Thanks Jetts, I'll give it a shot. I'm not exactly sure how I'll get that balsa out, but we'll see how it goes. The Armor All is an interesting touch...I'll run it by my instructor.

As far as foam...I'm had a hard time locating a source for a decent foam. I found some (possibly latex) foam at one hobby shop, but an 8"x10"x.5" (approx.) sheet of the stuff runs like 4 or 5 bucks. I found some window a/c sealing foam which is about a 2" square and maybe 3' long, for less than 3 bucks. Why would the kind of foam matter? Does this stuff react poorly with fuel or something?