Monday, 22 February 2016

43rd Entry - Final Mould Test

After avoiding the idea of casting silicone from a silicone mould for so many months, all evidence pointed back towards it as the final solution.  In the end it came down to comfort, partly.  I feel relatively comfortable working with silicone, in the comfort of my studio, instead of the highly toxic and extremely fast setting (low work time) urethane, for which the cold darkroom was reconverted as a mould-making workshop.  Silicone makes me happier, and it makes my cat happier, who sleeps in the main part of the room where I would be forced to work the fuming urethane.
The outer rigid part of the mould remains urethane, but the silicone allows for a slow, warm, non-toxic pour. And the newly discovered Platsil Gel 25 offers the options of slowing down work time, and hardening the cured rubber up to shore A 40, which is excellent.  Furthermore, it is much lower in viscosity.

A partial sculpture created for this mould test

yellowed by shellac to seal the clay

The sculpture was held together merely with a soft sticky wax.  When the mould was opened the head stayed with the eye pins, and the body chose the back part of the mould.  Both parts were removed and the clay was cleaned out, meaning that the figure changed position slightly for the next stage.

Shellac was only used in the third part after frustration with the acrylic spray which seemed to never dry.  Everything seemed to take longer to dry than the clay itself.

bleeders and pour spout.

Joseph Feltus' eye mechanism.

Plastic Gel 25 with 50% deadener cast over wire and supersculpey armature.  No overflow, nearly invisible seams on the head, where the mould was most carefully worked for this test.

Nearly invisible seams

Materials used.  Mould was released with hand soap diluted with alcohol before casting.