Techniques

My preferred method of forming glass encompasses a number of techniques that can all be subsumed under the term kiln-formed glass. As the temperature increases during the kiln-firing process, the glass passes through a number of different stages which can be exploited for the creative process:

The lowest temperatures are sufficient to soften only the surface of the glass. This effect can be employed to round off any jagged edges or to let enamel, for example, be absorbed by the glass‘ surface.

At slightly higher temperatures, the glass can be formed by bending or slumping, due to its own weight. Or it can even be formed by hand, with the aid of various tools, in an open kiln (for instance by folding flat glass). The latter does, however, require higher temperatures.

Heating the glass further until it reaches melting point it softens enough so that separate glass components can fuse with one another. Fusing is especially well suited for producing flat glass objects consisting of two or more layers of glass, permitting the inclusion of materials such as coloured glass, enamel, or other materials such as metals (oxides, foils, wire) between the layers (inclusions).

In kiln casting (or mould melting) a number of techniques for pouring liquid glass at temperatures above melting point into pre-fabricated moulds, sometimes in combination with other materials, have also been developed. In many cases it will be necessary to break the mould after firing to retrieve the cast object. The mould itself is frequently produced using the lost wax method, which is especially suited to create sculptural glass objects.

Finally, to create hollow, thin-walled glass objects with a grainy, variegated surface, casting moulds are covered with a coloured or colourless coating of glass granulate so that the thickness and position of the glass is altered as little as possible during firing. This method is also known as pâte de verre („glass paste“).