Wednesday, 4 May 2011

Jim construction part 1

Hi everyone. When I first got into stop-motion animation there wasn't many books or videos on how to make puppets etc. There are more now but mainly on plastercine. My model will be constructed in silicone. I intend to write full descriptions on how I construct Jim from start to finished puppet.

First I started off by having my drawings of Jim and working out the size I wanted him to be. Big enough to manoeuvre fingers but not too big that my sets would have to be ginormous. Jim is around 20cm tall.

I draw out Jim to 20cm on paper to use as a template for my armature. The armature is made up of metal ball and socket joints. These hold the shape of the puppet and make it possible to move in small increments. From my picture I can work out where the knee, arms and hip joints need to be. So I can cut my armature to the correct size.

This is the armature made to the correct size for Jims body. The armature was supplied by the ProPlus range. It has everything from fingers to toes, once the rods were cut to the correct size everything was threadlocked into place.

This post is going to concentrate on Jims foot.

Here you can see the armature for Jim's foot. I have screwed the foot to the board. This board will be the lid to the top of the cast. It's important to have the foot screwed down so the armature stays in the exact same place for moulding. This will come more apparent later in this blog.

Next thing I did was superglue some upholstery foam to the armature. Making sure not to glue the armature screws. It'll make it hard to unscrew and locate later. The reason for using foam on the foot armature is to help bond the silicone to the plates. Silicone will not stick to anything. It is a very oily substance, very much like our fingers. If you superglued your fingers. The glue would crack over time due to the moisture we give out. Same applies with silicone. So the foam acts as a sponge. The silicone absorbs slightly into the foam and fuses together. This is important at the toe end.

Once I glued the foam to the armature I wrapped it up in cling film. Then I started to make the foot around the armature in plastercine. The cling film stops the plastercine sticking to the foam.

Here is the finished foot sculpted in plastercine around the armature. I have screwed 2 screws into the board to act as locators for later on. There is also a small blob of plastercine by the back of the foot. This is so I have a way of prying the cast apart from the board with the armature/plastercine foot on. I have used foam boards to make a wall around the foot. This is now ready to be cast with plaster.

I am using a resin plaster to make my cast. This is much stringer than your ordinary plaster/stone plaster. I got mine from a craft shop in manchester called Fred Aldous.

The resin plaster takes roughly 20mins to set. I leave mine around an hour. This means the plastercine inside is still a little warm from the chemical reaction the resin plaster has when mixed with water. The screws that were protruding from the board are now stuck into the plaster as locators. next thing to do is unscrew them from the plaster, the board is now free from the plaster. Using the area where the blob of plastercine was at the back of the foot I can pry the board and armature from the cast.

The plastercine around the armature is normally completely ruined but that doesn't matter if the cast has worked like this has. Next is to remove the cling film from around the armature.

Now onto the tricky part. Mixing the silicone. The silicone I use is supplied from

It's a silicone base with a catalyst that's added. For Jim's foot I poured around 30g of the silicone base into a cup. Then I can add coloured oils to this base until I get the desired look. The oils are also supplied with the silicone

The smallest of droplets make a massive difference to the colour. Once I was happy with the colour I left it for 12 hours to let the bubbles come to the service. Then I was able to add the catalyst to the mixture. It's 5% of the base. So 1.5g of catalyst. Doesn't seem a lot but it's enough to make the silicone cure. You really have to fold the catalyst into the mixture so it gets mixed in fully.

The next step is to pour the silicone into the mould. The higher you pour the easier it is to get rid of the bubbles. A thin stringy layer was poured to the lowest part of the mould until it was filled to the top. Then I placed the board with the armature on into the silicone and lined the holes up so I could bang the screws into the board and cast. This squashed everything together and made a tight bond between the silicone and the armature. It was then left for 18 hours to cure. (making sure the cast was placed so the bubbles would surface away from the main detail eg. Bottom of foot, top of arm etc)

Once the silicone had cured for 18 hours I unscrewed the locators and armature screw so I could prise the board away from the silicone. The armature is now inside the silicone nice and flat. Then taking my time I pulled the silicone foot away from the mould. Nice and gently.

I then trimmed the excess silicone from the bottom of the foot and attached the finished shoe to the armature.

There you have it. My first attempt at making a silicone shoe for Jim. It turned out that well I'm going to make the other.

Keep checking back guys. My next post will be making Jim's arms


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  1. wow, very nicely written! I feel that if I ever got up enough nerve to try it, I could!

  2. You should just do it. Make it interesting and informative. Plenty of pictures :-)