Glass fusing is the technique used to join glass pieces together by partly melting the glass at high temperature. The fusion process requires multiple pieces of glass. The heating is commonly undertaken in an electric kiln. Instead of fitting glass together using a lead solder, two or more pieces of glass are laid on top of or overlapped on each other and are fired at temperatures ranging from 1100 to 1600 degrees Fahrenheit (750 to 850 degrees Celsius).
Fused glass window
It is important to realize that glasses with different coefficients of expansion or viscosity cannot be fused together. Upon cooling or after a period of time, the fused piece will crack. Many people who work in glass fusing restrict themselves to one brand of glass (e.g. Bullseye Glass, Uroborus, Baoli, Spectrum or float glass) which is guaranteed to be compatible with any other fusible glass offered by that particular maker Moulds can also be used in glass fusion, this is a process called slumping, glass is laid over the mould (generally made of ceramic or metal) and forms to it creating pieces such as plates and candle holders.