someone could advise the best method to achieve a silicone skin
as they did in the movie Fantastic mr.fox and Corpse Bride.
I know that inside the two halves there must be a head shape that determines the thickness of the skin, I do not know how to split the mold to allow the silicone chutes well without creating bubbles.
I have experience in making mold, I made puppets and limbs in full sillicone skin but I have difficulty with the design of the mold to the skin
Are you interested more in making silicone skin for heads, or for bodies too?
Here's a little behind the scenes clip from ParaNorman showing how they do it for the bodies:
Also look at Ron Cole's moldmaking tutorial: http://wobblytripod.blogspot.com/search/label/Mold%20Making%20Tutorial
Or wait - are you asking how to make a core mold that goes inside the mold? I think that might be what you're looking for. Ron also has another tutorial that demonstrates how to do that: http://www.vortex42.co.uk/isomer/index.html
I believe he covers it in that tutorial.
I've also heard of a technique where you first cast the head (or body) in foam latex, then snip away the outer surface (as they did to the urethane foam in the ParaNorman clip) and then put it back in the mold and cast a silicone skin around it. Of course this can only be done using a tin-cure silicone like the ones made by Silicones Inc (GI-1100 for example). The platinum-cure silicones like Dragonskin or Ecoflex are far too sensitive and won't set up properly against latex.
But something tells me none of this is what you're looking for.
"I know that inside the two halves there must be a head shape that determines the thickness of the skin, I do not know how to split the mold to allow the silicone chutes well without creating bubbles."
Hmmm yeah, you're looking for something more technical. Sorry, I don't know that kind of stuff. If you're lucky Ron or somebody who works with silicone will answer.
I have made core moulds for casting foam latex skins, usually for life sized heads, and the process would be similar. There are a couple of different ways, but the method I used was to use a layer of clay where the rubber skin would later go.
First I sculpted the head, and made a 2 part mould in plaster. Then I cleaned out the mould. I rolled out some plasticine to a thin sheet - for platinum silicones, you must use a sulphur free plasticine for this. I pressed a thin layer of plasticine into the inside of the front and back halves of the mould, then put the two halves together. With bigger heads it was easy to reach in to smooth the join between the clay halves, with a puppet head this might be more difficult.
Then I poured plaster into the mould, to make a solid core. Once it has set hard and is removed, the core can be carved and sanded if required. You might want little hollows in the inside of the rubber skin for mechanisms to fit, so you would sculpt those into the clay, creating bumps in the plaster core.
The other method is to start with a core, then sculpt the head in clay over that. Then make the outer mould over the clay and core. If you had a mechanism already built to go inside, you would probably want to make a core that matched it's shape.
It is important to have a place where the core and outer moulds touch - usually below the neck - and fit together, so the core always sits in the right place. Use registration keys to locate the parts. You also need a hole somewhere to pour the rubber in through.
For my silicone puppet heads, I don't make a hollow skin, I cast them solid. But I still use a block below the neck to register with the outer mould pieces, and hold the head armature in the right position during the casting. That would be similar to the bottom part of the core if I had one:
I don't think I quite understand your question ? Do you want to make a silicone skin for a puppet ? You have to be careful how thin you go with the thickness of the skin or your core ( inner part of mold ) will lock with the outer part of your mold . That is if your mold material is rigid ...like plaster or fiberglass. You can however get around this by making a flexible outer mold with support mother mold . You can cast silicone into silicone but you must take the necessary steps to release your mold properly . Hope this helps!
If you are on Facebook you can check out my project there
Thank you all for the answers
what I would like is a skin to be placed on a fiberglass skull and joints for movement.
I made a base (skull) on which I modeled the shape of the head with plasticine Chavant. Now I have to make the cast of the face and begin to study the photo
of Greygus. What I do not understand from the photos is how inject the gel 10 Platsil
properly if I wanted to get a unique skin like a glove.
next post I'll put pictures
Ok, you already have the core, the skull. Your plasticine is over the top. Does it have a base to keep it standing up?
You need to take a mould of the plasticine sculpt, but also have it go onto part of your core, down at the base. Make a front half and a back half.
You need a place to pour the silicone in between the inner core and the outer mould pieces. Maybe you can make a hole in the top or in the back, where the hair would cover the top of the head. Or maybe you can have a hole through the base in the bottom, to pour in through. Or maybe you can do what I do and have a removable base. Put some silicone into the face and put the core in. Rest it face down. Let it set so the core is held in place. Then remove the base (like in my video) and pour the rest of the silicone in. When it is set, open the mould and remove the silicone cast from the outer mould. Then remove the core from the inside.
It would help to see a photo of your sculpt. This is something you need to think about before you start.
thanks a lot for your advice today I'll post a images.
here the skull that I did
So you plan on sculpting the face on this core?
here images of the skull and head in plasticine Chavant.
Under the skull I created steps that can serve as a key for the two parts of the mold.
Maybe just follow the technique used in the video Paranorman: Enter the Platsil in two parts and with the central skull press it all together?
Maybe we need another type of keys or shape of the base?
Then exit holes also serve to release the excess Platsil?