My guess (being a kiwi) is they would have rang the local hardware store and said " what have you got that will glue alloy sheet"
Don't forget Bruce had an engineering degree so was streets ahead of most of us to start with. I'm picking everything would have been backed up by calculations and I would venture that he would be more likely to be quizzing someone in the aviation industry rather than his local hardware store.
Carey Taylor was heavily involved in the McLaren CanAm program. He would know for sure how they were done in the day. He's still around here in Chch. I'm sure he would be very helpful if you were to contact him.