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Thread: Odd headstock repair

  1. #26

    Default Re: Odd headstock repair

    Excellent conversation! Thanks very much for your insights. I agree that drilling for dowels won't work here. I've been studying the joint (measure 3 times, cut once!) and there simply isn't enough material to support any drilling. It's been 2 full days + since I glued it and I'm in no hurry to move forward yet... time is always your friend in restorations! I've carefully stressed the joint enough to know it is at least solid and I'll wait several more days before doing anything more.

    Here are my thoughts at the moment. I've measured the wood at the neck joint. At it's thinest point, it measures .36" and that represents the high point. The center of the top is scooped out about 1/8" and the back has 2 grooves cut into the headstock curl making the structural part even thinner. The thickest part, right over the break, appears to be .72" thick at the thick point. As Richard 500 suggested above, the best plan may be remove as much material as I can safely do from inside, and replace it with new wood and a glue joint with a large surface area. Due to the thin nature of the material, I don't believe there's room to do a beam, but I should be able to do a fairly flat patch about 1" long glued into the inside of the headstock. I think I might be able to go another 1/8th if I'm lucky and careful. That might be enough. I'll continue to ponder.

  2. #27
    Registered User Tom C's Avatar
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    Default Re: Odd headstock repair

    I have the same mando but without the fret board inlays.

  3. #28

    Default Re: Odd headstock repair

    After much though and careful observation, here's what I ended up doing. The wood was indeed so thin that I determined that I couldn't effectively carve anything out. The only effective way to support the are would be to sand smooth the chiseled out "scoop" and inlay new wood on that section.

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    I first tried using a wine bottle cork with adhesive sanding paper, but quickly realized that if I wanted to get the strongest bond, I needed a perfect fit. Ultimately, I bought a 1.25" road (staircase hand hold) and cut a short section and covered it with adhesive sandpaper. This dimension matched the curve of the 'scoop" and I was able to sand smooth the channel bottom very nicely and evenly. I had a trough of about .13" at the deepest point so I took maple stock I had that was 1.5" thick and sanded it roughly to the shape of the curve of the trough.

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    After a certain point, I began to use the Carbon Paper fit method like I use for neck re-sets to fine tune the fit. After about 2 hours of marking and shaving the high spots, I got an very good fit.

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    One final cleanup and it was ready to glue. At this point, the break had been glued for well over a week. Glueing in the support piece was relatively easy. I used a new batch of HHG, clamped it up and let it sit for 24 hrs before removing the clamps.

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    The result sits just a bit above the original edge of the "trough" but the tuners fit fine and I'll just leave the extra material there for added strength.

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    There were also two small sections of wood that'd broken out when the headstock broke off. This is where the two screws attached the tuning machines by the nut. I had one piece which I glued back in (and will inlay additional wood to fill the small void) and I'll just inlay new wood for the other.

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