About the Collaglass Technique
Each piece begins with a collage: Starting with a sheet of cardboard, I glue on layers of textured papers, string, wire etc to create a picture in relief. This collage can take well over a week to complete, depending on size.
The finished relief collage is given a good coat of varnish, which protects it when I pour on hot rubber to create a mould. This rubber mould allows me to make a limited edition run, as it can be used several times.
To cast the collage in glass, I then need another mould that can survive the temperatures in the kiln - above 800ºC. For this I use a special plaster mix which has additions like glass fibre, silica and grit. This is poured over the rubber mould, to pick up all the detail.
The final casting stage is to fill the plaster mould with lead crystal glass. This comes in ingots - called billets in the glass world. As the kiln comes up to temperature, the glass melts, filling the mould and flowing into the details of the collage. The kiln is then cooled slowly, which prevents the glass cracking.
It is always a nerve-racking event opening the kiln after a firing: Even after taking all precautions, a mould might crack, or the glass may develop an ugly bloom during the firing process. Dealing with these problems - and sometimes having to start again - is part of any kiln worker's everyday routine.
Once the piece is taken out of the kiln, the plaster mould is carefully broken away to reveal the glass. Great care must be taken at this stage - the glass may have sharp edges that will need grinding away. The Collaglass is then thoroughly cleaned to remove any clinging plaster before being acid polished - to bring out the sparkle.
