Hello all!

  I am in the process of making a 12 inch tall 1:6 scale silicone puppet, and have reached a point where I have several questions, so forgive the length of this post.

To start, here are a couple of pictures of my armature and the sculpt:

After several months and a couple of wasted attempts at mold making, I am about to begin work on what I hope is the final mold for my character. It will be made from ultracal30. Ron Cole has a great mold making video, but at the beginning he mentions its for a foam latex puppet, but i imagine the same method can be used to make a silicone puppet.. are there any modifications that would need to be made? Im debating between the horizontal cast seen in the link just below, and the vertical cast as seen in Ron Cole Mold-Making tutorials on youtube. I have been taking bits and pieces from several mold making videos, especially Ron's and this one...


Whats the best way to mold/cast my puppet, especially with regard to floating the armature in the mold cavity? 

 Because my character will be wearing a short sleeved shirt, I would like to cast the entire puppet as one piece to avoid seams... arms, head and all...  but it seems there is not good way to suspend the armature in the cavity when the arms (and possibly head) are attached to the armature.   

   It looks like Laika casts horizontally, and suspends their armatures by having their arms and legs removed and locking the body in place with miniature blocks and rods that fit perfectly inside the mold (See picture below). Is this considered the ideal way to cast silicone? 

It seems the issue of hiding seams of attaching the arms to the body is nonexistent for Laika's puppet, because he will be wearing long sleeves.  But how would you attach separately cast arms (or a head) to a puppet without hiding behind long sleeves. Will silpoxy, the silicone adhesive from smooth-on, allow me to simply glue the pieces to each other and then hide the seam with silicone? 

    I am also considering removing the head and casting everything vertically in a two piece vertical mold as shown in this picture of a puppet made by Nick Hilligoss. 

It seems this vertical "Pour through the neck hole" would be the easiest way to float the armature inside...  Does the shape of my puppet present any problems with air bubbles collecting in any areas?

I have watched Ron Cole's mold making tutorials on youtube, but am wondering if the same method can be used to cast a silicone puppet, and if so will i hate my life for trying to cast the puppet with the armature's hands attached? Would i need to paint the inside of each piece with silicone to give a a skin before i pour in the remaining silicone?

One final question! I have heard many people praise platsil gel 10, but it has a 6 minute pot life... too short to degass and pour i imagine... Is degassing necessary with platsil gel 10?  It seems i would need a longer curing silicone to degass and eliminate air bubbles, perhaps a tin silicone.  any suggestions on casting material? I have messed with soma foama and its 30 second pot life makes it unusable for me, i am leaning toward plastigel 10 but am open to other suggestions

Ultimately, my questions are these...

What is the best way to create a mold for my puppet that will allow for floating the armature inside? Could me puppet be cast as one piece? If not, how does one go about hiding the seams created by attaching a separately cast arm (without resorting to long sleeves).  and finally... is degassing ideal when using platsil gel 10? Any other flexible silicones with longer pot life to allow for degassing?

Thanks to everyone on this awesome forum!

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For those areas which might have issues with air bubbles, you can always make small batches and pre-fill e.g. the ears or lips. I did this with some toes on my latest mould as they trapped air the first time round.

Remember it's not an either/or option. You can do the initial filling horizontally, to make sure you have got the silicone into e.g. the fingers and other extremities, and about 90% of the overall fill, then clamp the mould together and finish off with the pouring. Not forgetting the retarder and maybe a bit of deadener, which thins the silicone and makes it a bit more pourable (and softer).

When doing the initial coating/skinning in the mould, take care to clean off any bits of silicone that spill onto the mating surfaces of the mould, or they will prevent it from coming cleanly together for the final result.

Thank you for your help Simon, I have yet to begin the process but your method sounds like a great compromise and I plan to execute just as you've said.  

  I would love your continued help as I begin, if that's possible. If I run into any questions or issues I will post them here.  Stay tuned if you'd like as ill update this thread when I attempt the process in the coming weeks.

Yes, no problem. I usually check out the forum a couple of times a week. If you can post some pics as you proceed, that will be good. Your first task is to get a decent mould. I notice the armature pic has shorter 'feet' than the sculpt. It would be good to have those extensions in the mould, so they can locate the leg armature neatly when you come to casting the silicone. 

If you haven't finished the sculpt yet, it might be worth considering making the fingers slightly fatter. They look a little thin to me, and this will make it harder to cast the fingers successfully.

Hey Simon!
It took me forever but i finally followed your guide and constructed a mold to cast my silicone puppet. I thought id share an update, and hopefully get some more advice from you.

