I have used Gorilla Glue with great success for gluing balsa skins to foam core wings on SIG King Kobras. I've done it 3 times and if I do it again I will use Gorilla Glue. I've used the foaming kind of GG. As long as you wet down the wood and clamp it after applying the GG, it will work really well and will hold with a vengeance. Check on it while it's drying and wipe off any excess foam that develops.