Can EVA Foam survive Water?

So I just would like to know if Foam Costumes can survive heavy rain or something? Could Plasti Dip help it?

As far as I'm aware, certain foam mats are designed to be spill resistant and are made from materials that don't absorb water. That said, you're more or less referring to the idea that your foam matting will endure prolonged periods of water exposure, and while I'd assume that a coating would help the foam resist water a little better, it would still end up soaking up moisture and suffering.

Foam is a good, cheap alternative to the Pepakura process - just be sure that you have somewhere to shelter if you're going to get rained on.

Sealing the entire piece in Plasti-dip, Flex Seal, or similar type rubber coatings should provide adequate water-proofing to the foam itself, however the paint (as well as any decals or other accessories added after sealing) will still potentially be susceptible to water damage. Two or three layers of clearcoat should help protect the paint. Be sure to look for "exterior" or "weatherproof" on the can, or ask someone knowledgeable whether or not the paint is made to withstand weather exposure, as there are clear-coats that aren't really designed to be anything more than mild dust and smudge shields.

The downside here is that you have to coat the entire surface, inside and out, to make it truly waterproof. If you just coat the outside, the water will soak into your clothing/undersuit, run down the inside of the armor, and soak into the foam from there. While EVA floor mats, as Arcanine pointed out, are typically designed to resist moisture, 1) much of that is in the outermost layer, so if the foam has been scuffed, sanded, or by any other means the surface has been broken, that will undermine the protective layer, and 2) this protection isn't so much "proofing" as it is "resistance," which means while it won't drink up moisture like a sponge, it can soak through and it was not intended for the foam to be submerged or exposed to prolonged periods of dampness. More or less it's designed so that if you spilled something on it you could just wipe it up without having to worry too much about lasting moisture damage or staining.

But if you're only wondering if your foam build will be safe if you get caught in the rain and it takes a few minutes to find shelter, it should hold up well enough but I would recommend drying it off at your earliest convenience, especially if the clothing underneath has gotten wet as well.

The clear coat stage is usually used in conjunction with body fillers and the like, so you won't have any problem finding the stuff. The aerosol stuff should be adequate for your use (although if you have a compressor handy then the tubs work even better), just don't be stingy with it and apply it liberally. At least two cans of the stuff, the surface area of a complete suit would be enough to rival a large motorbike maybe several.

Zaff said:

Sealing the entire piece in Plasti-dip, Flex Seal, or similar type rubber coatings should provide adequate water-proofing to the foam itself, however the paint (as well as any decals or other accessories added after sealing) will still potentially be susceptible to water damage. Two or three layers of clearcoat should help protect the paint. Be sure to look for "exterior" or "weatherproof" on the can, or ask someone knowledgeable whether or not the paint is made to withstand weather exposure, as there are clear-coats that aren't really designed to be anything more than mild dust and smudge shields.

The downside here is that you have to coat the entire surface, inside and out, to make it truly waterproof. If you just coat the outside, the water will soak into your clothing/undersuit, run down the inside of the armor, and soak into the foam from there. While EVA floor mats, as Arcanine pointed out, are typically designed to resist moisture, 1) much of that is in the outermost layer, so if the foam has been scuffed, sanded, or by any other means the surface has been broken, that will undermine the protective layer, and 2) this protection isn't so much "proofing" as it is "resistance," which means while it won't drink up moisture like a sponge, it can soak through and it was not intended for the foam to be submerged or exposed to prolonged periods of dampness. More or less it's designed so that if you spilled something on it you could just wipe it up without having to worry too much about lasting moisture damage or staining.

But if you're only wondering if your foam build will be safe if you get caught in the rain and it takes a few minutes to find shelter, it should hold up well enough but I would recommend drying it off at your earliest convenience, especially if the clothing underneath has gotten wet as well.

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Would it work if I used Plasti Dip as paint?

Aiden26 said:

Would it work if I used Plasti Dip as paint?

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I've thought of doing so myself if and when I can finally get into foam building. If you go with that method, I would suggest either doing a full base coat over the entire piece first to seal the whole thing, or top the whole thing off with a coating or two of the clear Plasti-dip. I haven't been able to test to see how well it would work, and I don't know how "clear" the clear Plasti-dip really is. If it's clear enough a careful buffing after it sets should make it more clear and thus won't obscure the details underneath, but I strongly suggest testing that on a scrap piece first just to be sure the results are something you'd be happy with.

The benefit of doing the top coat instead of a base coat would be the extra layer of protection for the color layer. If it gets scuffed or scratched, it has to go through the clear coat before it will affect the color at all. The downside is if there's anything floating around when you spray the clear coat, it can very easily get trapped in it, and then you'll have a speck that you can't get rid of without digging it out and redoing that area. Plus there's the possibility that sun damage or other contaminants could cause blurring, hazing, or yellowing in the clear coat. I can't say how likely or unlikely that is because once again I haven't had the opportunity to test it.

The reason I suggest doing either a full base coat or a full clear top coat is to make sure there are no gaps or breaks between one color and another. Just keep in mind, as Ballistic alluded to, there's a lot of surface area to cover, especially if you dedicate yourself to coating the entire suit inside and out. So 1) that's going to be a time consuming process, and 2) that can be a very expensive process, and that's just to seal the armor with the first full coating. If you continue to use Plasti-dip in place of regular paint to add details, markings, and so on, that's going to be significantly more expensive than just doing a base seal layer of Plasti-dip and topping it with paint. I don't know about the prices in your area but for me even an "off brand" rubber spray sealant costs $10-15 for a single can, with the name brands pushing closer to $20 per can, whereas spray paint runs between $2 -$6 a can.