I use SIG clear buterate dope ,to fuel proof my stuff ,since the late 1950's
I use to do silk and dope to cover my wing open bays ,back in the day
It dries super fast ,and is lighter than epoxy ,both of which are important to me ,to keep my airframes as light as possible
In a pinch ,you can paint and it will be dry by the time you get to the field
Good Glo fuel protection ,up to 15 % nitro
I fly RC Glo engines for 23 years ,no mushie balsa for me. LOL