Sculpting issues and Moldmaking

Further Sculpting and re-sculpting has taken a bit longer than I would have liked but has been a learning curve. I knew from the outset that this would be the most difficult part of the project for me as sculpting really doesn’t come naturally. The hard part comes in deciding to 'destroy' parts that appear quite correct but need complete overhaul to really perfect them.

Of particular difficulty were the facial details, especially the mouth. As the photos above show, the mouth changed radically before the point of molding. I must have spent the best part of 2 days working on getting it right. The final mouth may still not be perfect but I felt the overall look (see below) of the sculpt was correct and further modification would have increased my frustration with it and likely affected the quality.

With the sculpt complete I began making the mold. Initially I had discussed making a fiberglass mold that would not require a silicon jacket. However, discussing the subject with Julia in the workshop, we decided it was best if the front was covered in silicon to ensure the slight undercuts and facial detail were preserved in the mold. In order to do this I created a clay wall around the outside of the sculpt and over the head (see below). The cut outs allow silicon to 'key' into the fiberglass jacket at the next stage.

Mixing up the silicon with Thixotropic and Accelerator I was able to apply a good coat to the front of the sculpt (above). Normally this process would be carried out with a layer of silicon (no additives) to ensure that air bubbles escape from the mix. I skipped this layer due to the lack of detail on the sculpt and my easily being able to see which areas were sufficiently covered before applying more silicon. 

I began the fiber glassing process by applying a layer of gel coat across the silicon and over the clay walls (above). This creates a solid layer that will secure the silicon in place during casting. Once tacky (after around 20mins) I began to lay up with fiber glass starting with the thin weave and building up to the thicker (below). All fiber glass was applied using standard polyester lay-up resin.

  

Once each layer of fiberglass has cured with the resin I added another (approx 3 times) to create a good wall thickness which will be necessary when prising oven the mold (applied fiber glass seen above).

 The back section of the mold presented problems due to its unusual shape. To make it easier to de-mold I split it into two with a wall down the middle (above). Before applying gel-coat I ensured that the exposed fiberglass on the front of the mold was well coated in beeswax and Macwax to act as a barrier between the two.