I model the originals in clay for the small and medium size pieces, and in plaster for the larger ones. From these I make moulds in either fibreglass or silicone rubber, depending on the nature of the piece and its size; and from these I cast in Resin, reinforced with a variety of materials such as fibreglass and steel, and bulked out with a range of filler materials which add strength and stiffness to the cast.
Different surface finishes are achieved by the introduction of various filler materials, in the form of a powder rendering of real metals, stones etc., to the outer layers of the cast. Some of these can be subsequently treated to take on a weathered nature which can add a lot of character to the surface appearance.
These materials are extremely durable and weatherproof, and in most cases easily handled. Where extra weight is required it can be added during the casting process.
The alternative material is foundry cast Bronze. This is very much more expensive, not so much for the cost of the metal as for the very complex and drawn out casting process. It is, however, and always has been, the premier material for castable sculpture. Its proven longevity and the sensuous look and feel of its surface make it the preferred medium where ever possible.