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How Are Lampwork Beads Stabilised? |
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Glass shrinks as it cools. Bringing a bead out of the flame and leaving it in the open air allows the outside of the bead to cool rapidly, but its inside is still burning hot. The stress point between the cool, shrinking glass and the hot center begins to grow and often causes the bead to crack.
 To prevent stress and cracks, beads are cooled a kiln, where temperatures can be closely regulated. The beadmaker "soaks" the beads at a high temperature to make sure that all glass within them is evenly heated, then takes several hours to slowly reduce the heat to bring beads to room temperature. The process is called kiln annealing. and it's important to make sure that the handcrafted glass beads you buy from craftspeople are kiln annealed.
Tiny glass beads are sometimes cooled between layers of insulation. It's not the same as annealing, but the process is usually successful because it helps small amounts of glass cool at the same rate.
Stabilised beads are cooled in a kiln or
vermiculite. After slow cooling in vermiculite, the beads are still kiln
annealed in a batch to ensure maximum strength and durability.
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