Posts Tagged “Mould Making”

I’ve done the first cast from the werewolf mould. I’ve previously only made pour and injection moulds, this time round I’m pasting the silicon into the mould as the silicon I’m using (Tinsil) has a thixotropic agent which you can use to thicken it up enough to make it brushable. This was then backed up with a layer of fibre glass to support it.

Brushing in the silicon has led to more air bubbles than usual, but that’s not too difficult to fix – as this is a tin based silicon I can use silicon bathroom sealant to fill in the gaps as it’ll bond to it.

I may do another cast and be a little more careful this time round though. I’ve also found you can make the silicon really stretchy by adding an equal amount of ‘deadener’ so that might be worth a go.





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I’m still working on the old dude – I’ve added an arm to him now.  This thing is getting mahoosive!  Should’ve thought through how big a 2/3 scale puppet would be before I started really ;0)

In other news I’ve also finished the molds of the werwolf.

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Couple of bits.  I’ve actually taken a slight break from doing the werwolves as I’ve been ebaying a load of stuff so I could buy a new camera to shoot the final vid on.

That’s all done now and I’m the proud owner of a Nikon D90 which (for all you cameraphiles out there) is a digital SLR which also shoots 720p vid. The advantage of this over a regular camcorder is you can use your SLR lenses to get some excellent video effects. Here’s some test vid using an f1.8/35mm lens.

I’m also starting to make the molds now- partly because I’ve run out of clay halfway through building the old man so I need the clay from the werewolf sculpt.

Here’re some pics of the old man:

And here’re some pics of the molds:


I’m laminating the plaster with glass fibre to give it some structural strength.

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I had intended to post some casting pics when I was doing the zombie mask but didn’t quite get round to it, so I thought I’d do it here.  The sculpture was done over the same head as the zombie mask:

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The two halves of the mold are placed over the ‘core’.

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Silicon will flow through the mold within the cavity between the core and the outer pieces of the mold.

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The two halves of the mold are then bolted together and ‘bleed holes’ are drilled.  These will allow air to escape the mold as the silicon is injected so that air bubble do not form.

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The molds then turned upside down and a large syringe which I made out of drain pipe is inserted into a cavity within the core.  The silicon flows into the mold through the top of the head and up through the interior.  The bleed holes are blocked off with blobs of clay as the silicon reaches them.

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Once the silicon’s set the mold is cracked open.  Here’re some pics of the silicon cast fresh out of the mold and also with a coat of flesh coloured paint.  It doesn’t look quite so orange in real life, think it’s the flash that’s done that!

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The painting’s not finished but I’m quite pleased with how this has turned out so far.  Painting silicon is abit of a pain and it’s only recently that I figured out how to do it – there’s very little info out there detailing this.  The only thing that sticks to silicon is silicon, nothing else will adhere, so if you use any type of regular paint it will either not dry or flake off once it has.  You therefore need to actually paint the silicon with silicon.  You can’t actually buy silicon paint (well that’s not technically true – there is one company that I know of that does it, but it’s quite expensive) so what you need to do is mix a pigment with silicon and use that as your paint.

I’ve found the best way to do this is to use silicon bathroom sealant mixed with oil paints and thinned with white spirit.  As the bathroom sealant cures it will chemically bond with the rubber making your pigment part of the piece.

This works well with the silicon I’m using as they’re both tin based silicons.  Some silicons such as Platsil, which is used extensively in the FX industry, are platinum based so I’ll need to experiment to see if this method will work with those.

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So I’ve been working on the zombie mask.  Here’re some pics of the mold:

Not pictured is a ‘core’ which sits inside the two pieces of the mold.  This is roughly the shape of a head.  Left is a pic from a previous mold I made, same principle though. Inside this is a….. ‘socket’ I guess where a large syringe fits. This is constructed from drain pipe – unfortunately you can;t buy syringes of the necessary size (about 2L) so I had to make one.

