Hey guys, I'd appreciate some help. So I'm working on an ODST build with EVA foam and hot glue. I have several pieces crafted, and I am looking for options on prepping and painting. I've heard of construction caulk, plastidip, or just nothing etc. as far as the seams and coating. Caulk sounds overly messy and dumb, and plastidip doesn't really impress me. Is anything needed if I don't have any open seams? Also, is general spray paint I can find at walmart okay? I'm not sure about the coverage on foam, or if I should use that 2 in 1 primer/spray paint. I would really appreciate insight on those who have used this before. Thank you!
Prepping foam to be painted?
- Thread starter Rahksi
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If you do go bare on the foam, I wouldn't bother priming, honestly. I was not impressed or convinced that it added any effect worth the cost. If anything the primer provided more problems in my testing, but I was trying to do it reeeaallly cheap lol
For sealing, you might look into auto-body spray / undercoat spray.
http://www.homedepot.com/p/Rust-Ole...zed-Undercoating-Spray-Paint-248657/202097745
As far as I can tell it is dirt cheap in the USA and I've been happy with the results. It's less rubbery and more of a shell, so if you go too thick it will fracture, but leave little more than hairline cracks that aren't visible unless you really strain the part. Just another way to go that you may not have seen, hope you find what you're looking for!
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^plasti-dip won't harden a piece, the whole point is that it retains its flexibility.
For sealing, you might look into auto-body spray / undercoat spray.
http://www.homedepot.com/p/Rust-Ole...zed-Undercoating-Spray-Paint-248657/202097745
As far as I can tell it is dirt cheap in the USA and I've been happy with the results. It's less rubbery and more of a shell, so if you go too thick it will fracture, but leave little more than hairline cracks that aren't visible unless you really strain the part. Just another way to go that you may not have seen, hope you find what you're looking for!
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^plasti-dip won't harden a piece, the whole point is that it retains its flexibility.
it is true that when using spray paint alone the colour will not come through as well without considerably more paint. This is primarily due to the huge difference in surface area between raw foam and sealed surface. In terms of adhesion or sensitivity of the bare foam to certain paints you shouldn't have any problems unless perhaps you dive into some more obscure brands/products. Same goes for almost anything you might choose to seal the foam with; mod-podge, plasti-dip, elmers, and under-body spray have all proven resilient to a variety of sprays.
Edit: realized I forgot your primer question. In my tests primer didn't seem help because the surface area of the porous foam is the problem. It really just sucks it up with out adding much, but then I also had to worry about compatibility between primers and paints, so it just isn't worth the trouble of using proper paint technique for a result that is inherently imperfect. IMO
TL;DR - I would seal with something, it makes painting worthwhile.
Edit: realized I forgot your primer question. In my tests primer didn't seem help because the surface area of the porous foam is the problem. It really just sucks it up with out adding much, but then I also had to worry about compatibility between primers and paints, so it just isn't worth the trouble of using proper paint technique for a result that is inherently imperfect. IMO
TL;DR - I would seal with something, it makes painting worthwhile.
A lot of people choose to seal the foam with caulk or Plastidip because without it, the foam will absorb a lot of paint...and as Noble 10 mentioned, it will take a lot of coats to get the color to show. For me, it was definitely worth it to seal the foam first with a couple light coats of Plastidip. I haven't tried spray paint, but I know that acrylics work well over the foam and Plastidip (no chipping/cracking/etc).
Ashuraa
Research Team Lead
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I have been using Envirotex pour on resin. Two thin coats of it on my armor made it quite a bit harder, not immobile hard, but very stiff. Paint went on beautifully. It basically put on a layer of hard resin. It did not eat into my foam or anything. I am really impressed with how it came out. The only caveat I have is that you have to use it in a warm place. Thankfully it does not put of fumes like fiberglass resin. You can also sand the envirotex resin after it has hardened. This means that once you put your paint on, you can sand it down a bit to make it look more weathered. The other thing the envirotex did was help fill any little imperfections I might have had in. It also help bond all my pieces together more, so that even if for some reason my hotglue melts, my peices will not fall apart.
I buy my envirotex from Hobby Lobby. Here is a link to the product.
I buy my envirotex from Hobby Lobby. Here is a link to the product.
