Annealing Chart

[e. mort]

I have been using this chart for a long time, and can't remember where I got it. So if it is yours and I shouldn't be posting it please let me know and I will remove it. I have used the bullseye and Moretti annealing schedules successfully. I have yet to try out the boro schedule.

Eric

[e. mort]

I have been using the boro schedule for about a month now so I can vouch for it as well.

Eric

[pam]

Hi Eric, I think somewhere on the Bullseye website it states their annealing temp is 968 (not the 940 stated in your chart). But what I don't understand, looking at the chart I see a hold time of 30 minutes for 1 inch. Generally accepted is 15 minutes a quarter inch, but if you slowed down the cooling that wouldn't matter, which brings me to my real question: T4 under the 1 inch says 36, does that 36 represent cooling at 36 degrees an hour? If so, then the holding for 30 minutes wouldn't be bad. Just curious what it means.

I have seen this chart somewhere before, but can't remember where.

[Tanya]

Great chart Eric - last week I was looking all over for a listing of the working point temps for soft vs. hard glass and couldn't find one.

[e. mort]

I have had this chart since 1996, I think. I don't know if Bullseye has changed since then or not. It was emailed to me by a guy who has a hot shop up in the Seattle area, but I can't remember who.

The 36 refers to 36 minutes to ramp down from annealing temperature to strain point temperature.

There are so many variables in the annealing process (kiln construction, heat of the piece when it goes into the kiln, color of the glass, placement of the pyrometer, location of the heating elements, etc.) that I am not sure anybody can point to a truly 100% accurate annealing chart for any glass. However, if bullseye recommends something else for their glass then people should probably follow it.

Eric