Moulding the figure Part 1

Having finished modelling the figure, it was time for me to start the mould making process. The way that the figure was constructed meant that there was a 'mould lock' around the arms. The mould lock can be dealt with in several ways but I chose to cut away the arms and separate the gun so that I could mould these pieces individually. The head was also removed at this stage.

Above: Image 1 shows the gun with a small piece of plasticine by the barrel, which will help the wax to run to the tip later on. Image 2 shows how I have filled in between the grip and magazine to also allow the wax to flow freely within the mould at a later stage. Image 3 shows how I have established the seam line around the gun with clay. The clay is built up to the half way line with small 'airs' added at the grips, and barrel; when the mould is upside down and filled with wax the air will be able to escape from these points.

Above and below: To establish my seam line for the head and hands I had chosen to use metal 'shim', this is because it is strong and quick, especially due to the fact that the seam lines were pretty straight. The shim is pushed into the plasticine along the seam line and taped together where it overlaps to make it watertight. In image 4 above and image 2 below, you can see where I have added clay keys to ensure that the rubber halves will locate back together later.

Below: In the images below you can see where I have built up walls around the pieces to contain the rubber. Once ready the rubber is weighed out and catalyst is added (a ratio of 100:10 for the particular rubber I was using). The rubber is mixed thoroughly and poured into the moulds. As these are small in scale I had opted to make 'block moulds', this rubber mould has no plaster jacket and relies on the thickness of the rubber to hold it's shape.

Below: After 24hrs the rubber had fully cured. The clay walls were removed from around the moulds, the moulds were flipped over and the shim and clay was removed. The edges of the plasticine were tidied up where the shim had been pushed into the detail, new walls were put up and the rubber recieved a coat of liquid wax which acts as a barrier stop the rubber layers from sticking together. Then another load of rubber was mixed and poured. once that had cured for a further 24hrs the moulds were opened up and the plasticine pieces were removed. The moulds were then given a once over with a sclapel blade to take off any surplus rubber.

Below: finished rubber block moulds of the hands, gun and head ready for the wax stage.