As the face cast is kind of on hold at the moment as I having trouble re-modelling the wax cast into the right shape (by heating and manipulating when pliable). My initial plan was to make a better plaster mould from the repaired wax cast. Then a silicone cast would be made, which I was going to fit over a rigid support. I had this skull shape that I had been working on ages ago, which I could hopefully re-model into a decent support. I bought some expanding foam to fill in the holes in it, and to make a lower jaw. With a separate lower jaw it could be animated to sync to some dialogue.

 

 

To make a lower jaw section with expanding foam I needed a mould - for the basic rectangular shape. I also needed an armature that could be connected to the skull, so I bent some wire into roughly the shape of the curve I wanted. I decided to use a plastic container for the mould (Chinese take-away). The expanding foam is easy to cut and shape, so the mould just had to be slightly bigger than the shape I wanted. I glued some wooded skewers (kebab) across the top of the container to support the wire armature - keeping it away from the sides and bottom so it would be hidden by the foam.

 

It took a few goes to get the wire into the right place, as I was securing it with masking tape, but its all ready now - just to add the foam.

 

As there is no silicone available in the materials store at the moment I decided to work on a hand cast. I figured that this could be animated - with an armature fitted - a bit like the hand in 'The Adams Family' film. Again I will make a plaster mould (of my own hand) and, as there's no silicone, I will use some industrial silicone sealant that I bought recently but never used.

 

 

I started off by making a mould using my own hand. After finding a suitable container (sweets) I cut a groove in the side to allow my hand to sit flat - near the bottom but with a space for plaster underneath. It was big enough to do both halves of the full mould i.e. make the bottom half, let it set, and then fill the top half. I forgot to put any release agent on the container before I mixed the first batch of plaster, so I put a plastic bag around the edge before pouring in the plaster to prevent the plaster sticking to the container.

 



 A close-up of the bottom half of the mould shows up a few imperfections. This was due to me forgetting the release agent and wasting time finding and fitting the plastic bag, before pouring the plaster. This delay meant that the plaster was already beginning to set as I poured it in, which meant it didn't spread properly. Still, I should be able to fill these small holes with plasticine before casting.

Once the bottom half of the mould was set I spread some release agent (vasaline gel) over the top of it to stop the top half from sticking to it. I also had to apply masking tape over the plastic bag that was lining the inside, as it also needed a layer of release agent, but it kept moving - so the tape kept it in position.

 

 

 

You can see from the image above where a section was cut out of the side to allow the hand to sit low in the mould, but also at a fairly straight angle.

 

So once I had the second batch of plaster mixed I replaced my hand in the bottom section and poured in the plaster. I made the second mix a bit runnier so it would find its way into any gaps. This meant it would take longer to set. As you can see I had shaped some plasticine to block the gap where I'd cut the side of the container. This allowed me to fill the container to the top which covered my hand completely. Separating the two halves of the mould was a bit tricky as I didn't want to flex my hand too much in case the plaster cracked. Anyway I allowed loads of time and took it slowly and eventually the two halves separated.

 

As you can see on the inside of the top half the plaster captured a lot of detail.

 

It's hard to tell from the photos but the joint line of the two halves isn't  really along the centre of the hand - re the profile. This is because the plaster was starting to set on the lower half and I had to force my hand into place, which pushed away the plaster around the edges (contour). If you notice on the top-half mould that there are ridges around the edges. Hopefully this won't cause problems later on.

 

 

The next step is to make an armature. For this I'm using plastic 'Rawl plugs' which can be bought in lengths (roughly 300mm). This is like a hollow plastic tube but it's rigid enough to maintain straight cylindrical shapes i.e. finger bones, and can be threaded with wire (to link together). What I did for each finger was to measure between the bones on my fingers, and cut corresponding sections of tube. You can get the gist of it from the photo below.

 

I cut the sections of tube at angles - roughly 45 degrees - so that the joints could be bent after casting, without stretching the silicone.

 

The fingers, and thumb, sections are all cut to size and threaded on the wire.

 

I have applied some liquid latex to the plaster as an 'outer skin'. I'm hoping this will add more detail as the silicone I'm using can have fairly unpredictable results. It's funny how the top image seems to show the hand in 3d.

 

 

 

So that the gaps between the angles of the tubing won't get filled with silicone - which would prevent them bending - I covered each one with masking tape. I don't know if it'll work but it's all I can think of at the moment.

 

Luckily the gap positions are obvious as they need to be aligned before the fingers are set in place.

 

I drew out a template of my hand on a sheet of paper so that I could place the fingers as accurately as possible. I placed upturned masking tape on the paper to hold them temporarily, before gluing them together.

 

I used hot-glue to form a brace across the knuckles and again near the wrist.

 

As you can see the armature is fairly stable.

 

There isn't enough of a bend in the joints to be realistic, but I think I could still animate this much movement.

 



 I just discovered a major flaw in the armature. I'd braced the fingers across the first row of knuckles - at the hand - not realising that they won't be able to bend due to the amount of glue.



 

 



 So I had to cut off all the glue from there and re-apply it closer to the wrist. There is now a better range of movement overall.

 

A quick test of how the armature fits into the mould.

 

This is the type of silicone sealant I will be using. Unfortunately it's not very viscous, it kind of has the same consistency as toothpaste - and it doesn't set without exposure to air, similar to the liquid latex. So I will have to build it up in thin layers as opposed to joining the two halves of the mould and pouring it in. It also takes a long time to set so this will take a few days and a lot or guesswork to get the volume correct.

 

I pit several marks around the outside of the mould so that when the halves are joined together they will match-up in position.

 

Starting to apply the silicone. It's coming out of the tube in a thin bead so I don't know how smooth the end result will be.

 

After several layers of silicone I've finally placed the armature in position. Hopefully the silicone will secure it in place.

 

In the image above you can see that the latex outer skin is starting to peel away from the mould. Maybe the next layer of silicone will push it back into place. Next I'm going to start applying layers to the top half of the mould. It's beginning to look like I will have to stick the two halves together as opposed to any kind of 'poured' cast.