To start off this new section of the website I'm posting some pictures of the work involved in making the mould for "Quantum Tunneling", a limited edition
cold-cast bronze sculpture.
Because the figure is quite small I decided to make a so-called "block-mould" for each of the limbs and the head. Block-moulds are made entirely of silicon,
and for any given size require more silicon than other types of mould. However, for a sculpture on this scale, the amount of material remains within reasonable limits. Each of the
block-moulds is made of two halves; this allows it to be taken apart so the cast can be removed.
Now using a thin flexible plastic, a containment wall is made around each piece. (The purpose of the nuts will be apparent in a minute) Now silicon can be
poured into this "container", forming the first half of the mold (see below).
In goes the silicon!
Below:Air bubbles rising to the surface, silicon is usually quite thick
so I used silicon thinner with this mixture to make "degassing" easier. I would otherwise use a vacuum chamber to suck the air out before pouring.
The mould has been turned over, and the water based clay partition has been cleaned away. The point of the nuts can now be more easily understood, when the
second half of the mould is poured, the silicon will flow into these holes and match the shape perfectly. This will allow the two halves of the mould to sit perfectly together each time it is
used. The nuts act as a so called "key".
The containment wall is built again ready for pouring the second half. The arms in the picture below have caught the camera flash quite strongly. This is the
release agent that was brushed onto all surfaces giving it a shinny look, this helps the silicon "release" from surfaces making de-moulding possible. Although release agent is not really
necessary on the sculpture itself, it is absolutely critical on the already cured silicon surface. Silicon bonds to silicon and the mould would otherwise not come apart!
In goes the silicon for the second half. Again it's left overnight to cure before de-moulding.
The first step is to create a partition wall around the sculpture at the point where the two halves of the mould will meet. Below are some pictures of the
limbs with the dividing (partition) wall already in place. The original figure is made of oil-based clay so I made the partition wall using soft water based clay.
The making of Quantum tunneling
Extras -Quantum Tunneling
The big moment! (Now is when you find out if you forgot your release agent or not).