I've been asked to repair the inlays on a lovely old mandolin that used to belong to my customer's grandfather. My eagle-eyes, however, also spotted this! It was held together with a rusty little wood screw. There isn't great surface-to-surface contact when I flex the joint. Wondering how best to proceed: thinking of maybe cleaning up the sides of the joint and adding a splint to bridge the gap. I guess the alternative is to use some sort of void-filling adhesive? Dowels? Really appreciate any thoughts and inputs!
This is one of very few occasions epoxy glue would work for a quick fix. It's a joint that should not be opened again and epoxy fills out voids nicely. Cleaning up the joint and gluing a wedge with hot hide glue is more work but the better way to do it. I would replace the screw with a wooden dowel.
If this were mine, I might think about using a thin kerf saw and cutting the head off completely, cleaning up the joint and then gluing it back together. If it's hide glue the joint might come apart with care and hot water. I'd also think about adding some splines on the fingerboard side for a bit of reinforcement.
Maybe I should have made a new post, but this is similar to yours Keith.
I usually don't work on mandolins, let alone an old bowl back style. I'm not versed on their construction other than now reading a little about Italian and German style joints. I rescued a simple bowl back, a Goodwill special, and the neck/body joint was a glued up mess. The 10th fret was missing and I thought some one had razor sawed the neck off to attempt a reset maybe. Then re-glued the joint a little off. But after slowly working on the added glue with hot water and a hot separating blade I found a nail centered in the neck. This nail came completely through the neck block and into the neck. And with a mirror you could see the nail was under the paper lining the bowl was covered with. It took awhile to work the neck off the nail. It had to have been done in construction I would think.
The original neck/body joint failed or was broken somehow. But once apart it was very clean, only breakage was to the bottom of the fingerboard. It had originally been assembled with hide glue.
Was this a common style on low end mandolins? Made the neck reset easy. Last interesting note, this thing has bone tuner buttons that jumped out and caught my eyes when I saw it. Now to research top crack repair and bowl segment joint separation. May just become playable down the line.
I now return this post to Keith's topic.