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