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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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  4. #29

    Default Re: Odd headstock repair

    Well, the results are in and they are good!

    I let everything set and dry while I ordered a set of special light strings for a bowl back as suggested in another post. They never arrived and when I went to re-order, everything was back ordered, but I managed to find a set of Optima Consort bronze strings (.01-.033) and they arrived a day ago. I have to say, I strung this up with great trepidation. Not only was I concerned that it hold together under tension, I was worried that it might not be playable or at least close enough I could adjust it it.

    I got lucky! When I strung it up, not only did it all come together, but the action turned out to be right on the money. It plays well and in tune and has a surprisingly deep tone I didn't expect to hear. My experience playing bowl backs is limited, but I'd guess it must be the Brazilian Rosewood back. I'll record a video and get a link up soon. In the meantime, here are some pics.

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  6. #30
    Registered User StringMeAlong's Avatar
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    Colorado
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    Default Re: Odd headstock repair

    Wow, it's looking really nice! I've been following your repair adventure and it sure looked daunting from the start. Congrats! I can't wait for a video.

  7. #31

    Default Re: Odd headstock repair

    This is my first video posting so hope I got it right. Recorded with a large diaphragm condenser mic about 3 feet away from the mandolin, head high.


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