Modelling and Casting
This is the working method that I tend to use most. Modelling is the reverse of carving in the sense that the form is built up rather than taken down (although after, or during, building up, I might often carve away as well).
The materials I most often use in modelling are plaster, clay or wax. Often other materials or objects might be added to, or worked into the modelling material (e.g. fabric, bits of wood).
Modelling almost always requires an armature (a skeletonic frame) for support. This would typically be made of wood or welded steel and would aim to echo the expected finished shape as closely as possible.
Modelling seldom results in a finished piece of work in a permanent state because of the materials used. Almost all modelled work needs to be ‘cast’ into another material.
Casting is not in itself a method of making sculpture - just of rendering a sculpture into a permanent form (or of making an edition, or run, of several casts of the same piece).
Casting involves making a mould of the original. The mould would usually be made in several pieces of rubber poured (hot or cold) through a case, or jacket. The jacket is made of fibreglass and will support the rubber and keep it in place. It is made by painting fibreglass over a bed of clay laid over the sculpture, one small section at a time. When the whole jacket is complete and the pieces bolted together, the sections are removed one at a time, the bed of clay is removed, the case section replaced, the seams sealed and the rubber poured into the gap left between the sculpture and the case.
When the mould is complete, a cast (or several) is taken from the mould in a permanent material like resin or cement. Resin is the most durable and versatile. While the mould sections are separate and apart, resin (mixed with a metal powder or colourant if required - I use stone dust) can be painted or pasted into the mould sections. If necessary, steel reinforcing rods would be set into the unset resin at this point. When the resin has ‘gone off’, the sections are bolted together and more resin is pasted over the inside of the seams.
If the cast is to be hollow, it will be strengthened with successive coats of fibre-glass. If it isn’t too big, it could be filled with resin mixed with a filler (like dry stone-dust - to disperse the heat generated during setting).
After allowing the cast to cure overnight, the mould is taken apart and the cast removed. An electric grinder is used to remove the seams. The whole surface is then sanded and polished.