BEFORE YOU USE THE EPOXY, "dry" fit the joiner(s) and wing halfs to gether FIRST. MOST ARFs have no problems, however, on occasion, I have seen some where the joiners didn't fit properly.

What you want is a SNUG fit, not a tight fit, with each joiner half in the wing and you also need to make sure the wing halfs WITH THE JOINER IN PLACE, will fit flush with each other.

If there is a problem you want to find out BEFORE you put the epoxy to it.

As for epoxy, just about any type of 30 minute (or longer) epoxy will work. I have occasionally used the stuff in the 2 tubes that you can get at Ace, True Value, Wal-Mart, etc.