I have too much 30 min. epoxy lying around so that's what I use to fuelproof firewalls AND fuel tank compartments. Brush it on with a disposable brush and heat it up with your heat gun. The heat will thin it out and it will soak in and "case harden" the wood, plus shorten the cure time. I like to slop it on, heat it, then roll the fuse around letting the runny stuff get into all the cracks and crevices. Any excess can be wiped off with your brush.

Don't use CA glue if you're planning on keeping the plane. Guess what the best solvent is for cured CA....NITROMETHANE!! Fuel won't strip it off but will soften it if left on very long.