What is Glass Fusing?


Fusing is the technique of joining two or more pieces of glass by heat in a kiln. There are different glass fusing techniques. For example, “tack fusing” is a fusing technique in which the pieces of glass are heated until they are just hot enough to stick together and retain many of their own original characteristics. In a full fuse, on the other hand, glass is heated until it becomes molten. Fused glass art can be any number of things: from slumped bowls and platters, to printed imagery, to anything else the mind can conceive and make.


Fusing requires a special type of glass. Specifically, the different glasses you use must all be compatible with each other. We use Bullseye kiln-glass for fusing projects because of its quality and because it's made in the USA.


Many people use the terms “fusing” and “kilnforming” interchangeably; however, that is not entirely correct as fusing is one of many kilnforming methods.


Slumping is a kilnforming process that uses heat and gravity to transform sheet glass into the shape of a mold. One can to create an almost endless variety of forms when slumping glass. When the glass is heated in a kiln and enters a liquid state, the force of gravity pulls it to the floor. In glass slumping, this “floor” is some type of mold. After the heated glass has flowed into the mold and assumed its shape, it is cooled back down to room temperature with an appropriate annealing phase. By the time the glass is fully returned to room temperature the liquid glass will be crystallized into the rigid form of glass with which we are most familiar. Its new permanent shape will be that of the mold. Slumping is a process that is commonly used to make food-bearing objects such as bowls and platters, but with some creativity one can create all kinds of interesting variations.


People also tend to use “kiln-glass” and “fused glass” interchangeably, though we prefer to reserve “fused glass” for finished projects that have already been fired in a kiln and fused with another piece of glass.


We hope this clears up some questions many of you have. If not, feel free to ask!