I use gorilla glue and vacum bag the parts. You have to have everything ready to go, not much time with the stuff before it starts setting. On large parts like the wings, I wait till there is a cooler day than normal and low humidity, I also keep the glue in the house, keeping it cool gives me a few extra minutes.
We just did two sets of wings using gorilla glue, We lay carbon tow over the foam. Tried something a little different this time. While Kevin was prepping the wing skins I ran a bead of gorilla glue down the carbon tow then I took a squeegee and ran the glue into the tow. It penetrated the tow so it has good adhesion to the foam and sheeting. We laid the wing skins over the foam put it back in the shuck and bagged the wings.
We just did some testing with gorilla glue and epoxy ( west systems) I wanted to see how each bonded using carbon tow and another material which one of the guys have tried and that was the fiberglass tape they use in sheet rocking homes. The great thing with the tape is its self bonding when you lay it down. This was just a bonding test, no vacuum or weight, straight out gluing to a bare piece of foam block. No water on the gorilla glue.
Anyhow we tested both materials. We did a pull test using both materials and both glues; On the carbon tow both the gorilla glue and epoxy bonded well but when we pulled on the tow more beads of foam came up with the gorilla glue than the west systems. The epoxy did pull beads of foam but not as much as the gorilla glue. I would still be happy with epoxy.
On the fiberglass tape did not bond as well using epoxy. when we pulled it off the tape was still very flexible, With the gorilla glue it bonded slightly better and the gorilla glue expanded into the weave more making it stiffer. Using the tape did not bond as well as the carbon tow for either glue.
This was just a test to make us feel better and choose a bonding method. I think either glue is a good choice. I think the advantage of epoxy is it give you greater working time.
Al