Handcrafted lampwork beads are a popular jewelry component. You'll find lampwork beads in beaded necklaces, bracelets and other jewelry. The jewelry is sold on the Internet and in local stores where jewelry artisans sell their creations.
The quality of any handcrafted item is equal to the expertise of its maker and lampwork beads are no exception to that rule. Choose beaded jewelry in a style you like, but remember that style isn't the only thing you must consider when you buy handcrafted lampwork beads.
I don't understand all the physical and chemical reasons why molten glass behaves as it does, but I understand the concept enough to explain the basics of lampwork beadmaking.
Lampworkers use a torch to melt the tips of colorful glass rods. As it melts, they wind the fluid glass around a mandrel, a narrow stainless steel rod. Later, when the bead is removed, the space occupied by the mandrel becomes a hole in the center of the bead--the hole used to string it onto jewelry.
Glass cools from the outside in and the outer layers shrink as cooling takes place. Bringing a bead out of the flame and leaving it in the open air allows the outside of the bead to cool rapidly around its molten interior. A stress point develops between the cool, shrinking glass and the hot center. The stress can cause a bead to crack, either immediately or at a later time.
It's necessary to cooling the beads slowly
To prevent cracks, beads are cooled in a kiln, where temperatures can be closely regulated. The beadmaker anneals the bead as soon as it comes out of the flame. That means the bead is left to soak up heat in the kiln so that all glass within it is the same temperature.
The soaking temperature is high enough for glass to flow on some molecular level, but not so high that the bead ends up in a puddle on the kiln floor. After annealing, the artist begins to reduce the heat in the kiln, taking several hours to bring the beads to room temperature.
The slow reduction in temperature produces glass beads with fewer stress points, so they're less likely to crack. Very small glass beads are sometimes slowly cooled between layers of insulation. It's not the same as annealing, but the process is usually successful because the small amount of glass in tiny beads cools at a more even rate