Finishing styrofoam

I would like to experiment with styrofoam for wings and
airboat hulls. I've made a hot wire for cutting - it's an
interesting process. My question is about finishing. Most
finishes attack the foam. Are there any finishes I can use,
or is there a type of foam that is impervious to solvent
based finishes? Any hints or references would be
appreciated.
Starting back in modeling after 40+ years,
Randy
Reply to
BCRandy
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The foamies can be covered with latex acrylics which are very inexpensive. Spraying with Krylon clear give a protective finish if you clean up the plane right after using it. My buddy uses it on his foamy's and his are all electric and does not worry about fuel attacking his finish. He swears by Apple Barrell latex acrylics sold by Walmart for as little as 80cents a bottle. It can be thinned with alcohol and airbrushed. Great for camoflage techniques. I only started to experiment with different finishes and have asked some questions on the clear acrylics that can be sprayed with airbrushes. There is plenty of information out there and by simply asking you will be many different replies depending upon Nitro or Electric. Doc Ferguson
Reply to
Doc Ferguson
Another option is to apply light-weight glass cloth and paint down with a water-based polyurethane.
Reply to
Poxy
Many yearsago Midwest Models had some stuff they sold that was made to put on raw styrofoam. You brushed it on, let it dry, sanded it lightly to smooth it and they you could put any paint on top of it. It filled the small spaces in between the expanded beads in the foam. Worked great! Naturally, no longer available. Anybody know what it is? It was probably some product they bought in bulk and repackaged... Wish I still could get it. Frank Schwartz
Reply to
Frank Schwartz
I'd bet you could do this with "lightweight spackling" from your local hardware store. It's not usually that thin, but it's water based, and I've certainly gotten it runny enough to brush (unintentionally!).
In fact, that's given me an idea for how to use it for some particular model railroading applications...
Reply to
Joe Ellis
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A friend of mine finished a Midwest foam plane with the stuff that Frank is referring to. This was in the late Seventies.
I was going to say too that it looked like the light weight spackling that is available today.
Remember, it isn't what you put on that counts. It's how much you sand off.
Ed Cregger
Reply to
Ed Cregger
Gentlemen: It (the Midwest product) was definitely not spackling compund. It brushed on like some sort of paint and dried to a hard finish that as said before, accepted any kind of paint. Frank Schwartz
Reply to
Frank Schwartz
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I agree with you Frank. But I think that some of the light weight spackling compounds that are out today could be used as a substitute. Maybe mixing in some easy to sand microballoons (phenolic) of some sort would help.
The old Midwest product was perfect for the job and may be tough to duplicate, but it might be worth a try on some scrap pieces of foam.
While my friend's model did look good, it came out too heavy. I would have just put some low heat plastic film covering on it and called it a day.
Remember the Byron foam kits that some folks used to fiberglass? I've thought about using 1/2 fiberglass cloth and the water based polyurethane that is out today. At least the water won't warp the foam.
Ed Cregger
Reply to
Ed Cregger
I am currently re-finishing some styrofoam floats with fiberglass and water based polyU. seems to be ok. Just have to get the guts to spray paint it now. mk
Reply to
Storm's Hamilton
In the "old" days, I used to mix talcum powder with clear dope to make a filler that worked very well. I will be giving a talc mixed in water based polyurethane a try. I am also going to try using silk cloth in place of fiberglass, since strength is not a major concern. I'll let you all know how it works out.
Randy
Reply to
BCRandy
plain old spackle works well as a filler, and tissue (or brown paper, or silk, or glass cloth) and WBPU (or acrylic) varnish makes a good surface over all to take paint.
Reply to
The Natural Philosopher
That was called Styromate, had its own thinner. I think I have a jar of it. I think they stopped making it because, although it gave a good finish, I think it made the styrofoam brittle. Earle
Reply to
earle

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