Monday, 17 February 2014

Casting Feet

Still behind, its going to be a busy week of blog posts. On to the feet! these are much easier to post about than the hands. Initially the feet were sculpted onto the ball and socket armature. The joints for which were wrapped in PTFE tape in order to protect them through the entire process. 

I've made sure that the ball from the top of the leg is NOT attached at this point in the process. This is so that I can pour plaster on them up to the K&S and still be able to get the armature out afterwards. 

Above are the feet for Roy, with much shorter shin pieces but still with the ball missing from the top. The process for the shoes was the same for each pair. The plasticine was then sculpted to the foam board base to ensure no plaster went underneath. 

I made the mistake of not putting vaseline on the base of the foam board. This didn't make the cast stick to the base, but did (as you can see below) take the top layer of foam board off and make the cast look a little messy. 

Once the walls were glued in place, making sure not to leave any gaps that plaster could come through, A layer of plaster was first painted onto the shoes in order to capture all of the detail, before more plaster being poured in a constant thin stream until it had reached the correct level. I then agitated the cast for 5 minutes to allow for any air bubbles in the cast to rise to the top of the mould and not affect the sculpts. 

Once the plaster had set, I took out as much plasticine as possible then cleaned the rest out using a paint brush and lighter fluid. 

I then reapplied the PTFE tape where it had been slightly damaged and put the armatures back into the moulds so that when silicone was poured in, the armature fit perfectly. 

As the feet slightly pushed out of the top of the mould, when the mould was flipped to be filled with silicone, the armature would hit the table without the plaster doing the same. In order to balance this, I applied a layer of plasticine to the same level and completely plugged the area when the armature sat so that no silicone could come through. 

Initially, I painted in one layer of silicone so that if there were any air bubbles when more is poured in, they wouldn't be at the surface. I then made sure to screw tie downs into the armature so that I could accurately locate them once it was fully submerged. 

The armatures popped straight out of the moulds with a little persuasion peeling the silicone slightly away from the edges. 

Then it was only the seam line to trim...

and the base to trim around the tie down point. 

I then attached the ball on to the armature ready to be put onto the full armature. 

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