I built an Elder 40 a couple years ago and also had trouble finding a glue that would hold the open basswood rear structure together. CA wouldn't even begin to hold the sticks together. Epoxie wasn't much better. A tube of "Ambroid" glue came to the rescue. I used ambroid everywhere you were glueing something to the basswood frame on that airplane, including the gusset plates. It has held up well for me with no structural problems in service. Plus I love the smell of Ambroid.