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Well here's the situation, I have some rather large personal models I wish to cast, problem is currently I'm using micromark resin which I've heard has a tendency to shrink with larger casts. The objects are 4x4x2" on average so they're fairly large. Does anyone know of a good resin for large projects that won't shrink and hold it's shape under moderate weight?

General information, I need pieces not to warp under about a kilogram or so of pressure, it's about a foot and a half humanoid model and it'll suck when one leg ends up shorter than the other after a year or so of standing.

We also need the resin to have a pot time between 5 and 15 minutes, the longer the better, I use a vac chamber to degas the molds so I need time to hit it once or twice before it begins to set.

Try emailing Alumilite.
I've got friends in the FX industry who swear by their stuff (I'm not in the US, and the products I would recommend from experience would probably not be available).

Smooth On makes a good line of casting resins.

Smooth Cast 321 should give you the pot life you are looking for.
http://www.smooth-on.com/Urethane-Plastic-a/c5_1120_1210/index.html

chromedog wrote:Try emailing Alumilite.
I've got friends in the FX industry who swear by their stuff (I'm not in the US, and the products I would recommend from experience would probably not be available).

I will have to give them an email, only issue with their stuff is the pot time which usually isn't over a few minutes. But maybe they have a retardent or something to slow it down a bit.

RanTheCid wrote:Smooth On makes a good line of casting resins.

Smooth Cast 321 should give you the pot life you are looking for.
http://www.smooth-on.com/Urethane-Plastic-a/c5_1120_1210/index.html

wow, the site has a wealth of info on it's product, seemingly absolutely what I was looking for. Large scale low/no shrinkage at larger scales, wow this might be perfect, now if only they sold 2 gallon jugs cheaper.

I'd second smooth cast, if you bake it right after it sets (I think at 160 Fahrenheit, it'll come with instructions) it should be plenty strong too.

Requia wrote:I'd second smooth cast, if you bake it right after it sets (I think at 160 Fahrenheit, it'll come with instructions) it should be plenty strong too.

Hrm didn't see anything on the site about baking, I figured it was a set resin not a cook. I'll have to do a bit more reading then.

It is set resin. The baking is done after the parts are removed from the mold. It's not necessary, but it makes for stronger parts.