Last week I picked up a late ‘70s Ibanez 518, a nice little solid wood A-style, from Goodwill for under $100 with the original (and nearly mint) hard case. In the photos from the listing, I could see that the top of the back had come loose, but for what I paid for the mandolin, that wasn’t too worrisome. Of course, caveat emptor when buying from Goodwill: they neglected to mention that the rest of the back had been sloppily glued back on by what appears to be Elmer’s glue. I couldn’t see that in the photos, and the description mentioned a reglue but I assumed they were talking about the loose area. Ah well, it’s a beautiful mandolin!
Here’s the bottom with the mystery glue. It might be hard to distinguish from the wood, but that’s because everything there is white glue. There were no close ups of this seam in the listing. Sigh.
It was clear that the back had come mostly loose sometime in the past, prompting the mystery glue job. The trouble was, the back was glued on after the sides had come out of shape, so the sides stick out at several points around the mandolin.
I set about to remove the old glue, so I could get the sides back into shape and get the back to fit again. the treble side of the mandolin is still glued up, and I am trying to keep it that way. I figure it will be easier to get the sides back in shape if I have at least one side already attached properly. If I gently put pressure at the tailpiece, I can move the bass side in and the back lines up all the way around. This leads me to believe that I can make a jig that will hole the sides in place while I glue the mandolin up. I picture something like a jig for building a mandolin and holding the sides in place while you glue the back on, shaped like the back so that the sides will line up. I’d use hooks attached around the jig to do the string clamping trick to hold the back down. But I’m getting ahead of myself!
I’m slowly removing all the glue. I suspect it’s Elmer’s - it is very white, and it softens in vinegar. I don’t really want to use vinegar to remove it because (as I’ve read here) now instead of glue in the wood I have an acid. So it seems like another problem to deal with. Gentle heat from a heat gun and scraping with a small bookbinding palette seems to be the best method of removing all the glue. I’m going slow and trying to avoid heating the polyurethane finish. After a few days or working here and there, I’m about half way around the opening.
Here’s a shot of the inside where you can see the glue removal.
The mandolin came from central Florida, so high humidity and hot. Maybe that contributed to the glue failure? It’s now in Michigan, so high humidity in the summer and warm, and freezing and what feels like negative humidity in the winter.
So I’m trying to figure out a few things, and have a few questions. A few things to start with:
First, I have built several instruments, so I’m comfortable working on this myself and seeing it as a learning experience. I only say that because the first post to any question is always “take it to a professional.” If this were a nicer mandolin, I would do that in a second. But I have less than $100 invested in this non-historically significant instrument, and I’m okay if it becomes a repair lesson!
1. I can scrape the glue off down to wood, but won’t there still be glue in the pores? Does that affect the glue I choose to use for the repair? Can I get it out?
2. Should I glue this up with HHG? My wife is a book binder and we have a HHG pot in the bindery, about 15 feet from where I’m working on this mandolin. I also have original Titebond, but I am not looking forward to scraping white glue off in this comes loose again.
3. Is there a better/different way to realign the back and sides when this happens? I couldn’t find a lot on the forum on what to do when the sides don’t line up. Just a lot of warnings not to let it happen.
Thanks again for the great advice and tips that have been put here over the years. Really helpful to get me started.
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