Loose top braces on a hunk of junk mandolin

[Johannes Eriksson]

Hi all, I've only dabbled a little bit in instrument repair, stuck a few guitar bridges back with hide glue, made a diddley bow, converted an old kids guitar into an electric mandola, that kind of thing, and I'd love to be able to play some blues on the old mandolin that was forced upon my mother in school...

I made a couple of tuner buttons for this mandolin out of an old chopping board (yes, that's the level we're at) but unfortunately I also noticed that the top was sagging a bit on one side and upon inspection both top braces (which run perpendicular to the fretboard if that makes sense).

Now I've been thinking that since getting to the brace that is further from the sound hole would be pretty tricky to get to and also seems to need cleanup of old glue, I might be best off taking off the back. There is no back binding or back kerfing at all so it should hopefully not be too tricky a job, although putting it back might be trickier? It doesn't seem worth using hide glue since it looks like it's been built with white PVA glue to being with, I was thinking to use yellow glue (Titebond original) purely on the basis that it was used for a top brace repair in a frets.com article...

Does taking the back off seem like the best thing to do or is there a way I could do it via the sound hole?

Thanks!

Johannes

The old gal:

No binding, very thin finish that's really scuffed around the edges anyway (also chopping board tuner buttons top and bottom right):

No back kerfing, white glue?:

First brace, very loose:

Second brace, also loose behind all that glue:

[Ned Knepp]

Hi Johannes.  Taking the back off is probably the easy way to get to the braces but it also makes the whole repair much more complex. That said, as an amateur with big hands and big forearms mixed with no deadlines, I have used this approach a lot. 

 I suggest that you consider how you are going to put it all back together before you starting taking it apart. The first time I did this I was very surprised to find that the back didn't want to line up properly when I tried to put it back on... 2 months later.  Waiting wasn't such a good idea since it allow the body to "move" and the back to expand and contract independently. 

 If the instrument is going to be apart for very long, say more than a couple of days, I suggest that you rig some jig work to help support the shape of the body as you work on it. You should also make sure you have a workable solution to clamping up the body when you're ready to install the back again. A couple of "C" clamps probably won't do it unless you make some heavy cauls first.  It's actually possible to make a body board with some screw-in "L" hooks to support the sides and heavy rubber bands to hold the back in place as long as the face is supported at the edges and not levered over the end of the finger board. 

All this means that it's a LOT more work to remove and replace the back  but it will insure that you are able to really clean up the old glue and the new glue squeeze out plus you may find that there are other things that need your attention while you are at it. For someone that isn't working on a deadline, wants to "enhance the experience" and doesn't care all that much about keeping it all "original and pristine", it is, to me, more fun than working through a sound hole... particularly a very small sound hole.