Urethane does brake down quicker-- It normally is just used for the molds, but you know something, I am always going against what everyone says you cant do--- so I say go for it -- if it works, cool. If it doesnt, then you have learned something.
You die if you stop learning.
Let us know the results. May have to do a long term test as well to see the durability.
Urethane is stiffer that silicone, latex, or foam, breaks down faster, cracks more easily, and is really tough to paint. At the end of the day, it has few redeaming qualities. That is flexible urethane. I love rigid urethane for molds or display pieces, and the aluminum filled urethanes are awesome.
I prefer Silicones,rather than urethane rubber,or latex. The very best is Dragonskin,from smooth-on. Dragon Skin silicones are high performance platinum cure silicone rubbers that can be mixed 1A:1B by weight or volume and cure at room temperature with negligible shrinkage. Cured Dragon Skin is very strong and very “stretchy”. It will stretch many times its original size without tearing and will rebound to its original form without distortion. Also you can do a casting without an undercut in the back of the head,it dont need it,because its that stretchy. It is expensive,but i say it worth it,the casting is never rot,never shrink,tear with age and its easy to patch with its own material.
I think silicone, for the kinds of masks being made here, is a bit on the heavy side. Plus you need to add something like cotton or cheesecloth to it if you want to foam fill it to make a mechanical bond or the silicone could just peel off the foam. I have found the Dragon Skin series to be on the finicky side. Some of them are really stiff too.
Thanks for the input everyone. As far as the silicone option goes, I probably wouldn't go with that for a mask, the main reason being cost. I understand from Usurper that his silicone head weighs about the same as a latex one. I've found dragonskin finicky for moulding, but ultimately, it is sometimes the best option, given its pretty amazing stretch capabilities. it does eventually start to tear with age though, but it's held up better than I expected.
i just produced a Captain America mask in urethane, and have so far been pretty impressed with how easy the casting and painting went, hence my question. I'll see how that holds up before jumping into doing a pred mask.
Latex will most likely be cheaper, but it depends where you buy it. I find that urethane can degrade quickly. It is used for armor a lot on armor heavy shows like Stargate SG-1. Silicone can be really soft and floppy, more so than latex, without some kind of foam reinforcement, and you cannot easily ghetto fabulously back like you can the latex, so making a silicone mask comes with it's share of complications.