2nd stage soak tempurature

[drewspuppet]

what's the temp for setting boro glass when you drop to 9 hundred something to let the middle cool after you've annealed for your 1050 or whatever time?

[slave]

you mean the strain temp? which is 960.

[slave]

or check this out
thanks n8
http://www.glassartists.org/Gal14595_How-To_Anneal_Your_Glass.asp

-aaron

[jello]

bob (snodgrass) told me 15 min per 1/4 inch. and so far so good, i always flame anneal before i put it in the kiln just for shit and giggles. but rule of thumb is 15 min per 1/4 inch in the kiln from what i understand.....

[Mike_Aurelius]

15 min per 1/4" isn't a bad idea for hold times at annealing temp, but meaningless below the annealing temperature.

I always do a slow drop from annealing to strain point, usually about 2 hours, then a brief hold at strain point (usually about 5 minutes) to allow the kiln to stabilize a bit, then the controller does a shut down at that point and cools to ambient (room temperature) normally, usually about 4-5 hours.

Can we find a different word or description of the process instead of "flame anneal"? Flame stabilze, flame equalize, but please, not flame anneal, ok?

[puddletown]

why find a different term? isnt that what its called?? that is what I always knew it as.
In Homer Hoyt's book "Glassblowing" that is what it is called. I'll stick with Homer.

[Izzy Spun]

The hoyt book may refer to flame annealing, but that is a misnomer. You are not actually annealing anything in the flame. You can stabilize the piece, and stop it from cracking perhaps, but the actual process of annealing requires the piece to be held at a consistent temperature of 1050 for a length of time directly dependent upon the actual volume of glass. If I remember correctly, I learned to anneal for 20 minutes per cubic centimeter of glass? That may be it, but I'm not sure.

[puddletown]

well if you do it right, you can pretty much hold the piece at a constant temp for a period of time, then when you take it out of the flame, it all cools down at the same time. Sure its not the same as putting it in the kiln, but I have always known it as flame annealing.

we could make a poll, and see if we should change the name.

[Islandglass Man]

I have to disagree with Mike the term Flame Annealing is correct. It is a standard procedure for all scientific glassblowers and a must when making complicated apparatus. When done correctly the item will show no strain. Granted it is time consuming and takes some skill to get the right temperatures.

The only time this technique will not work well is when you have to anneal something like a 1.5" marble or heavy multiple ring sealed items but flame annealing will keep these items from cracking until the item is finished and kiln annealed. This is similar to flashing in a glory hole.

The annealing flame is easy to adjust on a cc torch.

Bear

[Swampy]

keep flame annealing, it sounds sensible to me.