bullseye annealing check this out!

meadowesky · #1 2006-10-31, 2:22pm

so I ask bullseye directly for an annealing schedule for the new kiln. I am told
"Do you need an annealing schedule for beads? If so, our torchworking instructor heats the kiln up to 960 and holds it there. When she is finished making her last bead and puts in the kilns, she sets the controller to hold for one hour and then cool as fast as possible (not venting, just programming it to cool as fast as possible)."

so is this a good idea?? Seems to me like it would defeat the purpose of annealing to cool it so quickly???

Any input appreciated

barb · #2 2006-10-31, 2:27pm

Brandie,

I use a Toolbox that is programed so I have never thought about it but I use Bullseye and my kiln holds at 960 - then when I hit program [after I am finished torching] it holds at 960 for 2 hours, ramps down over an hour to 750, holds for one hour then ramps down very slowly to the end - I think like 1 degree a minute. Because this is a fiber kiln it does not hold the heat if turned off and the slow process is important. I would never ramp down at any stage rapidly.

Barb

squid · #3 2006-10-31, 2:29pm

I would definitely do a controlled cooling at least past the strain point, which is in the 700s - don't remember specifically. If it is a brick kiln, below that you can shut it off and just let it cool.

For a fiber kiln, I would control down to at least 500 or lower.

Having said all that, if you kiln is in the garage like mine, in the winter I control cool down to 300, as it is cold enough (i think) to thermal shock my beads.

meadowesky · #4 2006-10-31, 2:55pm

I love bullseye but I thought it rather odd that they would recommend this. thanks for the feedback!

Ironmountain01 · #5 2006-10-31, 2:57pm

Quote:

Originally Posted by barb

Brandie,

I use a Toolbox that is programed so I have never thought about it but I use Bullseye and my kiln holds at 960 - then when I hit program [after I am finished torching] it holds at 960 for 2 hours, ramps down over an hour to 750, holds for one hour then ramps down very slowly to the end - I think like 1 degree a minute. Because this is a fiber kiln it does not hold the heat if turned off and the slow process is important. I would never ramp down at any stage rapidly.

Barb

So that's why my fracking bullseye was cracking......

bclogan · #6 2006-11-01, 10:42am

It could be that their kiln is a nice heavy-duty brick kiln that cools off slowly anyway. I know with MY kiln (fiber) that would NEVER work.

Feldt's Glass · #7 2006-11-01, 10:55am

I have a larger brick kiln and have lost power to it after the annealing and it still took over 5 hours to cool down. They may think you are using a brick kiln. I wouldn't expect that answer from them though.

MichalAnn · #8 2006-11-01, 12:49pm

The schedule for Bullseye will be esentially the same as for Effetre. Yes, they have a different COE but the size of beads is so small that it is still essentially the same. Garage at 960-965 degrees while you are working. After last bead is inserted, hold for 1 hour (unless beads are larger than
3/4" and then adjust accordingly.) Ramp down at 100 degrees per hour to stress point of 750 degrees. If your kiln is brick, turn off. If not, cool slowly so as not to thermal shock--app. 300 degrees/hour. DO NOT check in kiln untill temp. is below 100 degrees. Hope this helps. BTW, the response from Bullseye seems crazy. Maybe they only make really small beads.
Michal Ann

Bonnie Celeste · #9 2006-11-14, 8:45pm

Hi there,

Well, I am that instructor at Bullseye and to set the record straight...
I usually program the kilns (Paragon Calderas, 2 students/kiln) to hold at 960 (or a little hotter due to the particulars of these kilns) and then continue to hold for at least an hour once the last beads are in and then ramp down to 500 degrees at the rate of 100 degrees per hour. THEN as fast as possible to room temperature with the kiln cooling at its own insulated rate.

You're absolutely right to question that other (odd) schedule and sorry for any misinformation or miscommunication. I'll review this schedule with my coworkers to make sure they're passing along good information.

It's great to see good advice on this board.

Bonnie

pam · #10 2006-11-15, 5:36am

Hi Bonnie, Thanks so much for clearing that up, and thanks for reviewing it with your co-workers. People who know perfectly well how to anneal larger glass don't sometimes realize the peculiarities of annealing tiny glass beads. It's not size that counts, but what we have done to that tiny piece of glass that makes it really necessary to anneal them.