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-   -   Batch annealing vs stress (http://www.lampworketc.com/forums/showthread.php?t=308312)

beadforever 2018-11-19 10:07am

Batch annealing vs stress
 
I have some beads I received form a friend which were never annealed. I plan on batch annealing these ; but my question if the beads have stress from not being annealed yet and after the fact they get proper annealing is there not a goodly chance they may still break sometime with a temperature change from any stress that was from when cooled at the time after making and than cooled in a fiber blanket. Anther words if a bead form stress in it won't some stress remain in the glass even if annealed? I realize the beads will be better annealed , I just consider this a possible tho
ught.

beadgal 2018-11-19 11:39am

I think any stress will show up right away after annealing anyway. If you start with cold kiln and ramp up slowly, that should do it.

beadforever 2018-11-19 12:03pm

I guess I did not make it clear what I am referring to or see as a possible problem . What I mean is even if one batch anneals the beads properly if the glass form stress in it will that stress still remain even after a batch anneal as stress is formed through the cooling stage whether the glass cooled in a kin , fiber blanket, or annealing bubbles . annealing would not remove that stress in the glass only stop stress form forming if done properly. Would my assumption be true ??

Three Muses Glass 2018-11-19 2:45pm

Not really. Annealing properly will relieve stress in the glass but it will not relieve cracks, incompatibility or other flaws that may show up. Once annealed, glass doesn't really have a stress memory.
Like beadgal said, ramp up slowly.

KJohn 2018-11-19 8:09pm

It will relieve the stress but not any cracks that have formed from that stress. So the sooner, the better :)

rainygrrl 2018-11-20 12:35pm

I agree with Rebecca and Kristin. If th beads had gone directly into the kiln, they would have had stress too. Ramp up slowly, anneal as usual.

glassmaker 2018-12-19 4:11pm

No. As the others above have said, if the beads are annealed and cooled properly, it doesn't matter what stress might have previously been in them. They will now be properly annealed, assuming they didn't crack while being heated to annealing temp. (Seems redundant, but that appears to be what you're asking.)

On the other hand, if they were made with incompatible glasses, it doesn't matter how much annealing they get. There will always be residual stress in them.

mikefrantz 2018-12-23 10:30am

Brand New Kilns under $200?
 
Has anyone though of using the new 'air fryers' as a kiln? The temperature is well over the annealing temperatures required.

Any thoughts on this crazy idea?

Mike

ESC 2018-12-23 4:25pm

Ok Mike, ya got me! I was like "what?!". Is this a refrain of the old 'annealing by tappan' story?


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