Stone: Many different types of stone may be carved to make sculpture. Stone carvings are unique pieces of work requiring skill and hard work to produce.
Wood: Woods vary in colour, density and texture. Some are easier to work than others and skill is required to bring out the unique characteristics of both the wood and the design.
Foundry Bronze: This is molten bronze metal (an alloy of copper and tin). It is poured into a specially prepared mould by skilled foundry workers. The artist will have made the original sculpture in a different material eg, clay or plaster and the mould will have been made on that original. Bronze is heavy, durable and expensive because of the number of processes and workers involved in it’s production. The artist will choose the final colour of the patination and oversee the finishing processes.
Bronze resin: An alternative to expensive foundry bronze, resin is a mixture of real powdered bronze and polyester resin. It is laid into a prepared mould and strengthened with other materials such as fibreglass. Since no heat is required for this process it is often done in the studio by the sculptor or by a technician. It is patinated in a similar way to foundry bronze and can look identical, but is much lighter in weight.
Other resins: Polyester and other resin can be used to bind many types of inert material. Ground marble and other stones, different metals, larger particles such as gravel or grit, and/or coloured pigments may be included. Clear resins may be used to create works with the appearance of glass.
Clay: There are many different types of clay, a most versatile sculptural material. It can be used to model the original from which a mould is to be made for casting. It is also used to make original works for firing to high temperatures in a kiln to produce: terracotta, generally as an unglazed item; stoneware, which is fired to a much higher temperature thus making it stronger and harder; ceramic, glazed earthenware or stoneware and porcelain, a very fine clay with other additives, sometimes becoming translucent after firing to stoneware temperature. There are many other types of fired clay.
Plaster: Plaster of Paris is most commonly used for sculpture, a strong pure white, fine textured powder mixed with water, which is fast setting and can be coloured as desired. It may be used to make original works of art, or as a construction material for the making of moulds. It is not waterproof and therefore not suitable for outdoor sculpture.
Cement: Cement is a weatherproof material often used for outdoor sculpture. It can be cast in a mould or modelled directly on to a supporting structure. It can be coloured by including pigments into the wet mixture or patinated by application of paints etc. to the finished surface. A very fast setting dark coloured cement, ciment fondu is frequently used for casting. Portland cement is the ubiquitous grey one used by builders to make concrete, it takes longer to set. White cement is sold under various trade names and is pure white. It takes longer to fully harden after casting.
Papier mache: This is made from paper and glue often with incorporated items such as wood, fabric and plant materials. Very large, lightweight and extremely strong structures can be made in papier mache. This material is not suitable for outdoor display because it is not weatherproof.