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crack repair question

Discussion in 'Hardware, Setup & Repair [BG]' started by madmachinist, Jan 31, 2014.

  1. madmachinist


    Dec 28, 2008
    ok , it's not a bass (1930's Martin -A flatback mandolin) , but it has a 3" hairline crack in the lower -mid left of the rosewood
    back . i don't want it to spread and become a split .

    it is a roundhole instrument , so i could possibly glue in a patch
    from the rear if i had to access it .

    my thoughts are :

    a) vee it out , superglue the crack and fill it...

    b) keyhole it on the ends with a small hole
    fill the crack and leave it alone

    c) patch on the inside and fill the gap on the outside with

    some stock photos of (not my) instrument:


    any suggestions would be appreciated.
  2. RSBBass


    Jun 11, 2011
    First, here is a great resource where you are likely to find more info than a forum that mostly covers solid body electric instruments:


    Second a 1930's Martin is way too good of an instrument to be learning repairs on.

    Third evaluating a crack and the best way to repair it involves looking at it, preferably in person but good pictures are a huge help.

    Finally, hairline cracks are not unusual in the winter. It may heal itself if you get a room humidifier.
  3. 96tbird

    96tbird PLEASE STAND BY Supporting Member

    Professional help is indicated.
  4. pfox14


    Dec 22, 2013
    The proper way to fix a crack like that is a glued in thin piece of rosewood (usually called a cleat), which can be done through the sound hole. I would take it to a good luthier to have the work done.
  5. Don't even need to V it out. Get yourself two bar clamps with soft tips and glue it and clamp it quickly. I use Super-thin super glue for these type of repairs.
  6. walterw

    walterw Supportive Fender Gold Supporting Member Commercial User

    Feb 20, 2009
    +1 to no guessing or OTJ training here, you get one shot to get it right.

    +1 also to talkbass being an odd place to even ask about it! the fact that you asked it here frankly makes me even more inclined to second the "let a pro do it" advice.
  7. SirMjac28

    SirMjac28 Patiently Waiting For The Next British Invasion

    Aug 25, 2010
    The Great Midwest
  8. P Town

    P Town

    Dec 7, 2011
    "+1 also to talkbass being an odd place to even ask about it! the fact that you asked it here frankly makes me even more inclined to second the "let a pro do it" advice."

    Hey, don't be so quick to say this is the wrong place.

    There are a LOT of VERY SMART people on this forum.

    I have been thinking of asking for medical, investment, and legal advice here.
  9. Pilgrim

    Pilgrim Supporting Member

    Please keep in mind that any such advice is worth exactly what it cost you. ;)

    What stands out to me is that this is indeed a repair you only get one shot at. I would either do one helluva lot more homework than posting on an Internet forum, or take it to a pro.
  10. P Town

    P Town

    Dec 7, 2011
    I've paid big bucks to professionals for advice in all three areas that turned out to be worthless.