How to make a plaster cast. Hi everyone!! I share with you the process I use to make a plaster cast. In this case I use a skull I already obtained from another plaster cast. In this case I use semi-refractory clay. It is important to make the plaster cast on the still wet model so that it does not shrink significantly. The key part in this process, which can be non-destructive in the sense that if I want I can still not destroy the model I'm using, are the clay walls that delimit the various half-shells I want to make. To them the half shells are consequent to the possible undercuts that I don't want to have. Fewer shells unfortunately usually means more undercuts and therefore you risk ruining the clay model when You extract it from the plaster shell. Another peculiarity, in this case I do not pour liquid plaster, or rather, only at the beginning I use it in a liquid way to make it adhere very well to the surface of the model, after which I start to cast plaster on the model slowly as the plaster begins to stabilize. I use a type of plaster called Alabaster bought at a building depot, nothing too expensive. Don't forget to brush the various parts in contact with dirty water (a very liquid slip) which allows the plaster of the different shells not to stick to each other or to the surface of the table. In this case, in the end, I decide not to keep the clay model and therefore I extract the clay from inside the mold, wash the molds and then lightly smooth the walls of the mold with a rough sponge. Cast ready to make as many skulls as one wants :). Good fun!!