Zero

With the prototypes set in stone, or rather, clay… we had to make molds of each character which would allow us to produce multiple casts of each body shape. We learnt a lot during this process and evolved our technique over time.

To get started, we built a basic bed of clay around the model so it was submerged half way. A cylinder was placed on the characters neck which breached the edge of the base. This would serve as the hole that would later allow us to pour  silicon through.

Using the end of a marker, we pushed 4 holes into the clay which acted as ‘keys. This would eventually allow the two sides of the finished mold to lock together so they couldn’t rotate. Wires were also placed protruding out from each limb which would create channels for us to place our armature wire into (more on this in a future post).

Four walls of clay were built around the base creating a basic box. We smoothed it down onto the table so the whole thing stayed firmly in place and the plaster we were about to pour couldn’t escape out the bottom.

The model and clay were then painted in Vaseline. This would act as a release agent that would ensure the plaster would easily pull free once dry. You can purchase release agents in spray form, but Vaseline (or petroleum jelly) is cheap and does just as good a job.

Plaster of Paris was then mixed up, ready to pour. I’d advise you you ignore the ratio instructions on the packet as this makes your consistency too runny which results in slower drying times and a weaker mold. Simply add your water to a container and start pouring in your plaster bit-by-bit, stirring it through. Your goal is to create a consistency similar to that of soft serve ice cream.

As the plaster is drying, you’ll feel it warm up. You’ll know you’re ready to move on when it becomes cool to touch, at this point peel away the clay and the first half of the mold is complete.

Repeat your earlier step by rebuilding walls around the mold in order to pour the second half. Don’t forget to add your release agent… then pour away.

The photo below shows two halves of a finished mold, the model itself, didn’t fair so well. This isn’t the same mould as seen above and serves as a good example of what happens to your model if you don’t apply a release agent!

Earlier in the post I mentioned our technique improved over time. Besides gaining a better understanding of the right ratio for mixing the plaster, a big time saver came in the use of using found containers as the base for our molds. In the photos below, I used an ice cream container and a cardboard box. The cardboard box was a bit radical but at the time, I didn’t have anything big enough on hand to fit my model. I’d recommend sticking to plastic containers.

The use of found containers literally saved us hours of time, but the process was slightly different. Instead of building up a bed of clay around the character, we filled up the container half way with the plaster, then submerged the model half way. It won’t sink to the bottom if your consistency is thick enough (like soft serve ice cream as mentioned earlier).

When it dries, simply apply your release agent and pour in the second half. Quick and easy! Feel free to ask questions about this process in the comments below.

If you enjoyed this post, why not subscribe to my RSS feed?

Previous posts from 'Behind the Scenes':

• Fabrication: String, Hair & Accessories
• Behind the Scenes Video
• Casting Your Puppets
• Building Wire Armatures
• Sculpting Prototypes