Plaster vs Silicon molds

[efarley]

Hey guys,

I have been watching a show on SyFy channel called Face Off for years which is a show about costume designers where they make some really incredible costumes. Anyways I've noticed on that show they always use plaster for their molds, but now that I'm looking into learning to do this myself I'm finding everyone online and all of the tutorials are using silicone molds. I've done some research but haven't been able to find anything about making plaster molds and what advantages/disadvantages come with plaster. (I've found articles detailing the advantage/disadvantage of various silicons).

Has anyone here worked with a plaster mold, and if so what advantage/disadvantage comes with it? Based on what I'm learning I'll be going with silicon, but I'm curious why these super talented people are all using plaster and never silicon.

 

[Kevin Gossett]

They are probably using plaster as a mother mold to keep the silicone mold structured.

 

[Weekend Warrior]

Different types of molds. On the show they are usually molding a clay sculpture of a face and are not worried about destroying the original in the process. They then use the hard plaster mold to make soft latex or silicone appliances for their models to wear.

The molds I assume you are talking about on this site are soft silicone molds made of a rigid item (like a helmet) that you don't want to destroy and plan on casting in a hard material like plastic.

Basically, in mold making if the end product is to be soft the mold is usually rigid, if the end product is rigid the mold is soft.

This is of course a very basic representation and there are many more factors to consider, just trying to shed a little light

 

[efarley]

Basically, in mold making if the end product is to be soft the mold is usually rigid, if the end product is rigid the mold is soft.

That makes a lot of sense, thanks!