Moulds for plaster of paris?

Question

I want to make a sculpture from plaster of paris although I am not sure what material to use as the mould around it so that when it comes to plaster of paris stage I can just pour it in, anyone got any ideas?

Answer 1

You can use either latex, alginate or preferably a two part cold cure rubber available from sculpture suppliers.

Depending on the size and intricacy of your original model (from which you cast) you can make a solid block of alginate and then cut the model from this leaving a hollow for the plaster to be poured.

I prefer the method of coating the model in a thinner coat of silicone rubber before building an outer shell of plaster and scrim (or plaster and fabric) as this will later hold the rubber in perfect position to prevent warping. The only thing to consider with this are seam lines to enable you to take the mouild apart giving you access to the poured plaster model without damaging in in the removing process. This process is also good for producing multiples of the same object.

You can always simply impress an object into plasticine or similar, but it depends on the result you are looking for.

Below i put two good links that will tell you more of this process, the first link is great as it describes and also has pictures ( I learn better with visuals :-) )

Good luck and good fun!