bullseyeglass.com • View topic - discrepancy in bullseye annealing documentation

discrepancy in bullseye annealing documentation

For discussion of processes related to using Bullseye glass, including kilnforming and kilncasting, torchwork, blowing and stained glass.

discrepancy in bullseye annealing documentation

Postby coinopz » Mon Mar 21, 2016 10:48 am

Hi, there are 2 documents on the bullseye site that have annealing schedules - the `bullseye glass firing' pdf which shows the steps for firing the glass bull, and the 'bullseye annealing thick slabs' pdf.

The first pdf has a bull that looks around 2-3 inches thick in the thickest crossection - i might be wrong, but it is a fair sized sculpture. When i add up the total time for annealing and cooling (steps 4-8) i get a total of around 32 hours.
The other pdf, annealing thick slabs, shows a schedule for a slab 3 inches thick that is 99 hours. Thats 3x longer than the first document.

Now, the thick slabs document mentions irregular objects should double the anneal times listed. So, if we say that the glass bull is only 1.5 inches thick in thickest cross section, it's irregular shaped, then we double the thickness for the thick slabs document and get a 3 inch anneal/cool schedule of 99 hours.

So, my question is - am i calculating something wrong here? Did the bullseye guys really fire that bull with a 32 hour total anneal/cool time? or did they take much longer to do it?
If they did use the schedule listed in their glass bull document, does that mean i can use a similar schedule for something around the same thickness (eg, a figure sculpture) ?

I ask this because there is a huge difference between the 2 schedules and if i don't need a 99 hour anneal/cool, that would save much time. On the other hand, if I do need it for something around the thickness of that bull, i need to know before i fire these things.

Any insight into this would be greatly appreciated.
I am firing figures that have a max cross section of 2.5 inches thick and many have thin parts .5 inches thick or less. They are all in plaster/silica block molds with an electric kiln that can evenly cool on all sides.
Posts: 1
Joined: Mon Mar 21, 2016 10:21 am

Return to Technique

Who is online

Users browsing this forum: No registered users and 1 guest