ORIGINAL: pjwright
I'll give the clear coat a try ... usually I seal Monokote edges with clear (laquer) nailpolish. I also go over the entire plane with Meguiar's 'Deep Crystal' automotive polish, which not only gives a fanastic sheen to the plastic film, but affords
some protection from exhaust residue.
Cheers!
PJ
Nailpolish is OK, but a bit localized. You typically don't get the entire plane with it.
Automotive polish makes the finish look good, but does not really seal the edges all around.
You can use something like Krylon clear coat, or anything else that might be fuel proof.
I'd recommend that you do this before your first flight. It makes a huge difference to how the covering holds up.