Annealing Pattern Bars

[Goldfinger]

Hi Everyone: I am thinking about a project involving a form of pattern bars. The piece will be roughly 4 1/2" long- 1 1/2" high" - 1 1/4" wide.
According to the complicated Bullseye schedule, the whole process from start to finish is 23 1/2 hours.(firing and annealing) Since this would be my first project of this type- I would like to stay with the kiln in case something goes awry. The question I have is this- what would happen if I just turned the kiln off at 600F after having gone through the firing and annealing stage and let it cool overnight and check it in the morning? Is it really neccesary to cool from 600F to 75F according to the schedule since it's already gone through the most critical part?

Thanks

Steve

[charlie]

it depends upon your specific kiln. a fiber kiln would cool much faster than a brick kiln, which is faster than a ceramic kiln.

[Judy Schnabel]

Steve,

Lisa Allen had a marvelous picture tutorial in the on-line glass magazine. I followed her instructions (I don't believe they involved a 24-hour schedule) and my pattern bars turn out beautifully.

Try to do a search on Lisa Allen or maybe someone will recall the name of the magazine.

Judy

[Nancy Juhasz]

Here is the link for the online pattern bar tutorial by Lisa Allen.

http://www.ebsqart.com/Education.asp?Co ... used+Glass

I hope this link works.

Nanc

[Brock]

As long as your kiln cools relativly slowly at the bottom end, you'll be fine.
Firing schedules that someone has worked out for you are great to have, but can't always be used. In classes, we don't have the time to properly anneal pattern bars. A quick rule of thumb is to anneal 1 hour per 1/4" of thickness. I never do in classes, because of the time element, and because I know we're going to cut them up the next day. In fact, most of our pattern bars only get 1-2 hours annealing, and they're all over 1" thick. There IS some breakage doing this, but it's a matter of expediency, and most of the stress is relieved when you cut the bar. The individual slices are still not annealed, but they are very unlikely to break now. A good anneal on the finished piece IS required. Brock