What I am looking for is an easier alternative to mixing epoxy resins for attaching glass to foam and still getting some strength. If it works as a filler with a couple coats is even better.

I have been using MinWax polyurethane for several years now to fuel proof my firewalls and tank compartments. I never use epoxy anymore for fuel proofing. Two coats and the surface is good to go. I have not been happy with the spray cans and now apply from the can with a foam brush. The final coat must be lightly sanded. I've also applied silkspan and light fiberglass over sheeted balsa with good results. I used it to fuel proof open bays of Koveral and was disappointed. But I think the fault was mine. I didn't mix a filler such as talc, corn starch, or micro baloons. I think with a little filler, the results would have been very good.

Something I found out....the poly-urethane(water based) is NOT fuel proof...but the oil based urethane is somewhat fuel proof. About the only paint that is totally fuel is automotive 2 part paint such as PPG. If anyone has any knowledge of spray paint that you can buy at home improvement type places post it here.

Boss248 - I've used poly on several planes and not had a problem with it. It is not 100% fuel proof, but raw fuel has to sit on it for a while before having any effect. Hot exhaust doesn't touch it. Just don't dump raw fuel on your plane and leave it there and you won't have any problems. I've never had any poly on my planes become damaged from fuel. The only damage is directly under my fuel jug in my flight box.

- Paul

Paul...are you talking about water based polyurethane?? I guess your'e right that under normal use the poly is somewhat fuel proof...maybe my test's were a bit to aggresive...I just eye dropped some 15% Omega on it and it went soft fast. I am just gun shy about painting a complete plane only to realize that it is dripping off after a flight.

I'm talking about solvent base minwax clear. I'm doing my whole plane in it - the one with all the inlays and stuff.

http://www.rcuniverse.com/forum/Meet...1363216/tm.htm

Scroll to the bottom of the thread to see how it looks.

I'm new to RC and am going to reinforce the wing center section on a couple of wings. Can fiberglass be applied over covering?

No. If you're talking about an ARF then cut away the covering before puting on the fiberglass.

[quote]ORIGINAL: CafeenMan

Forgot to mention that there is no sheeting on one, a Robin Hood 99. The plans show two center ribs which have been cut to insert a single World aileron servo. The single servo will be removed and replaced with 110 oz-in servos for the ailerons on each wing half.