MIMF

I'm working on restoring this old SuperTone parlor guitar and encountered this nasty old black glue that someone in the past used to try and repair a side split.

It doesnt seem to dissolve with anything I've thrown at it yet... water, alcohol, lacquer thinner....

its really brittle and a bit 'crystal' like.

any ideas on removing it without just scraping with a razor or similar?

The stripe shape suggests that this is residue from tape. Try mineral spirits or, even better, Goo Gone (this is good stuff).

I wondered about that (tape)...... and thought maybe they globbed on the black glue and taped over it.... because it definitely has a cross-hatch pattern like tape was over it. inside the body, you can see a lot of squeeze out thru the split that suggest there might be more glue there than could come from tape residue.

I'll sure try the mineral spirits though.

Try a little vinegar also. It will loosen PVA type glues.

Looks like it might be resourcinol or something similiar. Weldwood used to make a furniture glue that looked like that. I suspect the glue was slopped on and duct tape was used to hold the split closed.

Is the crack actually glued? Is there glue squeeze-out on the inside? If not it may not have been glued, but only taped. It looks like tape residue to me. Mineral spirits or naptha would be my first solvent to try.

Looks like tape to me, too. Old tape can be hard, very hard, to remove. You might have to physically work it(IE: scrape) in order to gain access to the actual adhesive layer.

Ron Belanger wrote:...Is there glue squeeze-out on the inside? ...

Wouldn't that be glue "squeeze-in"?