I've covered lots of planes with film and have had no problems, except when I get to the firewall. If I leave an edge at the side of the firewall fuel eventually seeps through. If I cover the firewall too, then the film gets baggy and fuel gets under it from the engine mount bolts. If I coat the firewall with epoxy then the 'kote wont stick to it...

Is there an obvious or not so obvious solution that I am missing?

You could try painting the firewall with a couple of coats of epoxy thinned with alcohol after you have covered the model so that the epoxy goes over the small amount of covering that goes round the corners to the bulkhead and seals the edge in the process.

It works for me!

-David C.

I paint my fire walls with the same color dope as the covering as for the edges of the film i use CA to hold them in place

Yes, there is a solution. It's called Balsarite. It's available at Tower and many other places. I use it on all the balsa surfaces to help the covering stick better. Since it's fuel proof, I also use it in the engine and fuel tank areas as well as places where the covering ends, such as around the wing saddle. I usually do 3 or 4 coats in the engine and fuel tank areas.

Extend the fuse covering so that about 1/8 to 1/4 inch folds over the firewall. Then seal the firewall area good with several coats of dope, Balsarite, or epoxy.

i just use epoxy, and brush it on

everyone i know uses this method..weve never had issues w. this method[8D]

I use a 50/50 mix of 15 minute epoxy and denatured alcohol. It works great. Around the edges is where it will seep through about any sealer you use eventually. To cure this, around the edges you can lay in some really light fiberglass cloth and just paint it in with the diluted epoxy mix. You dont have to glass the entire engine compartment, just cut strips about 1" wide and as long as the corner and lap it about 1/2" on each side. It wont ever leak and it weighs virtually nothing.