There is addition cure silicone which is usually more pricey, and generally mixed in equal parts A+B. This gives a very realistic skin like feel and appearance with a semi translucence (stuff like Dragon Skin). I use quite a lot of RTV silicone which is preferred for making molds, however it is also relatively easier to use as it is less prone to contamination. e.g you cant have any trace of latex when working with silicones, but RTV seems to be more "robust". You can even use bathroom sealant silicones that come in the tubes that you use via a mastic gun. I actually use the bathroom sealant silicone with lighter fluid to paint my final pieces, and the bonus benefit is that you do not need to use catalyst which is harmful. I could not tell you for sure but I imagine Corpse Bride used RTV, I worked on Frankenweenie and I think they were using RTV there. I could not tell you what brand as I am unsure but it definitely felt more like RTV. Hope this helps
Oh actually i can show you the difference! if you look on my pictures, there are a number of heads that were created with addition cure 13 silicone, there is also three pictures of a devil head created with RTV silicone. The platinum silicone heads are finished whereas the devil is not and was just a test so the quality is not reflected. The hell imp in another photo is pretty much complete and uses RTV.
Thank you! That was extremely helpful and very informative!!
There are the one-part sealant silicones in a tube, which rely on some component evaporating into the air. I don't think they would work in a closed mould, but they do work for paint like Will said, and I did manage to cast some scutes - the raised scales along the back - to repair a lifesized silicone crocodile that had been chewed by mice. The moulds were one piece, open at the bottom so exposed to the air, and I didn't fill them all at once but built up in layers so each layer could cure first. Then I could stick them onto the croc's back with more silicone sealant. Once cured, they are firmer than I would like for a stop motion puppet.
One sculpting and mouldmaking shop I go to (Barnes products) identifies their mouldmaking silicones as Addition Cure or Condensation Cure. http://www.barnes.com.au/catalog/mould-making-c-105.html
This confuses me, because there are two different kinds of silicone where you mix two parts, one containing a catalyst, to make it cure. I would have thought both would be classed as Addition Cure, since you add something.
One type is Platinum Cure silicone, which appears to be what Barnes means. This covers some mouldmaking silicones, which come in a range of firmness but usually harder than you want for casting puppets or makeup prosthetics. It also covers the soft silicones like Dragon Skin and Ecoflex from Smooth-On, and Platsil Gel-10 from Polytek, that are used for casting puppets and makeup/animatronics.
Here are some platinum silicones at Compleat Sculptor in the US:
These are the silicones I've used for making puppet heads. Usually they come in Part A and Part B, and you mix them one to one.
But there is also Tin cure silicone, which is far less prone to being inhibited by materials like sulfur (used in many plasticines, and in latex) leaving traces on the mould. I would have thought that was still addition cure, since you add the two parts together. But I'm not sure, looks like maybe not. I would have thought Condensation Cure would refer to the one-part silicones in a tube, which stay like a thick grease until exposed to the air. But Barnes has Condensation Cure silicones where you add a catalyst, so I guess it can't mean that.
There are Tin Cure silicones in the US and the UK which are soft and suitable for puppet making. If you wanted to cast the puppet in foam latex, then trim it back and cast over the top in silicone, as done in Corpse Bride to keep the weight down, you would have to use a tin cure,because the platinum cure silicone will fail to cure if it comes into contact with the foam latex. I can't buy the tin cure silicones suitable for puppetmaking in Australia so I stick with Platsil Gel-10 and Ecoflex 00-30. I had to switch to Chavant Non Sulphur Plasticine for sculpting, since all my old plasticines contain sulphur, which stops the platsil curing.
To me, it is Platinum or Tin cure which is most important, since it tells me whether I have to avoid anything with sulphur in it coming into contact with the mould. The UK supplier of tin cure silicone for effects casting won't ship overseas, and I can't quite pin down what the stuff in the US is, but maybe someone knows what it is called and where to get it.
Ok, did a search and found this explanation about Condensation Cure (tin) and Addition Cure (platinum). Both fall under the general term of RTV - which stands for Room Temperature Vulcanizing.
It says the Platinum cure silicones can be inhibited (ie, they stay runny and never cure) by contact with tin, sulphur, or amines. I don't know what amines are. But I used some platinum cure PinkySil to make a texture stamp mould from the leathery texture on my Bolex and Canon DSLR camera bodies, and it cured fine on the Bolex, but the plastic on the digital camera stopped it curing. So maybe there are amines in some plastics.
What I do know is, you gotta test the Platsil on everything you might possibly use in the sculpting, mouldmaking and casting process to see if it stops it curing.
The one-part stuff in a tube can also be called Acetic Cure - you can smell the vinegary acetic acid coming off it when you squirt it out.
Yeah, as I recall when I was researching silicone I learned that condensation cure not only is not inhibited by moisture, but actually requires moisture in order to cure - thus the name. Don't remember why addition cure is called addition cure.
But enough silly terminology - nobody needs to know all that stuff.
The top tin cure brand I know of in the US is called GI 1000 (there are other numbers, I believe 1100 is one) and is made by or sold through Silicones Inc.
I always wanted to play around with this stuff, but it turns out when you order it you get an opaque catalyst, so the silicone ends up opaque, which of course is no good if you want to color it. You need a transparent catalyst. But I did hear once that if you contact them by phone or maybe email you can special order it with a clear catalyst. You just can't order it that way through their website.
GI-245 is clear tin based silicone from Silicones Inc. I've used it before. It's about Shore A 10.
One of John Ikuma's Stop Motion Magazine issues had an article where Georgina Hayns from Laika said that they used GI-1000 and GI-1100 as a base for ParaNorman; they'd apparently used GI-1000 on Corpse bride. It was frustratingly light on details.
Thank you all very much for your help!! I think I will go with Clear Catalyst GI-1000. Thank you again!