TUTORIAL - basic two part mould

Just a quick, and hopefully easy to understand, tutorial on how to make a basic two-part plaster mould.

First you start with a positive. This is the part you sculpt on. Could either be a cast of your face, chest, arms.. pretty much anything.

!! With a mould type like this there is one very important thing to keep in mind, undercuts. The positive needs to go either straight down or out, if not the negative you make over it will lock on. Making the mould very difficult to impossible to take apart !! 

So now you have a finished sculpted piece and start preparing for the next step, adding a flashedge. This is added to make leftover casting material to "escape" and will make the edges on your finished product thinner.
"Keyholes" are also cut out in the flashedge to stabilize to to parts and make a snug fit.
Second picture is of a different project, but the method is the same.


I sadly have no picture of the plaster application. (very hard and messy to take pictures while your hands are covered in plaster). First you add a thing layer of vaseline where the wet plaster meet the dry plaster. Or else it might get stuck together.
But just like with the lifecast, this goes for the positive aswell, start off with a spashcoat to get all the details.  The go inn with layers of fiberglass "fabric" together with the plasters in two layers. After that you add plaster till you get a thickness of about 1 inch (2,5cm). At the end you just add a but of plaster to make a nice, smooth and pretty mould :)
Between each layer you should also wait till the plaster is semi dried (when it looks more dull and not glossy) before adding the next.

Wait till it dries. I like to wait over night. And carefully open the mould, clean it and it should look something like this! :)

So, not you can cast several copies! You can either cast in gelantine, foam latex, silicone...

Keep in mind to to use latex and silicone in separate moulds as the two materials are not very friendly and it will ruin your mould.

This is a foam latex casting shown above.
I hope this inspires or motivates you to try something like this yourself. ANd as always, got any questions, just ask!
- Karin Olava

Feel the Space Magic!