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....Make Glass Beads The "raw" material for bead making... glass rods in all the colors of the rainbow. There are beautiful glasses available from manufacturers around the world. Not all glass is created equal. Care must be taken to only use compatible, that is, glass with the same coefficient of expansion (COE), in a bead. Use of glass with missmatched COE's in the same bead will result in cracks. Glass beads are created on metal mandrels. Mandrels are coated in bead release, which prevents the glass from sticking to the metal and facilitates the removal of the bead. The removed mandrel forms the bead hole. Glass is melted in the flame of a fuel oxygen torch. As the glass melts, it is wound around the mandrel. As the molten glass is added the mandrel is continually turned to "round out" the bead. A variety of tools can be used to poke, prod and coax the glass into interesting shapes. There are endless possibilities for decorating beads. Stingers, twisties, murrini and frits may be applied to the bead. Metal foils and reduction frits cause interesting color reactions depending on the "chemistry" of the flame. The differential rate of cooling between the quickly cooling outer surface of the bead, and the slower cooling inner core can cause stress to form in the bead. This may cause the bead to crack either right away or at some future time. To alleviate this stress, fine quality beads are are kiln annealed to remove stress. The annealing process brings the bead to high uniform temperature, holds the bead at that temperature until the stress is equalized through the bead. The bead is than cooled at a slow controlled rate to prevent reintroduction of stress. |
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