Preparing Plaster Casts

Paige and I had made the decision to use the plaster life casts of 3 of the actors to create fibre glass heads to sculpt on. Although the process is very lengthy, the benefits of using a fibre glass head and therefore a fibre glass mould were substantial. With a fibre glass head and mould the 2 parts can be screwed together and silicone can be injected to ensure an even coverage and almost perfect prosthetic every time. Fibre glass is also a lot more durable and less likely to be damaged than a plaster cast and mould, something that would be essential for a project that would run over a period of months and require multiple prosthetics to be made from the same mould.
We divided our time and focus so that Paige would concentrate on creating the head and subsequent prosthetics for Josh Lonsdale, I would focus on John McDonald as the Hunter Orc and we would share the responsibility for the creation of moulds and prosthetics for Josh Whorriskey. This would eventually result in us having 3 high quality, full-head silicone pieces that could be featured more heavily on camera.

The first stage in the process of creating fibre glass heads was to clean up and perfect the life casts. This was initially quite a simple task of sanding down any rough edges and scraping away the build up of plaster in places like the eyebrows and eyelashes. The problem came, however, when we applied small amounts of plaster into areas that had had air bubbles. Although we used plaster marked the same as the plaster we had used to fill the life casts, the plaster appeared much darker on the surface of the cast and became very difficult to smooth out and sand away. Eventually we were forced to chisel off any areas of the plaster we had newly applied that would not sand away. This added a significant amount of time onto the clean up process.

Once we were happy that the life casts had no lumps, air bubbles or rough surfaces, we could begin to prepare them for the process of creating fibre glass copies. The first thing that needed to be done was to secure the casts onto a wooden board to ensure that they are on a level surface and will not move during the fibre glassing process. We used clay to build a base to sit the casts upon, raising them up off the surface of the MDF board slightly and ensuring that they were level.

Once the casts were secured they needed to be coated in 3-4 layers of shellac plaster sealant as plaster is a very porous material, this turned the casts a dark yellow colour.