How
My Kiln Cast Glass Sculptures Are Made
The lost wax process of kiln casting a glass sculpture is time consuming,
expensive and complicated. A brief explanation of the various steps is
as follows:
I start by designing the work through water color drawings and the making
of maquettes of the sculptures. I may make two sizes of maquettes if I
am making a large scale sculpture. Following the maquettes I make the
sculptures to scale. I must first make an armature of metal rods for support;
I then make the model out of clay on top of the armature. Once the model
is complete, a rubber mold with an outer mother mold is made. The clay
is removed from the rubber mold and now we pour waxes of the model.
Once I have the waxes, I can further carve them and clean them up. Now
I add a reservoir (to hold the glass later). Now plaster silica and other
materials are mixed and built up in layers, to make a mold around wax.
The plaster/silica mold is then steamed out, so that it is now hollow
and therefore able to hold the glass. (On large-scale pieces another cement
jacket is also added to strengthen the mold).
The mold is now placed in the kiln. We use a crane to lift the larger
molds. Chucks of lead crystal (the purest glass, imported from New Zealand
and Czech Republic) are then carefully weighed, washed and then placed
into the mold in the Kiln.
The kiln is then programmed to reach 760ºC over a 24hr period. The glass
slumps and flows into the hollow mold, becoming the shape of the sculpture
at that temperature. After being at 760ºC for several hours the kiln is
programmed to come down in temperature at an extremely slow rate form
several days up to a 6 weeks in the kiln depending on the size of the
glass sculpture. Glass will break if it does not go through this long
annealing process.
Once the kiln has reached the end of the program and the mold is at room
temperature again, then the mold is removed from the kiln. At this point
the mold material is carefully chipped away to reveal the glass sculpture
inside. At this stage the glass is rough and is ready for finishing, which
is called cold working.
Cold- working is similar to the sanding of wood or bronze, but it is all
done with a constant flow of temperate to cold water on the glass piece
so that the glass does not get too hot from the abrasion and crack. A
dremmel tool with a diamond bit is used to remove any bumps and excess
sharp glass. The glass sculpture is ground down to have a perfectly flat
bottom. Diamond abrasive pads are used by hand to smooth and polish glass
surfaces; this can take days. The entire surface of sculpture is sand
blasted to unify it and then it is acid etched, which gives the lead crystal
a luminescent polish. Finally cleaned, it is ready to be photographed
and then packed for shipping.
