Molding a large rubber costume; plaster, resin?

[yodasmeagol]

I am planning to build a large monster costume. I will sculpt the pieces from clay individually, the torso, the legs, arms, and head. The final product will be a latex suit.

My question is what would be the best way to mold my sculpted pieces? I'm thinking of using traditional 2-part plaster molds. The main issue I foresee is size. The torso especially, which will be somewhere around 1 by 2 by 3 square feet. I might be able to coat the entire sculpt in plaster, leaving the neck, arm, and leg holes open so I can empty it out. I'm also worried about dividing walls for the mold; these pieces might be too large to really be able to coat the entire half in plaster.

I've also thought of using resin/fiberglass molds. That could be easier in a few ways; not as thick of a build up needed, less fighting against gravity, lighter molds. But I'm not sure how casting latex inside would work. I have heard that it is possible to cast latex inside of a resin mold, but it is tedious.

Anyone have any advice on how to mold large pieces for casting latex? Without blowing the budget too high?

 

[Gorgot3000]

I know the latex doesn't cure into a silicone mold , and the best way is by using plaster mold because plaster will absorb the humidity of the latex .

What about using a thin coat of paris plaster, adding some plaster strips or fabric mesh on it and pour again paris plaster on it ... Like this you will have a 1 inch thick mold and stronger than just using plaster into a "box" .

If it was me , I would use 2 mold parts ... one front , one back piece, making a some kind of overlap and glue the 2 pieces with latex .

Joe

 

[thenewpanther]

I am planning to build a large monster costume. I will sculpt the pieces from clay individually, the torso, the legs, arms, and head. The final product will be a latex suit.

My question is what would be the best way to mold my sculpted pieces? I'm thinking of using traditional 2-part plaster molds. The main issue I foresee is size. The torso especially, which will be somewhere around 1 by 2 by 3 square feet. I might be able to coat the entire sculpt in plaster, leaving the neck, arm, and leg holes open so I can empty it out. I'm also worried about dividing walls for the mold; these pieces might be too large to really be able to coat the entire half in plaster.

I've also thought of using resin/fiberglass molds. That could be easier in a few ways; not as thick of a build up needed, less fighting against gravity, lighter molds. But I'm not sure how casting latex inside would work. I have heard that it is possible to cast latex inside of a resin mold, but it is tedious.

Anyone have any advice on how to make mold large pieces for casting latex? Without blowing the budget too high?

I agree with the plaster of paris idea, it's cheap and you can buy a large quantity for little money, I think amazon sells a 25lb bag of plaster for about $10