Both great ideas, first I need to fix my Storch....Had a bad crash yesterday involving trees and high tension power lines...anyway, the empennage is almost severed from the fuselage. I'm devastated...I think I can fix with some hot glue and extra foam board (the W&B will be crazy though), possibly make a new fuselage...the wing survived however...I'm ok...physically...
Sorry to hear you crashed. I did that once with a balsa park flyer... not very pretty. One tip on your repair, hot glue is really heavy so go light on it. It is much better to replace sections with new material. My suggestion would be to use hot glue to tack the broken pieces in place. You can also use tape, skewer sticks, and pins to hold pieces in place. Once the piece is tacked on, make a splice joint to strengthen it.
First, pick the largest flat surface that makes up the joint. Cut off the exterior paper and core foam to make a slot on either side of the break. Use spray adhesive to glue some lightweight printer paper on the inside paper wall that remains. This will act as a doubler to reinforce the skin. If you have access to both sides of the foam, put this doubler on the back side of the paper before cutting a slot.
Next cut a piece of foam board that is about a half inch larger then the slot you cut. Remove one side of the paper and cut the foam back to the size and shape of the slot. You should now have a slot cut in the surface with only the back side paper and doubler patch remaining. You should also have a piece of foam just big enough to go in the slot with a border of about a half inch of extra paper around the edges. Use spray adhesive or gorilla glue to glue this foam patch in the slot.
Repeat these steps for all major flat surfaces requiring repair. Once at least 3 sides are patched and cured, remove the tape, hot glue, and other stiffeners and repeat the process for the parts of the joint that were hot glued or inaccessible with the tape on.
If the glue was applied correctly, this process should leave you with an air frame that is actually stronger then before the crash and only marginally heavier. Sorry for the long description. I would have made a video, but I don't have any foam board right now to demonstrate with and my hobby budget is tied up with other projects.
You can always just hot glue it back in place and deal with the weight if you need to be back up in the air immediately. I prefer to add as little weight as possible.