hello guy's im in need of a bit of help if pos.
i just started rebuilding my foam jet after a few bump and scrapes.so i would like to know.im using z-poxy finishing resin and glass cloth can i use it over the paint or will i need to take it back to the foam or will it still set ok on the painted foam.
iv never use'd finishing resin before so any other tip would be good

thanks very much
ian

i would think you can go straight over the paint, epoxy should cure no matter what (unless floating in vinegar).

I'd still to a small test first to check you don't contaminate the epoxy.

ok thank u mate ill give it a try on somewhere on the plane

thank u

Ian, glass and resin over a foam RTF to effect a repair is going to add a considerable amount of weight that was not part of the equation when the model was first flown. Expect a lot of the nicer low speed handling to become rather more demanding. And this is compounded by the fact that the model will almost certainly require moving the battery pack as far forward as possible and STILL needing to add a considerable lump of nose weight to get the balance point in the right spot. Because of this you may find that you're better off to simply repair any breaks, reinforce the broken area with some manner of inletted carbon rod or strip and do a quick and dirty paint repair.

It doesn't have to add excessive weight if its done correctly and rather than using S glass you can use either carbon or glass tissue you don't need much resin at all to wet it out and one small brush full of resin will spread over a few inches square , trick is 1. Dont rush it 2. app a light dust coat of 3M 77 to the tissue 3. Apply the tissue to damaged area 4. Apply the epoxy as sparingly as you can and finally spread with a good old bank card wiping excess epoxy off with a rag after each pass. FWIW
P.S. Always wear latex gloves when handling resins

Originally Posted by BMatthews

Ian, glass and resin over a foam RTF to effect a repair is going to add a considerable amount of weight that was not part of the equation when the model was first flown. Expect a lot of the nicer low speed handling to become rather more demanding. And this is compounded by the fact that the model will almost certainly require moving the battery pack as far forward as possible and STILL needing to add a considerable lump of nose weight to get the balance point in the right spot. Because of this you may find that you're better off to simply repair any breaks, reinforce the broken area with some manner of inletted carbon rod or strip and do a quick and dirty paint repair.

Thanks mate it has brakes to it it just hanger rash.it's on a fly fly bae hawk well overpower'd any way

Originally Posted by steve wenban

It doesn't have to add excessive weight if its done correctly and rather than using S glass you can use either carbon or glass tissue you don't need much resin at all to wet it out and one small brush full of resin will spread over a few inches square , trick is 1. Dont rush it 2. app a light dust coat of 3M 77 to the tissue 3. Apply the tissue to damaged area 4. Apply the epoxy as sparingly as you can and finally spread with a good old bank card wiping excess epoxy off with a rag after each pass. FWIW
P.S. Always wear latex gloves when handling resins

thank u very much iv herd about the bank card thing iv just found a few so ill use them.and im using 18 gram fiberglass cloth
ill post some photos when it's finsh'd (if it work's)lol

thanks for your help mate
ian

FWIW, I covered my 3rd GWS formosa with 1/2 cloth and 1 coat of WBPU to help protect the foam as the other 2 I had earlier were lost to the foam wearing out from handling and such. It's basically picnic cooler foam, and after about 2 or 3 years it started loosing it's beads where I would pick it up.
Anywho I gained slightly less than an ounce with this process. And compared to the other 2 this one flies noticeably heavier. With the other 2 I could drag it across the sky inverted inches from the ground rather nose high. With this one I need to keep the speed up a bit more, and no where near as nose high. Same with landings. The things still flies GREAT and if I didn't fly the other 2 it would have been a moot point, but even less than an ounce made a difference. It was less than an ounce, but we're talking about a 16 ounce airplane...
Also... this "version" is still going strong after about 3 or 4 years... No sign of wear.