Before work could continue on the lid, I needed to make several props. Namely, skulls. This pair of happy smiling faces would form the masters from which more skulls would be cast. These two are made from resin and are leftovers from a previous project some years ago. (I never throw anything away!)
First, a latex rubber mould was made of each skull.
The latex mould is built up in layers. The first couple of layers are applied ‘un-thickened’. The latex is quite runny straight from the tin and generally requires a thickening agent for it to ‘bulk up’. Applying the first layers un-thickened allows the solution to run into any nooks and crannies and hence capture any fine details.
Once the latex had fully cured, the moulds were peeled off the resin skulls then washed and dried. The new skulls were cast in plaster of paris. The skulls were cast in pairs and left for 24 hours to harden before being removed from their moulds. This whole process took five days since I made ten skulls, five of each design, although I ended up using only six of them.
As with any simple casting, there are nearly always some imperfections that need correcting. The skulls were thus tidied up with a modelling knife and small files. One advantage of using plaster of paris is that it is very soft and easy to cut/grind, an advantage that is put to use in the next step.
Since the final effect I was after was of the skulls being half buried I needed to flatten one side. This was easily and quickly achieved by rubbing the skulls on a piece of medium grit sandpaper.