There are many ways to make a mould and the best way to approach it is to assess certain requirements of your project before you begin:
- How fragile is the master (original artwork) and can you afford to lose/damage it in the moulding process? It is difficult to completely preserve an original artwork when taking a mould if the original is very delicate or made from wet clay or plasticine materials. Does the object have many undercuts and overhangs?
- Some objects are more complex to mould than others. If you have a spherical shape or a simple pattern you may only need a one or two part block mould. More complicated objects may need a skin mould with a multiple-part jacket or ‘mother’ mould.
- What will the final casting be made from? Different moulding materials work better with different casting materials. For example: an alginate mould tends to work better with plaster casting; different silicones accept different resins.
- How many castings/editions do you require? Your moulding material will dictate how many castings you can extract. Alginate moulds will only make 1 or 2 casts; a good silicone mould can produce hundreds.
| Alginate | Quick curing time. Excellent for life casting. Best used with plaster casting. Deteriorates very quickly (24hrs if not kept moist). |
| Plaster | Good for inexpensive mother moulds or jackets when used with scrim. Non-flexible, may require several parts to mould even simple shapes. Requires good release and sealing agents when not using ceramic slip casting. |
| Silicone | Versatile, and very flexible for both block moulds and skin moulds. Comes in various shoe hardness. Can accept a variety of casting materials. Completely non stick. Can make multiple casts. |
| Fibreglass | Often used for moulding large simple shapes. Very strong and light weight. Can be used many times. Requires release agent. Fairly inexpensive. |