Firing schedules for thick pieces of glass

It is very important to get the correct firing temperature for your glass projects so that you don't open your kiln, thinking your project is completed, only to discover a broken disaster!  In our own glass studio, we have discovered, the hard way, that we have to slow down our firing schedule when fusing our glass bottles together.  You will find that you not only need to slow down the heating up process, but also the cooling down part too.

We found these great tables below, made by System 96 glass.

*Please note: the schedules below are guidelines only, not strict rules. Times and temperatures may be adjusted based on the nature of your project. To use these schedules for slumping, set the target temperature in the "variable" step to 1235 - 1250 depending on your desired results.

1/2 -inch Thick Step Rate(per hour) Target Temp. Hold(minutes) 1 100 300 15 2 250 1050 10 3 *variable 1500 desired effect 4 as fast as possible 950 90 5 100 800 10 6 300 100 0

*This rate varies based on what you want to accomplish. For instance, heat faster to fire polish, slower to minimize air bubbles.

1 -inch Thick Step Rate (per hour) Target Temp. Hold(minutes) 1 100 300 15 2 200 600 15 3 300 1050 15 4 *variable 1500 desired effect 5 as fast as possible 950 120 6 30 800 15 7 50 700 10 8 250 100 0

*This rate varies based on what you want to accomplish. For instance, heat faster to fire polish, slower to minimize air bubbles.

1.5 -inch Thick Step Rate (per hour) Target Temp. Hold(minutes) 1 100 300 25 2 200 600 25 3 300 1050 20 4 *variable 1500 desired effect 5 as fast as possible 950 180 6 12 800 15 7 24 700 10 8 120 100 0

*This rate varies based on what you want to accomplish. For instance, heat faster to fire polish, slower to minimize air bubbles.

2 -inch Thick Step Rate (per hour) Target Temp. Hold(minutes) 1 100 300 40 2 200 600 40 3 300 1050 30 4 *variable 1500 desired effect 5 as fast as possible 950 240 6 8 800 30 7 16 700 30 8 65 100 0