slab layer firing

[betsybirth]

I have fired a 8 x 10 slab 12 mm thick and now I want to tack fuse small pieces on top. I used the 12 mm tack/fire polish schedule and the pieces are not soft edged enough. Your schedule doesn’t go past 12 mm and I am realizing that I should of used a 36 mm thickness schedule. I am not sure how to get there. Of course I am new at this firing business! Bullseye 90 coe BTW. I am confused about how to read the annealing schedule.

[Paul Tarlow]

See if this helps:

https://www.bullseyeglass.com/images/stories/bullseye/PDF/other_technical/2019b_annealing_thick_slabs_fahrenheit.pdf

[betsybirth]

Thanks Paul. I did try that the decorative pieces on the top did not contour enough. The edges did not round out. The pieces are 3 mm thick with one 4 mm on top of the 12 mm slab. The annealing chart for 38 mm ( uneven pieces suggest to double thickness on chart only goes to 900 degrees which seems too low for a contour tack. Sorry I am truly a novice at firing these thicker pieces.
I first used the tack fuse schedule (Bullseye) for 12 mm, then realized that the slab plus the uneven pieces are really probably 16mm thick. The Bullseye schedule doesn’t go higher than 12 mm. Any ideas?

[bigtexun]

Paul’s chart is for annealing only. You aren’t going to be fusing or firepolishing at the annealing temperatures. I think Paul misunderstood the information you were looking for.

Go to the bullseye site and find the chart named “Basic Firing Schedules for Bullseye Glass 2020”. If you look there you will see the tac-fuse/fire-polish is around 1400*f (760c).

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