Epoxy Mould Making
Moulds usually consist of 2 parts, 1/ The mould face: The face needs to be hard and scratch resistant and should be buffed to a nice shine. 2/ The mould backing: The mould face is normally only around 2mm thick, so the backing needs to support the face, giving it enough strength and stiffness to hold it dimensionally stable throughout its working life.
The advantage of using epoxy molds are there extremely small shrinkage, this ensures an accurate part.
A tooling gelcoat is standard to use as the mould face, however the backing can vary between chopped strand mat, or a laminating paste or a combination of both. If you are using chopped strand mat as a backing, it can be good practice to use a paste to fill in any tight concave curves that the chopped strand may bridge over.