Absol898
Active Member
Here is the link to the Help for foam: http://www.405th.com/f21/help-foam-38589/
the 5th post down is the method I used on my foam NCR ranger build. You wet a sponge (squeeze it moist), add a little latex caulk to your piece, and spread around with the sponge. you should have a thin white, almost transparent, layer. a tube of DAP latex caulk is like $0.99 a tube. If you did good making your piece from foam and do not need any bondo work, this is the way to go. After I did this I primed and painted and it worked perfectly. I used this method after I made my piece. doing before will damage the seal.
As for hardening foam, I was under the impression the point is to have it remain somewhat flexible, since it would be more comfortable. The point of plastidip is to seal for prime/paint.
If you do not seal the foam then the foam absorbs the paint and looks incredibly ugly and unrealistic. (you can test it yourself).
Hope this helped!
the 5th post down is the method I used on my foam NCR ranger build. You wet a sponge (squeeze it moist), add a little latex caulk to your piece, and spread around with the sponge. you should have a thin white, almost transparent, layer. a tube of DAP latex caulk is like $0.99 a tube. If you did good making your piece from foam and do not need any bondo work, this is the way to go. After I did this I primed and painted and it worked perfectly. I used this method after I made my piece. doing before will damage the seal.
As for hardening foam, I was under the impression the point is to have it remain somewhat flexible, since it would be more comfortable. The point of plastidip is to seal for prime/paint.
If you do not seal the foam then the foam absorbs the paint and looks incredibly ugly and unrealistic. (you can test it yourself).
Hope this helped!
RobTC
Member
What I've learned about EVA finishing and how I intend to proceed once I start using it, barring new contradictory information:
Smoothing foam faces: brief passes with a heat gun. It'll become shiny as the cells close.
Smoothing foam joints: 1) make good joints, slowly closed with BARGE contact cement. 2) silicone caulk with blended acrylic paint of the foam's colour (probably black). A few drops of paint should be sufficient, in theory.
Sealing foam for paint: Plasti-Dip or Rustoleum underbody spray both work and retain flexibility. Underbody spray is way cheaper in the US. If you have a good size compressor, balloon latex is better value and also retains flexibility, though latex based products do age.
Priming foam for paint: unnecessary, unless you're using enamel, then building up a flawless finish to apply gloss to is preferable. Rustoleum Stops Rust primer should be fine over the sealant and wet sands nicely.
Hardening foam: rigidity requires a rigid material, so you'll need a coating resin. Lots of resins are designed for smooth coating. Smooth-On Epsilon is the usual standard, though pure epoxy resin - sometimes sold as tabletop epoxy- works just as well. Hardening is very messy though, since you have to let it drip off the sides for a full coat with no meniscus. There are other options for resins too. Smooth-On 65D functions similarly thanks to its slow cure time for rotocasting. Other companies make the same products under different names and may be cheaper, though resin systems are generally somewhat expensive across the board.
Smoothing foam faces: brief passes with a heat gun. It'll become shiny as the cells close.
Smoothing foam joints: 1) make good joints, slowly closed with BARGE contact cement. 2) silicone caulk with blended acrylic paint of the foam's colour (probably black). A few drops of paint should be sufficient, in theory.
Sealing foam for paint: Plasti-Dip or Rustoleum underbody spray both work and retain flexibility. Underbody spray is way cheaper in the US. If you have a good size compressor, balloon latex is better value and also retains flexibility, though latex based products do age.
Priming foam for paint: unnecessary, unless you're using enamel, then building up a flawless finish to apply gloss to is preferable. Rustoleum Stops Rust primer should be fine over the sealant and wet sands nicely.
Hardening foam: rigidity requires a rigid material, so you'll need a coating resin. Lots of resins are designed for smooth coating. Smooth-On Epsilon is the usual standard, though pure epoxy resin - sometimes sold as tabletop epoxy- works just as well. Hardening is very messy though, since you have to let it drip off the sides for a full coat with no meniscus. There are other options for resins too. Smooth-On 65D functions similarly thanks to its slow cure time for rotocasting. Other companies make the same products under different names and may be cheaper, though resin systems are generally somewhat expensive across the board.
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