles are fantastic!

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Look more closely at the detail.  There is much detail in the bubbles, and the white lines are due to devitrification (crystallization) along the edges of the glass shards.  Wonderful, I love it!

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For measure, here is an even closer photo, where we can see an image of the Universe and constellations.’

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