After finishing the sculpt as you can see in the time lapse above, I put each half of the sculpt on buckets and used a copper wire to push through the sculpt at the low points and details of the skin folds, mouth edges and eye corners. Because I had planned this, the holes drilled in the MDF guide made it relatively easy to locate the parts of the sculpt that had no MDF underneath them, so the wire could be pushed in at an angle and pulled all the way through and out of the other side. These holes allow the vacuum former to suck the details in whilst the plastic is hot, and prevents any air bubbles and loss of detail.
Vacuum forming is always a little nerve wracking on a soft clay sculpt, as it's often only the one chance you'll get before the sculpt is heavily damaged. I was very lucky in that both sides of the sculpt pulled perfectly first time in the vacuum former.
|Shiny, smooth and detailed!|
As you can see, an unfortunate side effect of using the plastic baubles as the eyes in the sculpt was that they got absolutely stuck to the inside of the vacuum formed face, causing more destruction to the original sculpt in removing the face from the sculpt. Whilst this is not a huge issue because they don't add any considerable weight, I wanted to make a plaster cast of the inside of the heads before I began cutting them up, just in case I made a mistake or needed to modify a part of the shape.
To fix the problem, I used a Dremel with a cutting wheel and a sanding end to remove the excess bauble until it sat flush against the eye socket. After doing this I began filling the inside of the face with a fine casting plaster, propping it up with styrene blocks I cut on the bandsaw to be the same height as the highest point of the face, double checked with a level.