To begin moulding the figure I had to first cut off the left arm. This was because I couldn't mould the figure with the arm attached. The reason I couldn't mould the figure in its current state, was because I decided to make a silicone mould and it was impossible because of the undercuts to mould the figure with the arm attached. We cut the arm off by using a wire to cut the clay cleanly and then used a hacksaw to cut thought the aluminium wire. We marked the arm with two marks so that the arm can be attached correctly when they are eventually cast.
|
The next stage of the process is to divide the sculpt so that I can create two halves of the mould. This is important again exactly like the left arm, so that I can avoid undercuts. The sculpt needed to be split into two separate halves. This was created by using shim, a thin metal sheet that can be cut down and stuck directly into the clay. The tidier the shim is inserted the better the seams turn out in the final cast. Shim was inserted all around the sculpt, and by using key shim (plastic shaped to have divests in) could then be used to key in the silicone mould to locate itself to return to its original shape.
|
Once the thixo layer was applied to the back, I then began attaching keys. These knobbly additions are simply to help the mould fit back together again. they are made from the same silicone as the mould using templates. The thin linear keys are used later to divide the mould into different parts so that the mould can be split and taken apart easily.
|
Once all the thixo layer of the silicone was complete, and the keys were added I could then begin to add the last shim to the mould. This shim was added to the thin tubes of keys so that the resin mould pieces could be separated making it easier for the mould to come apart. The shim was inserted by using a thin blade to cut through the key to the clay underneath and inserting the shim into the cut.
|
In addition to the main body, the arm that I removed earlier in the process needed to be cast. I did this by first securing it to a metal rod attached to a board so that the arm could be stood upright. The arm was then covered in a layer of silicone, (the colour being more purple because I added a faster setting catalyst to the mix). Shim was added to the sides of the arms, and a second layer of thixo was added.
|