Hyde Park Mouldings, Moulding a Pilaster
For this project we would be moulding a pilaster for replication in a building. Once the initial pilaster is constructed in the shop plastic is lined over it to protect the surface. The first step is to construct the outer fiberglass shell, and only after that is complete, is rubber pored into the shell to make a mould of the details of the pilaster.
This would be my first experiance working with fiberglass and rubber. The ratios and weights af catylists to rubber must be very exact to make a proper mixture, everything is weighed on a scale, even the debris from the first inner shell before the final rubber pour is started.
The pilaster before finishing, all the screw holes are then filled with plaster and touched up
Plastic is laid down and an inner shell is constructed. This sell would later be disposed of and is only used to support the outer shell and protect then inner pilaster from spillage.
Clay is then built up around the details of the pilaster
Once everything is sealed all surfaces are shellacked so the fiberglass will not adhere to the surface. Two or more thorough coats of shellac may be needed.
An epoxy is then painted on and fiberglass strands are painted into the surface. This creates a mesh work that reinforces the surface. Metal rails are then attached and intigrated into the mesh to give the shell strength.
Plywood is then cut to connect the metal rails for cross support. When it is dried it is pried loose with a crowbar. Once the outer shell is removed the inner shell is discarded leaving a hollow area inside the shell between the pilaster. This area will be filled with rubber.
Holes are drilled in the surface of the shell in multiple places to allow air to escape, and large holes are cut for the pouring in of rubber. The air vents are sealed with clay to prevent leaking.
The shell removed. The pegs that can be seen protruding from the mould are where the air vents were. all these rubber pegs are cut off giving a smooth surface.
Here can be seen how the rubber mould adheres to the plaster pilaster forming an exact fit. To the right is the outer fiberglass shell.
The mould placed in the shell, ready for use in casting.
Finished cast of the Pilaster