I mounted my model to a platform made of Perspex, then screwed the platform to my work table. This held the puppet level horizontally. I was then able to surround my model in Klean Clay, and surround him in a Mega Blocks coffin. I left the bottom-of-the-foot holes open for technical reasons. I plan to attach the perspex base, on which my ball and socket armature will be mounted, to the bottom of the plaster mold, to act as a floor/base, and to prevent silicone from leaking out of the feet holes when I pour it into his head spout.

Pouring the plaster first half of the mold went very well. The next day I flipped him, removed the Klean Clay surrounding the sculpt and cleaned up the plaster using rubbing alcohol, paper towels, and sculpting tools. Next, I mixed Petroleum Jelly with Mineral Spirits and painted 3 layers of the mixture onto the first half of the mold to act as a release agent.
   Pouring the second half went pretty well, but I did have some minor issues I don't know if i should be concerned about....
   As you can see in the picture below, the second half of the mold developed a discoloration over most of it. I doubt its because of my mineral spirits/vaseline mixture, as the castable mold cavity itself also has it and i used no release on the sculpt. I carefully measured my plaster and water ratios, but mixed by hand so maybe it was a mixing issue... Anyway, the mold surface feels plenty sturdy, but the discolored area (including the actual castable part of the mold) feels slightly more textured than the first half I molded. Is there some sort of sealant I could apply prior to casting my puppet, that is silicone friendly, and would give the two mold surfaces a more uniform and similar surface texture? The texture difference between the two surfaces is not much, but I just want to ensure that my cast doesn't have two different looking halves.

   Another issue I had, as you can see in the picture below of the hand and arm, is that bubbles formed in some spots in the plaster right along the edge of the sculpt (as seen below). I realize now that this is probably due to me not using a brush to go along the edge of the sculpt, and instead relying only on blowing through straw to eliminate air bubbles trapped in the plaster along the seamline. If necessary, I plan on filling these holes with tiny bits of "Oatie" plumber's epoxy. Are these bubbles going to cause major issues while seaming up my silicone puppet after removal from the mold? After cutting away the excess and removing these blobs along the seam, how much can be hidden by painting more silicone over the seam?

Thank you very, very much for your continued help. I really appreciate it!

Hi there! Good progress, coming along really well.

Looking at your 2 issues. I can't see very clearly in the photos, bit it looks like there may have been some clay in the plaster, as it is over both the mould surface and the sculpted areas. One way of finding out if this matters would be to put a blob of coloured silicone into each half, then compare them. The reason I say this is that colour tends to obscure texture, so it may not matter at all.

Hopefully it will be acceptable, because otherwise you may need to start over. Be absolutely scrupulous in keeping plaster, clay etc etc separate, and always mix plaster in clean bowls! 

Or...and I have never done this, it might be possible to use a thin wash of e.g. Polyfilla to try to fill the tiny cavities. The problem here is that it will tend to seize as the water gets sucked out, so may not be a solution. Experiment on the mould surface, where it doesn't matter. Another possibility might be to use a heavily thinned wash of clay, as in Chavant, as the plaster will not suck water out of it. You might be able to very gently apply this (brush, sponge?) to improve things. The problem with both of these methods is that you risk making things worse, by adding more unwanted texture and possibly creating unsightly seams

Lastly, I assume your character will have some clothes? So you only really need to concern yourself with areas of exposed skin, and can forget about the rest.

As for the little bubbles, I generally don't pay much attention to them. They come up as raised blobs in the final cast, and you can easily hold them with tweezers to cut them off. Filling with epoxy putty is also good, so it's a case of work now or later! And yes, brushing right into those corners is essential - I skipped this stage recently, thinking blowing would suffice, and ruined the mould. Had to start all over again! You get some little bubbles occasionally even with brushing, but I had great craters!

Have you seen this video, where John Ikuma shows the technique of smoothing seams with a Dremel and Vaseline? It's at about 26:00. Bear in mind that he is using tin-based silicone.


Anyway, great progress. Keep us updated!

Oh, something else to consider. You will need to ensure that the perspex and the plaster mould are well sealed, otherwise there is a risk that all your silicone will just pour out of the bottom of the mould. You may find that a plaster jacket will help here. Basically, you will need to ensure there are slopes wherever plaster meets plaster, otherwise it will lock together. Then you assemble your mould,fix it feet uppermost, put blobs of clay over any protruding screws, and build some walls outwards and upwards. You then pour a plaster jacket or cup, that will hold the mould together and should prevent leaks. But beware undercuts - think very carefully before casting the plaster!

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