Allow me to introduce you to the glorious world of Silicone. The material we used to surround the wire armatures and give our puppets body. So where do I start? Shore strength? Viscosity? Cure time? Ratios? If you’re a beginner like I was before dealing with this stuff, it can all seem a little overwhelming.

I started my education in Barnes where the assistant guided me through the various types of Silicone. They ranged from flesh-like consistency for prosthetics, to hard rubbers. Fortunately they had samples of each one that allowed me to pick them up and bend them back and forth. I was looking for something that would allow me to bend the underlying armature in our puppets into a position and not have a tense silicone slowly move it back into place. I chose a product called Soft Translucent Silicone which was quite bendy yet still rigid enough for me to handle on not squish between my fingers. Here’s some technical product info:

Soft Translucent Silicone is a high strength, two component, tin catalysed, translucent RTV silicone rubber. It can be intrinsically pigmented which makes it ideal for the SFX industry. This silicone has a very low viscosity combined with a long pot life and accurate detail reproduction. When diluted with up to 30% silicone diluent, it will produce a floppy “skin like” feel.

Typical Product Use

• Skins for robotic and animatronic figures displayed in permanent or travelling expositions SFX skins and props for the film industry
• Theme park props and reproduction molds
• Very flexible general purpose molds

The tricky thing about dealing with Silicone is that it comes in two parts and must be mixed in a very specific ratio. The shop assistance put the fear of God in me by warning that if I get it only a few mills wrong, the silicone wouldn’t set. I ran out and got a decent kitchen scale that would allow me to accurately measure the proportions. After working with the product for a while I realised she was being a little over dramatic.

The other ingredient we used was a silicone diluent. This effectively makes the silicone softer and we used a ratio of 10% in our mixture.

Now, down to the nitty-gritty. With the wire armature securely in place, we painted each face of the open mold with Vaseline before we closed the two sides together. This would ensure that after the silicone set, the two sides would easily come apart. If we forgot to do this step, it was often very difficult separating the mold, sometimes breaking them in half! This happened for our mold of Zero. I had to Araldite the broken mold back together which thankfully saved the day.

We often ran clay around the perimeter of the molds to ensure silicone didn’t seep out the edges.

With the silicone all mixed up, we simply poured it into the pour hole we made earlier in the mold. It really helps to have a funnel because the silicone is quite thick in its final consistency and will spill out over the sides if you try and pour too fast.

Once set, I carefully pried each side apart with a screw driver or butter knife (depending on the strength and shape of the mold).

And simply plucked out the finished cast.

Because we would later wrap our casts in wool, we wanted to ensure the silicone was the same colour as the wool. This was to ensure that if a character was posed into a position that revealed the silicone between the strands of wool, you wouldn’t be able to notice it.

To do this, we added a pigment to our mixture designed specifically for silicone. The Zero character only required a white base, but the other characters required a pink base to match their wool. Christine always managed to mix together the perfect consistency of red and white.

Now that the sculptures had been cast, it was time to move into fabrication. Stay tuned for our next post and feel free to ask any questions about the above process in the comments.

• Zero Gallery: Disasters, Fun & Peculiarities
• Turning Heads
• Fabrication: String, Hair & Accessories
• Behind the Scenes Video
• Building Wire Armatures