Fused glass is a term used to describe glass that has been fired (heat-processed) in a kiln at a range of high temperatures from 593º C (1100ºF) to 816º C (1500ºF). There 3 main distinctions for temperature application and the resulting effect on the glass.
All of these techniques can be applied to one glass work in separate firings to add depth, relief and shape.
Most contemporary fusing methods involve stacking, or layering thin sheets of glass, often using different colors to create patterns or simple images. The stack is then placed inside the kiln (which is almost always electric, but can be heated by gas or wood) and then heated through a series of ramps (rapid heating cycles) and soaks (holding the temperature at a specific point) until the separate pieces begin to bond together.
While fused glass techniques are generally used to create glass art, glass tiles and jewelry, the slumping process allows the creation of larger, functional pieces like dishes, bowls, plates and ashtrays. Producing functional pieces generally requires 2 or more separate firings; one to fuse the glass and a second to shape it.
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Since the 1970s, more hobbyists have focused on using kiln-fused glass to make beads and components for jewelry. This has become especially popular since the introduction of dichroic glass.