Zen and the Art of Prop Making

Plaster moulds are the easiest and cheapest of all moulds to make. They are also the heaviest and most fragile. There are two ways of making them. The first is to make a waterproof box around your object, pour in the plaster mix and wait for it to set. The second uses plaster bandage which is normally used to set broken limbs. Steps in making boxed plaster moulds Following is a step by step process in making boxed plaster moulds . They are very straight forward and require no special equipment or chemicals. All that is needed to make plaster moulds is plaster of Paris and some scrap timber to make the box section to hold the plaster mix until it sets. Step 1 Fasten your object to the middle of a smooth, flat piece of wood. Make a waterproof timber dam around it a couple of inches higher than the object. Use plasticene to fill all the undercuts on the object and any gaps between it and the base board. Take extra care doing this because it makes for a better mould. This is very ...

A plaster mould is the easiest and cheapest of all moulds to make. They are also the heaviest and most fragile. There are two basic ways of making them. The method described here is to use plaster bandage which is normally used to set broken limbs. The other method is to pour the plaster into a mould box which is described in another post on Plaster Mould Making . Simplicity of plaster bandage moulds A plaster bandage mould is useful when taking moulds of body parts because it dries quickly and has no harmful solvents. Plaster bandage can also be applied directly to an object without having to make special dams or walls to contain it. To save money it can also be used as a support jacket in lieu of fibreglass when making a latex mould. Step 1 For the purpose of description we will take a plaster cast of a foot. You need to put a release agent onto the skin to prevent the plaster sticking on skin or hairs. Even though it's messy, petroleum jelly is the best to use. Ev...

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...

Fibreglass moulds can be a one piece mould or, if the object has a complicated shape, made in two or more separate pieces bolted together to make the final mould. This makes removal of casts from the fibreglass moulds possible. There have been many unhappy souls who have made a cast in fibreglass moulds only to find they cannot remove them. There is no flexibility in fibreglass moulds so things will get permanently stuck if there are any undercuts. Main points of fibreglass moulds The aim is to make the surface of fibreglass moulds as smooth as possible. If the surface quality of the mould is like a mirror then the cast object will be the same. The extra care taken in making the mould will reap rewards when casting later. Mould release agents or wax should always be applied to moulds before laying fibreglass matting. The following steps are a general guide to making multi-section fibreglass moulds. Step 1 You must carefully plan where you want fibreglass moulds to split. In ...

The first step in making a giant egg is to make a giant egg! From this a mould can be made from which to cast as many eggs are required. Depending on the size of the egg you want to make will dictate how you go about making the egg form. Since the egg we needed to make was about 60cm tall it was decided to carve it from a block of polystyrene. Since the egg shape is symmetrical it is best to turn it on a lathe. The polystyrene has to have plywood boards glued to both ends so a lathe faceplate and tailstock centre can be attached so it can be turned on the lathe. The corners of the block are then cut off at 45 degrees to make turning a bit easier on the polystyrene. If this is not done it is likely large chunks will break off when the lathe chisel is applied to the turning block. It is very, very messy turning polystyrene on a lathe so ensure the work area is covered with something to collect the shavings and clean up regularly as you work. This will minimise the polystyren...