I have used hot glue for RC stuff, and a coroplast 1/2a basher. I have glued servos into foam, among other things. It gets heavier than epoxy really quick because it is so hard to spread it thin over large areas. There is no way to make hot glue lighter while epoxy can have microballons, balsa dust, or other lightweight fillers mixed into it.
The basher is a man-win wing from the Balsa Beavers website. I was having problems with snow, ice, and mud packing into the flutes so after cleaning I filled the ends with hot glue. Due to the number of awful landings that filled these flutes the holes in the wing for the motor mount gored out so I filled these with hot glue and redrilled. I also went to pin hinges instead of a cut flute since I like having "down".
This basher has been bashed much harder since the rebuild with pilots as young as 6 driving it straight into the dirt with no further damage. It does not fly quite as nice with the extra weight, but is still capable of insides, outsides, inverted and rather lazy 8's. The baby "stunt" bee on it only has 10 level laps in the tank though.
I am building a new one to give to my nephews, and will use Gorilla Tape on the ends (The stuff is pretty awesome). I will still use hot glue reinforcements, and if I use pin hinges, I will hot glue those too. This one is getting an old Golden Bee.
Phil
I asked and Bernie delivered.
http://coxengines.ca/aluminum-fuel-tank-for-cox-049-engine-stunt-version-silver-5cc.html