Man of the Future: Step 8
Hello again and thank you for joining me for this Artist’s Studio. We are now at the foundry and readying the piece for mold making. As a quick preface, I will summarize the casting process for you:
- first a rubber and plaster mold is made on the clay sculpture
- the clay is removed, and hollow wax castings are made from the mold
- the wax castings are encased (or encrusted) with ceramic
- the wax is melted out, and molten bronze is poured into the hot ceramic mold or “shell”
- the bronze pieces are chipped out of the ceramic and welded together, ground, polished etc.(”chasing”)
- last,but certainly not least, the bronze sculpture is given a “patina”- a chemical treatment to color and finish the bronze
The clay sculpture must first be prepped for the rubber part of the mold which will be painted on in layers. The fin encircling his torso is called a “shim”, it’s a piece of thin metal which will create a separation in the mold to make pieces which are small enough to handle easily. The round shape on the back creates a “lock” so that the cast pieces will go back together where they are supposed to.
The finished mold will now have two separate parts, which in turn will each be split again like a clamshell. (keep watching and all this will start to make sense) Note the large white piece in the background which has 3 shims to make 4 smaller molds out of it.
The blue is the rubber mold material. It is a catalyzed compound that comes in 2 liquid parts — when they are mixed, the two react and set up into rubber after a given amount of time. Successive layers will be painted on, later layers being thickened to a frosting like consistency to speed up the process after the surface detail has been captured.
Again, note some of the other pieces in the background that are in later stages. If you look closely on the right in the first photo, you can see that the book has already received several coats.
