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RARE Westmoreland Milk Glass BEADED SAUCER Paneled Grape Design 1960s US $6.99 |
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VTG 70s 50 EXTRA LONG Flapper ART RARE GLASS BEAD NECKLACE 21 US $14.98 |
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RARE VINTAGE BEAUTIFUL 54 GREEN ART DECO FLAPPER Glass Bead NECKLACE US $14.79 |
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Vintage Antique Rare Italian Coral glass beads Necklace US $9.99 |
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Vintage Rare Myiuki Kernel Matte Glass Beads Japan US $2.26 |
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VTG 50 Flapper ART DECO RARE GLASS BEAD NECKLACE 8 US $12.98 |
Can I reshape a Glass piece (bead) in a kiln without having it crack when it cools down?
I was thinking of reshaping some Glass beads that I have. But I don't want to end up with ones that will crack or explode.
November 3rd, 2009 at 10:49 pm
Glass has to be heated at a moderate rate to keep it from cracking going up and it needs to be annealed coming down. That means that once it has melted/sagged/fused to the shape you want, you first want to chill the glass to about 1000F to keep devitrification from damaging it. Then you hold at the annealing point which varies with the glass, but is usually near 900-950. The thicker the beads are, the longer the kiln has to be held at the annealing point to let the strains of abrupt cooling and the slower the lowering of the temperature. Normally, glass requires an electric ramping controller for annealing. If the kiln has a bunch of insulation so it drops temp slowly when off, then you might lower the temp by 50 or 100 degrees F lower, then waited 1/2-1 hour, then lowered again and waited until you got down to about 600F then just turn it off. The larger the bead, the longer time it takes or smaller steps. A thick 1" bead might normally soak an hour and take 5 hours to be cooled. (estimate, check with Bullseye glass or other fusing sources http://www.warmglass.com for details on 3D small objects. I normally deal with flat or bowl shapes.