Zen and the Art of Prop Making

A silicone mould is much more forgiving with undercuts than one made from fibreglass because they are so flexible. A silicone mould is used more for casting urethane foams and resins to make solid objects. They are excellent for making bottles and glasses and usually have a cut down one side to make it easier to remove the cast. A wooden box or tube is used around the mould to support the silicone rubber when it is filled with casting material. A silicone mould is easy to make but the materials are expensive. You need to balance the size of your object with the size of your wallet. That being said they are robust moulds and can give many impressions. For the purpose of description we will make a mould of a engine cylinder head for a full-size prop replica of a Wright Cyclone radial engine. Cylinder head silicone mould The following steps describe the construction of a silicone mould and casting of a prop cylinder head for an aeroplane engine. This replica Wright Cyclone engine