I am currently restoring a banjo ukulele, actually an eight string mandolin type with a spun over rim. Bear in mind this is a bottom end, British made banjo of no great value. The neck and peg head are fine. They just need a good clean. The scarf joint on the ash wrap around rim had come unstuck due to damp in the past I suspect. After much thought and several attempts with different clamping arrangements I decided the only way to rectify this was to take the plunge and “unspin” the rim.
After a lot of careful prising metal and wood separated. I believe the metal is nickel plated zinc, not brass, anyway it was fairly soft. Scarf joint reglued the woodwork is literally in much better shape.
My question to the Hangout is – Is there any advantage in using an adhesive between the metal and wood when I put the outer metal skin back?
My concerns are differential expansion, though hopefully the instrument won’t be subject to extremes of temperature and acoustically is the rim better with and air gap, albeit small or consolidated with adhesive? This would make it more rigid.
I plan to push the spun over edge back in place by hand with a suitably shaped hardwood or may be nylon block. Many thanks, Richard