Resin/Rubber casting a craft foam prop?

G

GatorDave113

Jr Member
Hey RPF,

I've recently become interested in EVA foam prop making and I had some questions about what directions I could go with it. This made me wonder, is it possible to resin cast or rubber cast a EVA foam prop?

Sincerely,
Dave the Gator
 
Sure is possible. I have done it. You just need to make sure your foam item is solid enough not to warp or sag under the weight of the silicone mold and jacket. Small items (say pistol or hand held items) are easy. Helmets and larger items (like rifles) are going to be alot more challenging. Start small and move up to larger items as you skills improve. That way the mistakes you make are not as costly!
 
OK, sweet! As far as keeping it from sagging or warping, do you think having some framing inside the EVA prop like pvc or armature wire would work?
 
GatorDave113 said:
OK, sweet! As far as keeping it from sagging or warping, do you think having some framing inside the EVA prop like pvc or armature wire would work?
Click to expand...

Framing, bracing, small rodents holding it up, Viagra, magic, anything you can think of to keep it stiff. If you can flex it with two fingers it probably needs more support. The plastidip will help as well but don't count on it to do too much. Err on the side of more is better.
 
Psicorp7 said:
Framing, bracing, small rodents holding it up, Viagra, magic, anything you can think of to keep it stiff. If you can flex it with two fingers it probably needs more support. The plastidip will help as well but don't count on it to do too much. Err on the side of more is better.
Click to expand...

Awesome, thank you so much! Now, I know when using certain materials in resin and rubber casting they can heat up during the curing process. Is that something that could affect the foam prop? If so, is there a way to coat the prop where the heat may not affect it as much?
 
GatorDave113 said:
Awesome, thank you so much! Now, I know when using certain materials in resin and rubber casting they can heat up during the curing process. Is that something that could affect the foam prop? If so, is there a way to coat the prop where the heat may not affect it as much?
Click to expand...

If you are using silicone for the mold, you are fine. It does not heat up much at all. The resin you pour into the silicone mold can heat up but your foam will be gone at that point so no worries. If you are making a jacketed mold over the silicone you fiberglass or plaster can heat up but since it is pretty thin and buffered by the silicone that should not be a problem. I have not had any heat related issues.
 
Psicorp7 said:
If you are using silicone for the mold, you are fine. It does not heat up much at all. The resin you pour into the silicone mold can heat up but your foam will be gone at that point so no worries. If you are making a jacketed mold over the silicone you fiberglass or plaster can heat up but since it is pretty thin and buffered by the silicone that should not be a problem. I have not had any heat related issues.
Click to expand...

Sweet, thanks for all the help! Now, I've never bought this kind of stuff before where would you suggest I go to get the stuff I need to get started? What kind of price do you think a beginner should expect?
 
Smooth-On offers some starter kits with all you will need to make a mold/jacket and cast a few items. They are a good online retailer and a fine place to start. Begin with a small item (hand sized) and move up from there. The kits range from $40 to $100 for a small item. Later, you can move to buying in bulk and save some money. The shelf life of some of the materials is less than a year so don't over buy until you a ready to use the materials.

Good Luck and post pictures of your process! If you think you are stuck just fire off a question. most everyone here has been in your shoes and should chime in to help you avoid some pitfalls.
 
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