The best way to find out is to cover a piece of scrap balsa with the film and apply a few surplus decals. The Brodak kits I've seen and built, repeat the Brodak name on the decal sheet many times for that purpose. Several test panels can be made to try different types of clear coats. Taking the "sheen" off the film with very fine sandpaper (1000 grit) or steel wool might help flow out and adhesion.
Spray the clear you intend to use over the decal and the film and see what happens. If you spray a wet coat of clear dope the decal will likely dissolve! "Dusting on" dry coats, followed by increasingly wetter coats, lessens the chance of thinner attacking the decal. The photo (if it uploads) is a Brodak Flite Streak Trainer I built years ago to (among other things) try out Brodak Dope (in the past I used Sig and they have differences). There is no film on it, it's all dope, but the decal is a water transfer I fuel proofed by spraying clear dope over it. I dusted on 3 dry coats and followed up with 2 heavier wet coats. There was too much thinner in the last coat and it sagged a little in places, but you can't tell from the photo. When dry, the decal was a permanent part of the finish and as fuel proof as the rest of the plane.
I don't think dope would stick very well to film. Clear Lustrekote in a spray can is a better choice. I've read where Rustoleum and Krylon have been used. Clear Rustoleum might have a tendency to yellow. Krylon will probably be the least likely to curdle the decal, but may not be as fuel proof as you want. Spray cans make it hard to control the volume of material applied. With LustreKote, it looks like a thick coat is being dumped on, but it dries thin, hard and fuel proof.
To check the fuel proof qualities of the well dried clear coat, put a little fuel in an atomizer bottle and spray it on the test panel (outdoors with no spark or flame nearby!). Let the methanol and nitro dry, then wipe off the oil residue with a paper towel. If the clear coat is soft or tacky, it would not be my choice for the model.
Here is an "off the wall" idea: If the decal(s) are of modest size, why not cover them with clear film. Press it over the decal and work out all the air bubbles, then just heat seal it around the edges. Test it first, just like the paints. Even without heat, the film adhesive (or any residual solvents in it) might attack the decal. It might look OK at room conditions, but things could change outdoors under a hot sun. Water transfer decals (at least the ones I've used) have very little solvent resistance.
Regards, EWP
Topic: Clear over kolar kote (Read 854 times)
