Making Talos Awakes – Part 19 of 20
Ceramic shell investment
Now that the wax tree is assembled, it is ready for coating in the ceramic shell. The tree is dipped into a slurry of silica, then drained off and allowed to dry. The shelling process is then repeated many times with additional grit added to thicken the shell. It takes several days to achieve the required thickness of at least half an inch.
Talos waxes drying after being dipped in silica slurry then dry crystalline silica – three coats
The coated tree is then placed standing on the funnel inside a kiln. During this heat cycle the ceramic shell is hardened and the wax is melted out of the mould. This leaves a negative space within the shell which the wax sculpture formerly occupied.
Bronze casting
After testing the integrity of the mould and reinforcing any areas that may require additional strength, we reheat the shell to bring it up to the correct temperature for casting. This is necessary to prevent the ceramic from breaking due to such a drastic difference in temperature.
Once the bronze in the crucible is up to temperature, the now hot ceramic shell is taken out of the kiln and placed on a bed of sand to support it during the casting. The crucible is then lifted out of the furnace and the molten bronze is poured into the funnel of the mould which is then left to cool.
Shell Removal
The moment of truth, time to remove the shell.
We start to release the metal by breaking off the shell with a hammer, being cautious not to knock any of the exposed castings.
Following this we put the tree into a sand blasting unit to remove the remaining ceramic with a fine grit blast. At this point we can give the sculpture a proper inspection.
Talos Awakes bronzes on trees partially divested of ceramic shell
Feed removal
Subsequently the metal sprues (feeds) will now need removing. Using an angle grinder with a cutting disc we can remove the bulk of the feeds. The remaining stubs can then be sanded or filed down depending on accessibility.
These sculptures were hand made by Raven Armoury in association with The Ray & Diana Harryhausen Foundation.
Based on effects characters created by Ray Harryhausen for a Charles H. Schneer Production.
TM & © Columbia Pictures Industries, Inc. All Rights Reserved.
