Chances are that you will need more than one clay figure, in fact you'll probably need a small army.
Here's an inexpensive way to make 'clones' of your original sculpture.
Armature wire (1/16")
Van Aken Plastalina Clay
InstaMold Mold Making Compound
Baby Oil (Mineral Oil)
Double Boiler (or cooking pot and glass mixing bowl)
Paint and brushes
Imagination, patience and a video camera (optional)
Step 1: Draw your character!
For a full sized character aim to draw it about 9-14" in size.
In this tutorial Gromit (being a dog) was fairly short at about 9".
Make the drawing fairly simple, something that will be possible to sculpt in clay, and for which you can envisage a simple wire armature (skeleton).
Step 2: Give 'em some bones!
You will end up with 5 pieces of wire (2 arms, 2 legs, a torso), Assuming you are making a humanoid.
Each piece of wire will be double the length of the body part it represents. For the head leave a big loop in the torso wire, and put loops for the hands and feet.
After you have cut the wire to the right lengths and use the drill and pliers to twist them together.
Use the Sculpey to block out the chest, pelvis, hands and feet of the skeleton, and to hold the wire together. When you are done put the armature on a baking sheet and bake the Sculpey permanently hard in your home oven, 15-20 minutes at 275ÃÂºF. Remove and leave to cool.
Step 3: Sculpt your clay figure.
I won't talk you through this, but their are plenty of sites with good tips on sculpting clay:
If you already have a figure you wish to copy skip to the next step.
Step 4: Make a box
In the case of Gromit the dimensions were 8" deep, 12" long and 8" wide.
When, you have made your box, make sure the seams are water tight (use packaging tape to line all the corners) and then line the bottom with about 1 1/2" deep of squished 'pellets' of clay.
Step 5: Bury your Buddy.
Use the petroleum jelly to lightly coat the back of your figure.
(Your original figure is likely to need cleaning and touching up after the mold creation process, petroleum jelly makes this an easier task as it acts as a lubricant/mold release).
Lay your clay figure backwards onto the base of clay pellets.
Gradually build up the clay pellets around your figure until it is half submered by them.
When the clay pellets are burying your figure to half it's depth start to apply thin smooth sheets of clay onto the pellets.
Push the smooth clay up to the very edges of your figure making sure they form a tight seal around it. Make sure there are no holes that mold compound can run down.
Now push four 1/2" ball-barings half-way into the clay (one in each of the four corners of the clay) and leave them there. This creates 'keys' in the mold which allow it to fit back together again once the clay original is removed. (You can use anything to make a key, I typically make protruding clay ramps on the clay surface as keys).
Step 6: Encased in algenate!
InstaMold is very simple to use, it is a white powder that when mixed with water forms a jelly like substance (algenate). Follow the instructions on the side of the canister as to how much you will need to cover the area of the box. You will need the algenate to be 1 1/2" deep to get a (fairly) strong mold.
You can use any number of different molding compounds for this step, algenate is by far the cheapest.
The best quality molds are made from silicone rubbers, although not all of them are suitable for use with clay originals.
Algenate molds are fairly fragile and short lived, you will probably get 4-6 castings from an algenate mold if you are careful.
Step 7: Flip side up.
Carefully remove the clay pellets from the underside of the mold and your figure.
Build new box sides around your mold, reaching 1 1/2" above the back of your figure. Make sure the edges are water tight.
Line the edges of the box with clay to create a tight seal with the mold and the box.
Coat the mold, and the back of the figure, with mold release or a thin coat of petroleum jelly. This will stop the second half of the mold sticking to the figure and the other half of the mold.
Roll up paper tubes and push them into your figure where you want your pouring holes (for the liquid clay later in the casting process) to be.
For Gromit I used 4 different holes to ensure that hands face and body all filled evenly and fully.
Mix up some more InstaMold and pour it over the figure (avoid displacing the paper cones).
Step 8: Impressionable.
Clean and residual clay and petroleum jelly off your mold using paper towel/tissue.
Step 9: Wirey little fellows aren't they?
Place the finished armature in the mold (making sure the feet face the right way).
Put tiny blobs of clay under the armature to raise it off the bottom of the mold, so that it is not touching. (Use clay that is the same color as the figures skin).
Spray both halfs of the mold with mold release and place the half with holes on top of the other half, making sure the keys lock into place snugly.
Use an elastic band to hold the mold securely together.
Step 10: It's getting hot in here..
Place the glass mixing bowl onto the pan and turn the heat down to a light boil.
Put the Van Aken clay into the glass bowl and allow it to heat up until it is liquid and runny (stir regularly).
Make sure it is fully liquid before trying to pour it into the molds' holes.
Do the pour quickly, clay cools fast and you don't want an incomplete mold pour.
Oddly enough, the clay color used for Gromit doesn't melt as well as other colors, so you may need to add a tiny bit of mineral oil to the clay while it is melting to make it more liquid.
Be careful though, the more oil you add the softer the clay will become. Make it too soft and you won't be able to animate it later.
You can use a double boiler instead of the pan/bowl arrangement, but the results are the same.
Do not try and melt the clay in a fry pan or on direct heat, burnt clay is toxic and useless for animating.
Step 11: They're alive!
I use small drilled beads as eyeballs. I paint them white, then I paint a wide black circle in and around the drilled center hole. I then paint the eye color on top, leaving a thin black line around the iris.
For the other accessories I use Sculpey and then paint them.
When the clay is fully hardened in the mold (15-20 mins), take off the rubber bands and open the mold slowly and carefully, trying not to tear the mold or damage the clay.
Remove your clone. Attach to a base for cleaning and finishing.
Make another (Step 9 onwards).
Take over the world.
Step 12: Movie Magic & Resources
Computer Stop Motion Software
Stop Motion Pro: (Recommended)
Cost: $70 - $595 (depending on edition)
Cost: $99 - $639
Cost: $200- $1500
StopIt: (Basic, Not recommended)
TrickFilmCam (Basic Not Recommended)
Cost: $49 - 499
Stop Motion: Craft Skills for Model Animation: $25.71
The Art of Stop-Motion Animation: $29.99
The Animator's Survival Kit: A Manual of Methods, Principles, and Formulas for Classical, Computer, Games, Stop Motion, and Internet Animators: $19.80
Timing For Animation: $27.95
Cracking Animation: $32.24
Armature wire (1/16"), eyeballs, instructional DVD's & plastic stick figures.
Clay, Sculpy, molding materials, and general art supplies.
Armature Wire, Clay.
Many art stores also carry the materials needed. Armature wire is 1/16" aluminum wire. The clay is Van Aken Plastalina.
Online forums / resources: