ORIGINAL: lrglnman
As you can see in the pics is the results of gorilla glue. I guess if I were to do it again I would use a lite coat of epoxy to sheet the wings . look in pic 3 and you will see what I mean keep and eagel eye on it until it sets up . the foaming action of gorilla glue will move the parts around as it foams. I had 30 lbs od lead weight and it still moved and I missed it.
If you are sheeting with weight you need to use minimum 300-400lbs to get a decent bond, especially with polyurethane glues. I know this sounds like a lot, but pulling even just 5" of vacuum (just under 2.5psi) will put well over 1000lbs of force on one wing panel of the size you are working with. Without crushing the foam or causing any other issues. The only issue with this much weight is that your table has to be strong enough to carry the weight without sagging. Better options than weight are vacuum (as mentioned) or using a press to apply even force.
The best page I have ever seen on sheeting foam cores:
http://www.mackrc.net/patternwings2/index.htm
Terry Brox is a master at it and his workmanship is superlative.
Mark