eyal8r
New Member
I have been scrounging for many, many months for the best ways to hard coat foam. I create a lot of 2D and 3D foam props for outdoor use. I've studied a lot of different methods, but haven't quite found the best one to use yet. I know there's A LOT of very knowledgeable members on this site who have many years of experience behind them. I'd love to pick your brains a little on various methods.
Quick background- many of our props are moved throughout the year. They get dinged, dropped, smashed, etc. They also sit outdoors all year long. I make the props out of various materials, depending on the application (wood frame, metal/emt tube, pink or blue foam board, beaded foam, great stuff, polyurethane foam, paper mache, joint compound, plaster, fiberglass, etc). I really would like to find the best way to hard coat these 'sculptures'. The general public usually are not close enough to contact the props, however, at times they might be.
I live in AZ- the summer temps and heat are extreme, but is also exposed to freezing/cold and wet weather throughout the year. Most props that sit outdoors year round end up weathered and destroyed within 1-2 years. The only way around it I've found is Fiberglass- which, is too expensive and time/energy intensive to do.
Here's some of the methods I've found, and some info on them as to why they may or may not work. Please feel free to correct me if I am misguided on some of these things.
Fiberglass
Pros: very hard and good enough for structural use and contact w/ public. Not affected by weather.
Cons: Expensive, very labor intensive when you consider multiple layers, sanding/prepping for paint, etc. May have to prime/coat before if the medium under it will be eaten by the resin.
StyroSpray 1000
Pros: Cheap in comparison. Easy to apply with brush, roller, or spray w/ hopper gun.
Cons: Only works in humid environments- too dry here in AZ to achieve the results they claim- even creating a humid environment doesn't work. Sags on verticals. Peels/warps according to others.
Polyurea/Bed Liner
Pros: Very hard, tough shell. Dries within seconds, completely water tight.
Cons: Expensive equipment (can have outside pros spray it cheaper), must have good experience/training applying it to be done correctly, surface is bumpy due to very fast drying times, must be sanded before it will accept paint. Will have to prime/sand before paint to achieve smooth surface.
Polyurethane Spray Shell/Polyurea/Hybrid
Pros: Fast dry time, hard shell, can be sanded/painted.
Cons: Expensive equipment, must be primed quickly in order to paint afterwords, can get drips/bumps- not always completely smooth.
Plural Component Cartridge Systems (Polyurethane/Polyurea/Hybrid)
Pros: Fairly cheap to get started compared to other systems ($1k for gun, case of material, air masks/suits, mixing nozzles, etc, then another $1500 for air compressor)
Cons: Need much more material than you expect, driving costs up, have to switch out mixing nozzle once you take finger off trigger ($3-5ea), VOCs, etc.
Epoxy
Pros: appears to be industry standard, easily available, fast drying times, hard shell, can be tinted/mixed with fillers, etc. Self-leveling.
Cons: ???
Gel Coat
Pros: ???
Cons: ???
Misc Foam Coats
Pros: Easy to apply (brush/roll, not sure if spray), cheap
Cons: may not hold up to extreme weather, possibly same cons as StyroSpray 1000? Not sure how hard the shell is.
Bondo, Plasters, Joint Compounds, etc
Pros: Easily available, easy to apply via trowel, etc. Can be sanded/painted.
Cons: Cracks (especially when prop is moved, or has a little give as when used over EPS, etc), does not hold up to weather, HEAVY.
Cement/Portland/Dryvit, etc
Pros: cheap, troweled on, dries very hard, holds up to weather, great for permanent installations.
Cons: heavy, cannot be sanded/shaped too easily, will break/crack over EPS and some dings, etc. Not meant to be moved around much.
Again, I'd love to get some insights as to what works, what doesn't, what's the best overall solution. I've yet to try Epoxy- and it seems that many of you use that for the hard shell. How well does it handle weather? Just how hard is that shell? Will it crack if the prop is dropped or tipped over/banged around a little? Do you need fiberglass cloth, or is it just as hard with the Epoxy alone?
I look forward to hearing your input!
Quick background- many of our props are moved throughout the year. They get dinged, dropped, smashed, etc. They also sit outdoors all year long. I make the props out of various materials, depending on the application (wood frame, metal/emt tube, pink or blue foam board, beaded foam, great stuff, polyurethane foam, paper mache, joint compound, plaster, fiberglass, etc). I really would like to find the best way to hard coat these 'sculptures'. The general public usually are not close enough to contact the props, however, at times they might be.
I live in AZ- the summer temps and heat are extreme, but is also exposed to freezing/cold and wet weather throughout the year. Most props that sit outdoors year round end up weathered and destroyed within 1-2 years. The only way around it I've found is Fiberglass- which, is too expensive and time/energy intensive to do.
Here's some of the methods I've found, and some info on them as to why they may or may not work. Please feel free to correct me if I am misguided on some of these things.
Fiberglass
Pros: very hard and good enough for structural use and contact w/ public. Not affected by weather.
Cons: Expensive, very labor intensive when you consider multiple layers, sanding/prepping for paint, etc. May have to prime/coat before if the medium under it will be eaten by the resin.
StyroSpray 1000
Pros: Cheap in comparison. Easy to apply with brush, roller, or spray w/ hopper gun.
Cons: Only works in humid environments- too dry here in AZ to achieve the results they claim- even creating a humid environment doesn't work. Sags on verticals. Peels/warps according to others.
Polyurea/Bed Liner
Pros: Very hard, tough shell. Dries within seconds, completely water tight.
Cons: Expensive equipment (can have outside pros spray it cheaper), must have good experience/training applying it to be done correctly, surface is bumpy due to very fast drying times, must be sanded before it will accept paint. Will have to prime/sand before paint to achieve smooth surface.
Polyurethane Spray Shell/Polyurea/Hybrid
Pros: Fast dry time, hard shell, can be sanded/painted.
Cons: Expensive equipment, must be primed quickly in order to paint afterwords, can get drips/bumps- not always completely smooth.
Plural Component Cartridge Systems (Polyurethane/Polyurea/Hybrid)
Pros: Fairly cheap to get started compared to other systems ($1k for gun, case of material, air masks/suits, mixing nozzles, etc, then another $1500 for air compressor)
Cons: Need much more material than you expect, driving costs up, have to switch out mixing nozzle once you take finger off trigger ($3-5ea), VOCs, etc.
Epoxy
Pros: appears to be industry standard, easily available, fast drying times, hard shell, can be tinted/mixed with fillers, etc. Self-leveling.
Cons: ???
Gel Coat
Pros: ???
Cons: ???
Misc Foam Coats
Pros: Easy to apply (brush/roll, not sure if spray), cheap
Cons: may not hold up to extreme weather, possibly same cons as StyroSpray 1000? Not sure how hard the shell is.
Bondo, Plasters, Joint Compounds, etc
Pros: Easily available, easy to apply via trowel, etc. Can be sanded/painted.
Cons: Cracks (especially when prop is moved, or has a little give as when used over EPS, etc), does not hold up to weather, HEAVY.
Cement/Portland/Dryvit, etc
Pros: cheap, troweled on, dries very hard, holds up to weather, great for permanent installations.
Cons: heavy, cannot be sanded/shaped too easily, will break/crack over EPS and some dings, etc. Not meant to be moved around much.
Again, I'd love to get some insights as to what works, what doesn't, what's the best overall solution. I've yet to try Epoxy- and it seems that many of you use that for the hard shell. How well does it handle weather? Just how hard is that shell? Will it crack if the prop is dropped or tipped over/banged around a little? Do you need fiberglass cloth, or is it just as hard with the Epoxy alone?
I look forward to hearing your input!
