elenasgrumpy,
I'd like to add something about your question.

Any paint or glue that's fuel proof works to fuel proof engine compartments. Just as RCKen said.

But there is reason to the madness that goes a bit deeper and that is....

If you have any concerns about the strength of an area that needs fuel proofing, glues add measurably more strength than paint. So if you have an ARF with a firewall that looks a bit suspect to you concerning it's glue joints or the quality of it's wood, glue is a good choice to do two tasks at once. And obviously, epoxy is one heck of a glue.

But if the area you want to fuel proof obviously doesn't need strengthening, paint is lots less trouble. Or if you're building a model and you need to keep the weight as light as possible, paint is usually lighter, although that's not always a given. However, one coat of paint very often doesn't do a very good fuelproofing job. Depends on the paint. Aerogloss or Sig dopes don't do a very good job with just one coat. And they don't do a very good job of lasting right where they're needed most, at the joints. And they won't cover well over some of the hotglues the ARF factories are using. You really need to make doubly sure to get a good wetting with paint around the joints and around those rubbery glues. Make sure you look closely after the paint has dried to see if you might not need another coat. and..... after that coat.....

And if you have a hard to get at area, epoxy is a pain to try to apply inside small spaces and doubly hard to apply only as much as you need. It's also really hard to insure total coverage if you can't see everywhere it's going. However, there is a trick that's helpful. Leather work requires dying sometimes. And that craft has neat "wool daubers" that're dead cheap and do an excellent application job with epoxy in hard to reach places. They have a blob of wool at the end of a twisted wire handle. You can bend that handle to make the blob go wherever you need it to go. If the handle isn't long enough, twist another handle together with that, and hold one of the blobs, and you got a twice-as-long handle.

So the choice is like a lot of things we do in this hobby, it's not a simple, single reason choice.

Hey, satisfaction guaranteed..... if you're not satisfied, there is no additional charge.

(btw, I maidened my WM.46 ULTIMATE an hour or so ago!!! BIG GRIN)