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Thread: Detached back

  1. #1
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    Default Detached back

    I need guidance on a repair. My mandolin suffered a jolt that resulted in the back becoming partially detached. What course of action should a repair tech be presenting to me?

    Thanks in advance.

  2. #2
    Registered User sunburst's Avatar
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    Default Re: Detached back

    Not enough info. Pictures would help.
    Is the back loose from the rim? from the tail block? from the neck heel?
    Is the lining inside damaged? is it still glued to the rim? to the back?
    What kind of mandolin is it? carved arched? flat top/back?
    Does it have back binding and is it intact? does it meet the rim at the back glue joint or below it?

    Any and all info will help you get answers.

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    Default Re: Detached back

    Thanks John. Back is separated at the tail block to about 1/3 around on both sides.
    The gap isn’t open enough for me to detect interior condition.
    Instrument is 18 yr old Eastman 615.
    Binding on the back appears intact.
    I’m not understanding your last question.
    I’ll try to get a picture uploaded tomorrow.

    One interesting point: I was in a summer home near the coast when this occurred. The widest part of the gap was approaching 1/4”. Now that I’m in a less humid environment, the gap has almost closed, presumably due to change in humidity.

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    Default Re: Detached back

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    Blue tape isolates the area of separation. Looking down, the back appears to “underlap” the body at the tail, photo second from left. Perhaps due to string tension? I haven’t detuned.

  5. #5

    Default Re: Detached back

    Not sure what kind of glue Eastman was using back then, I'm guessing not PVA. Should be a straight forward repair for a competent repairman. More expert heads will weigh in I'm sure. I'm guessing at 18 years old, that's a nice sounding mandolin.

  6. #6
    Registered User sunburst's Avatar
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    Default Re: Detached back

    Quote Originally Posted by A-board View Post
    ...Perhaps due to string tension? I haven’t detuned.
    Yes, at least partly due to string tension, please release string tension (should have as soon as the problem was noticed)!

    A relatively straight forward repair for a competent repair person, as Rob Roy said. Most likely will need to put in a jig to correct the "underlap", clean, glue and clamp the joint.

  7. #7
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    Default Re: Detached back

    Quote Originally Posted by sunburst View Post
    Yes, at least partly due to string tension, please release string tension (should have as soon as the problem was noticed)!

    A relatively straight forward repair for a competent repair person, as Rob Roy said. Most likely will need to put in a jig to correct the "underlap", clean, glue and clamp the joint.
    IF . . . the tail block has not come loose . . .
    Which can also be fixed, but takes more time and effort.

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    Default Re: Detached back

    Thank you for the insights. These are the responses I hoped for. I’ll update when the job is done.

    And Rob Roy, it does have nice sound, not as resonant as my Silverangel, but it’s enjoyable to play. I had a CA bridge installed and a refret not long ago, making it a keeper.

  9. #9
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    Default Re: Detached back

    Repair completed. Very slight “under lap” where back meets tail, maybe 1/32”. Discussed with luthier before repair: potential risk of popping something else with pressure applied to make a perfect alignment. It’s noticeable only upon very close inspection. Sound is unchanged.

    This is my main play-out mandolin, so no concerns about impacting value. Further, it was the perfect time to have an internal pickup installed.
    Girouard A
    Silverangel A
    Eastman 615-tweaked

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