I’ll try and post some pics of all this abit later on as I’m fairly pleased with how it all worked (mostly because it did work!) The silicon is then injected into the cavity between the pieces  and ends up looking something like this:

This isn’t quite finished yet – the top set of teeth are missing and there’s some more painting to do, particularly at exposed skull bit on top of the head, but very nearly there.

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Not posted anything in awhile, mostly because I’ve been crazily busy. Work on the film continues, which I’ll post separately about. I’ve also been hired to create some silicon rubber masks, one of which is pictured below.

This will be cast in silicon rubber.

This is the first of several.  In addition to sculpting the pieces themselves I’ve been teaching myself mold making 101 as I’ve gone along pretty much.  These masks have required two piece fibre glass molds plus an interior core and are the largest molds I’ve made to date.  Here’re some pics of the sculpture ready to be molded:

As well as making the molds themselves I’m having to build the tools to use them.  I need a huge (around 2 litre) syringe to inject the silicon rubber into the mold.  Of course you can’t buy anything like that so I’ve had to make it.  I’ve come up with something made of drain pipe tubing and fittings.  There’s a seperate cap and plunger so I can vary length of tubing used (and thus the volume of the syringe) to accommodate larger molds – if you need to inject more material simply use a longer length of tubing.

Fingers crossed it works….;0)

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So here’re some pics of a cast coming out of the mold.


And here it is with the beginnings of a paint job on it.

I’m using a mixture of translucent silicon bathroom sealant, white spirit and oil paints to paint the cast. These seem to be working pretty well.

Next step is to make a fibre glass skeleton to go inside the rubber skin and make some mechanisms to make it move.

I’ve bought a ton of watch and clock bits and pieces to help. These are as much for aesthetic effect as actual use!

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So here’s the second part of my mold for the oldroid taking shape. I’ve filled in an area with clay. This will create a cavity in the mold which will later be filled with a plaster core.

So next up is to apply a second layer of resin and fibre glass. First a layer of vaseline is applied to act as a seperating agent.

Once that’s done several layers of resin are applied same as before.

Once that dries you have to slowly seperate the two halves of the mold. This is abit of a painstaking process. You just need to slowly work it apart. A screwdriver is usually the best thing to use.

Next bit is to clean the mold out.

Once that’s done clay is laid into the mold. This represents where the rubber will go during casting.

I’ve also added two cables. This will create channels within the core to allow silicon to be injected and air to released during casting.

The mold is then clamped together and plaster is poured in.

Here’s the finished core. With the clay removed there’s now a cavity which is where the silicon, once injected, will sit.

Next step is to cast up the puppet!

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I’ve finally finished the sculpt for my clockwork android, or ‘oldroid’ (0.L.Droid). Here’re some pics:

I’m quite pleased with the way this one has come out and have now moved on to making a mold. Here’re a few progress pics:

First, I’ve covered the back of the sculpt in polythene

It’s then laid in a bed of clay

The edges are lined up with the sculpt and brushed down with water. This is to make the seam lines as small as possible.

Next step is to give it a coat of resin. I won’t go into how to mix it up, but basically you add a set % of catalyst to set it off.

I then dripped the resin all over the sculpture using a brush.

Once that had hardened I got some thixotropic resin which is basically a viscous type of resin that doesn’t drip.

I used this to fill in any gaps and undercuts.

Once that had hardened I added another layer of resin, this time with glass fibre to reinforce the existing layers of resin.

Once that had all hardened I flipped the mold over and started cleaning out the layer of clay.

This is a pain in the arse to be honest, however I found a way of doing it that was a little easier and also (more importantly) risked less damage to the sculpture; I turned the shower hose on it and used a brush to lightly brush away the clay as it became saturated with water. As Chavant is oil based this didn’t damage the sculpture.

This was a lot easier than picking it out with a sculpting tool, although I had to sit in the bath to do it and got soaked, still we must suffer for our art ;0)

You’ll notice there’s still some clay left in the mold. That’s deliberate, this mold is going to have a core, so i’ll be building up some space for that when I come to do the second half of the mold.

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