I used to use the Poliurethane glue, Elmer's Probond, very good, actually the best method I have ever used, I tried white glue(aliphatic resin), epoxy and sorghum, but nothing is better than the polyurethane in my opinion..

I used to apply it to the wood and spread it with a piece of scrap balsa plank , it has to be very thin, then spray water on the foam evenly, used a piece of wood or granite at least the size of the wing, and for the weights I used a camping cooler filled with water.

Let it set overnight or 24Hrs.