Large Model Association Forum

I have an airframe that has foam wings which have been glassed. The veneer has lifted in places and I plan to strip the veneer off completely, then re-skin with balsa. The original glue looks like copydex or similar. I'm guessing I need to use the same again for gluing the new skin on. I've never really played with foam wings before so anyone with experience chirp up and tell me how!! My original intention was to simply build new wings out of proper materials but these foam jobsters are actually not bad under the veneer, so I thought I'd try my hand at foam wing ery. The span is about 13ft, in 3 equalish pieces, with a root chord of about 30 inch. Many thanks folks.

Ian.

Hi Ian - its probably industrial Latex (aka Copydex) -If the splits / lifts aren't too bad you can simply add a bit more and roller it down unless its really dried out it may re-stick. you may be able to remove the worst of the old stuff as it should come out like chewing gum! but if its a large area its best to remove it all. I have some if you need any.
cheers Richard

Thanks Richard, in this instance I think it best to remove all the old veneer and reskin in 3/32" balsa or similar, then glass and finish as normal. It has been recommended to use foaming PU as an alternative, do folks think that would stick to the remains of the original Copydex stuff? I doubt the old glue will come off the foam without issues.

Ian.

Ian, use copydex slightly thinned with water and add a small amount of food colouring so you can see where it has been spread. I use a piece of sponge to spread it on. Works every time. Solly

I will throw another one in, mick reeves proskin, Harold dobekin gave us a club lecture on the stuff, which he claims he could supply, He used it on his jets,very impressive, and not at all heavy

When using Copydex I find you get a better job if you coat the foam, and veneer or balsa and then leave overnight to dry completely before rolling the foam wing onto the veneer, I normally start at the trailing edge and roll toward the leading edge. This way there is no moisture left in the adhesive so less chance of the veneer lifting in the future.

Many thanks folks, I let you know how I get on when I do it!

Ian.

Ian, whatever you do, build a simple jig, take the airfoil shape, make a framework with support in 3 places, about an inch wide, this will keep the wing true while the glue dries, Its the usual thing to use the sleeves the wings were cut from, to secure the wood covering, weighted down, without these, just putting the wood on may twist the foam core, its just a filling, there is no strength there

Cor, have i taught the master something