Has any one tried Minwax Plolyurethane in a rattle can as a clear coat over other finishes to fuel proof thier plane? I used it on my field box last year with no detectable problems.

The urethane itself will work on almost any type of finish. BUT... you have to be very careful with the carrier and the solvent used in the spray can products. Quite often, either of them will dissolve or wrinkle the base coat. It's always best to make a test piece with any type of finish you are using to test other finishes with. That way the test piece or pieces will display any bad tendencies.

Thanks,

I plan on using thinned latex for the top coat and seal with the poly. I will do some test panels and see. The big think is the fuel proof qualities of the poly in the rattle can.

It's not going to be perfectly clear, it will amber the color a bit, so put it on lightly.
it will really be noticeable over light colors.