Get an appropriate sized board for your character/sculpture you've created. Then add a thin layer of clay onto the board, so that the sculptures weight can be distributed evenly. Because the next step may create some pressure onto the sculpt, possibly flattening the sculpt in various places. Which would not be good after all that time and effort you put into creating your finished sculpt.
Place your character onto the board, and begin to build up the clay half way around the entire sculpt. Take greater care around the hands when doing this step, because you need to make sure the clay is all around the fingers with no gaps. Because when poring the plaster mix it will go underneath your sculpt possibly ruining your mould.
TIP: An easy way to do this is to measure and ink a half way line all around your sculpture as a guideline.
For casting the feet (especially if your armature has metal plated feet) it is important to build up the feet with clay, as the mould will recreate this aspect. And the armature plates can then be aliened correctly onto the mould ready for adding the foam latex.
Once the clay is completely covering half of the sculpture, as show in the left image. You need to go round the entire sculpt with a sculpting tool, too smooth the edge of the clay. Ensuring there are no gaps between the sculpt and the clay. As shown of the right image.
Now the clay base is constructed around the sculpt and completely water tight. It’s time to construct a box around the sculpt, as shown on the first image (left). To make the box more stable, tie string around the wooden blocks and applying large amounts of clay at the seams of the box. To make the box water tight, ready for the plaster that will be added.
The box is now ready for the next step, add clay inside the box all around the seams to again make water tight (as shown in the right image ). Once done gently create little circular indents with your thumb. This will create slots for your mould, helping to align the two parts of the mould. I also add blocks of clay, these areas will create an where you can prise apart the two halves of the mould.
Now the sculpt and box are completed and water tight, it is now time to add the plaster to create the first half of the mould. Before this though, a soap solution is covered over the entire area to help separate the two parts of the mould.
Mixing the plaster: First I placed 10 pints of water into a bucket, and then added 15lb of plaster. Now mix the solution until smooth, approximately 4 minutes. Once smooth keep testing the thickness of the solution by removing your hand to see if the solution is white and looks like a sleeve. When thickened slowly and gently add the solution to the box. Once poured gently rock the table or box, to remove any air bubbles off your sculpt. The left image indicates I didn’t have enough plaster, as you can quite clearly see the belly and nose. A common problem with large and bulky sculptures. So I made another mixture of plaster only 6 pints of water this time, again rocking slightly to remove bubbles. The first piece of the mould you’ve just made should look something like the image on the right.
TIP: Make sure there is a substantial amount of plaster on top of the entire sculpt, if not this will create a weak layer of plaster which may snap or break in the final stages of this process.
Leave the plaster to dry for several hours, until cool and dry.
Once dried, remove the box around the mould and flip over being gentle not to crack or smash the plaster. Now removing the clay from the plaster and the sculpture, hopefully the soap mixture you applied will help this step. Once removed, scrape carefully any excess clay off your sculpt.
TIP: To remove the majority of the clay I usually get a paint brush and water, wiping around the seams and smoothing down the entire sculpt from clay.
The sculpt is now clean from most of the clay, it is time to create the second half of the mould. Again boxing up around the plaster cast so far and making it water tight again by adding clay around the seams (like in Step 5). DO NOT forget to apply the soap solution before adding the plaster solution.
Now the second part of the cast is dry, it is time to pull apart the separate parts. If you have created the large clay points in Step 5, separating the halves will be easier. I placed a chisel between the two moulds and gently part them. You will then be left with two separate halves of your mould with the sculpture inside, like the image above.
Now remove all of the plasticine from the mould that your sculpture may have left, to give you clean looking moulds, like mine above.
TIP: Do not worry if pieces of your mould fall off or apart, if they are large pieces simply glue the pieces back on with some super glue/ two part glue. If an important small part falls off like the eye socket, get some Millieput and simply re-sculpt it back onto the mould.
Unfortunately not everything can make it through the moulding process, like my sculpt of Domovoi here. I had to scrape his head out of the mould. The mould you produce will look exactly like your sculpture with any luck.
Now the mould is complete, it is time to check that your armature correctly fits into your mould. Or if you haven’t got an armature already, this is a perfect time to create one ready for the next part of the puppet making process.
The last step is to place all your mould into a dryer or dry area, and leave for a couple of days. To make sure all the moisture is removed ready for Part 2 (Adding the foam rubber to your moulds)
WARNING: If you do NOT leave the moulds to dry this may break or even destroy the oven in Part 2, so Step 13 is VERY important!!!!
Hopefully I have explained each step well enough for everyone to be able to create their own moulds. Any questions please ask away :)
And stay tuned for ....
PART 2 : Foam rubber