MIMF

I've inherited a 60s Silverstone parlor guitar. The back has begun to separate from the binding on the upper bout, treble side. Brown glue residue from the factory is visible, and it's overlaid with what appears to be PVA from a previous repair attempt. Pretty crusty. Would vinegar be my best bet for cleaning this out before I reglue with Titebond? Thanks.

It looks pretty crunchy to me so using water and/or vinegar will turn it gummy which is not useful in my experience. I would inset coarse sandpaper into the joint then press the joint closed and pull the sandpaper out (aka: flossing the joint). Periodically, turn the sandpaper over to floss the other side of the joint. It shouldn’t take but a couple of minutes to clean up the joint. Just be careful to pull the sandpaper out straight so you don’t round over the edges which would leave a gap after glue up.

Assuming this is a ladder braced guitar, now would be your chance to continue removal of the back and X brace it. I understand this really improves their sound. I'm planning on doing that to a '54 Kay jumbo. Oh, if you do that, make a mold for it first so the back goes on easier.

Thanks Barry, that was my other thought. I’ve flossed the neck joint on a real junker for practice a while back.

Any advice about getting into the transition where the glue still holds?

Carl, that thought occurred to me too. I’ll mull it over while I get a couple other projects checked off.

Good advice Barry. I have an almost survivor that I'll use that treatment on.

For the extreme edges of the break there is not much you can do. They are so tight that if you insert anything the break will probably travel further. So floss where you can and leave the rest. When you go to gluing the joint you can squeeze some glue into the edges by applying a bead of glue over them and then using the pad of your finger like a squeegee to force some into the crack. A thin palette knife is also useful there.

I have found that clean feeler guages work well to force glue into that transition area where it gets really tight. You do need to be careful, as the thinner guages WILL break. Pull them straight out, as opposed to on an angle. I keep a broken one around specifically for this purpose.