Covering Foam Wings...

I have a styrofoam wing to cover. I was told that Ultracote works well for this task and I got some. Aside from making sure the surface is clean and even, what sort of surface prep is necessary? DO I need to spary it with 3M 77 stuff, or just start in? Any gotchas or tips? I've never covered foam before, only open wood structures, so this is new.

Kim Elmore

You're just going to put the plastic over the raw foam wing?

Most foam wings are planked with balsa sheeting, which adds tremendously to their strength. Some RC guys even use obechi plywood for that.

I know that Tom Dixon has a technique for faux rib caps on foam wings, but he still planks the leading and trailing edges..

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"My wife and I were happy for twenty years. Then we met." -Rodney Dangerfield

I've seen combat guys do this, and it's done with RC combat wings. I've seen the decking used in most cases, too, but this is a throw-it-together-and-fly-it sort of deal, along the lines of a Ukie (Ukey?). Covering it will add to the strength and protect the wood spars. I've heard of covering it with plain paper and latex paint, but I want something a bit more durable.

I've done a couple hundred airplanes in Solarfilm. It's pretty easy. Just iron it on. You might want to put some polyurethane paint on the seams; the adhesive is not fuel proof. Solarfilm is sold under various names in the US. Flite Kote is one of them.

Solarfilm varies a lot in weight with color. The fluorescent colors are very heavy. White is heavy. Red and the translucent colors are light. Clear Solarfilm exists in England, but I haven't seen it here.

Local cheapskates have successfully covered foam with plastic film from flower shops, stuck on with 3M77. Another cheap, strong covering is FasCal, but it is a lot harder to work with on foam.

I have a foam winged Mustang OS LA 15 size and its covered with Ultra Cote with two coats of Elmers Glue to add stifness to the wing. It works ok but easily dings, Phil of Core House uses silkspan over his wings put on with Elmers. I tried this and its much better and does'nt ding as easily. Speak to Jim Pearson' ask what he uses on the UKEY series as now the wings are not as easily Dinged. SEE YA NEAL:)

Kim,
The reason Ultracoat is used on foam is because the film bonds at
a lower temp than monocote. Some of the carrier guys use this on
foam wings without any other covering (Wing is designed for this
application) for weight reasons. It works fine, but you'll never
get front row appearance points. Just be carefull not to use to
much heat when applying film or else you run the risk of melting
the foam. Good luck!

Ah! So I see that the hearsay isn't all wrong. Since I have the Ultracote, and I don't have any silkspan (shame on me!), I'll try straight Ultracote first. Appearance points mean zilch for this airplane! I have another wing to cover, and I may try silkspan on it followed by Ultracote. The silkspan with Elmer's/Titebond glue sounds terribly messy and a great candidate for weight gain, so judicious use of a credit card scraper is obviously needed, from what I've read. How do I avoid warped wings as the silkspan dries and shrinks? Or, do I simply not worry, apply the Ultracote and then pull out any warps?

One small touch - - You might consider adding a strip of 1" filament strapping tape spanwise at the high point of the chord (top and bottom). This will make the wing very much stiffer spanwise.

I hope this is a wing core with slots top and bottom for spars. If it is, it is more or less standard combat style and you can cover directly over the foam with Ultracote, or the SLC film I have.

take a look at http://home.earthlink.net/~philcartier and click on the true beam wings link. There is a complete covering sequence for making a very nice looking finish on foam wings. The only change I recommend now is to cover the wing with the covering first and then the silkspan(to give a base for sanding and painting). Other folks are simply covering with film, and then priming, sanding , and painting. It's lighter, but a layer of silkspan helps prevent dings.

Here are a couple other options.

1.5 mil laminating film, available at your local Kinko's, or from usi-laminate.com. Opti-clear is good.

Packing tape. The RC combat guys like this stuff, as do the flying wing (Zagi) people. You can get it in colors, too, if you look around.

I guess it depends on how pretty you want this thing to look.

I have mix Elmers with water 50/50 and applied it to the wing with a foam brush. Spray each panel of silkspan with water and blot the excess water off. I lay the silkspan on a towel for this. Then apply the covering to the wing panel. Apply it so that the covering panels will overlap each other around the leading edge. Tear the edge of the covering wrapping around the leading edge. It blends in much nicer. Its really not as messy as you might think and tightens nicely. Use a foam brush to apply water base fuel proofer. Hope this helps. Mike

LAST EDITED ON Nov-06-04 AT 01:02 AM (CDT)
 
Yeah, forgot to mention the old paper covering trick. Works pretty well, and the result is a much stiffer wing. Instead of white glue, I use wallpaper paste with some white glue mixed in. Incidentally, Phil's big Giles stunter uses silkspan on the wings, except I think he used Polycrylic to apply it.