Old guitar with a bowed neck

Discussion in 'Acoustic Soundboard' started by Willmunny, Aug 18, 2021.

  1. Tremoluxer

    Tremoluxer Strat-Talker Gold Supporting Member

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    Heat lamps, aka incandescent lightbulbs, are a cheap way to heat a neck. I fixed by bandmate's Paris Swing GG-42 Gypsy Jazz Guitar that was left in a closet facing south, during the whole summer of 2018 -- in a thin-walled mobile home. The whole top/neck joint area had slipped, causing the guitar to be unplayable. A couple of days with a 100-watt lightbulb inside, and clamped to the workbench at each end of the guitar. Then let it cool for 24 hours. Worked like a charm! Better than waiting until the next summer, clamping it up, putting back into the closet for three months, and hoping for the best.

    It would be a bit more difficult to contain the heat from a lightbulb when straightening a neck, but certainly doable. I've used compression fretting, as Dan Erlewine shows in the StewMac book, Fret Work -- Step-By-Step. It was an old classical someone gave to me and it had a warped neck. I thought it was a beater so tossed into a corner for 10 years. Then I took a closer look. It was a Salamanca, built in postwar Germany in 1949, had a solid Engelmann Spruce top and was light as a feather. It needed a refret so, the compression method made sense. I ended up selling it in 2019 for $800. One oddity was the non-standard spacing for the tuning machines. The originals were junk, so I used individual classical tuning machines.


    05_Paris Swing Repair.jpeg


    07_Paris Swing Repair.jpeg


    06_Paris Swing Repair.jpeg


    A gap at the 14th fret, that was about 5/16", wound up at 1/10" (straight edge sitting on the bridge and nut) -- not too bad! The neck is strong, hard maple with a square profile -- the stiffest neck I've ever seen. The hot closet had no effect on it. My friend uses 10-44 D'Addario Gypsy Jazz strings, so not too much tension on the neck -- even though the scale length is 26.4".


    09_Paris Swing Repair.jpeg
     
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  2. Dain Bramage

    Dain Bramage Strat-Talker

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    This is a decent and tried answer, I would only add careful application of a heat gum to the fretboard during the process can loosen the glue and help the process, but I emphasize "careful" and recommend one try this on a less expensive unit, first, keeping some form of hydration in mind as well. I have also seen a master builder use a pizza oven and neck jig he had made; you have really got to want that to come back to life for that much trouble. This begs the overall question; is it worth that (-to you- is part "b" of that Q), and then the idea that experimenting and learning can be fun, disastrous, or both!
     
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  3. dirocyn

    dirocyn Most Honored Senior Member

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    I agree, some heat is likely to help.

    This is a $10 guitar, there's not much "less expensive" to go.
     
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  4. Willmunny

    Willmunny Senior Stratmaster Gold Supporting Member

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    The guitar is a 1986 takamine b 126 that I found on offerup for 10 bucks.
    I feel like it's a stray animal that I found and want to save. I played it a little with sky high action and that big bow, and it sounds pretty good.
    To be fair that classical fretboard seems huge to me lol. I have some low tension strings incoming. We will see how that pans out.
    Thanks again to all who replied
     
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  5. Willmunny

    Willmunny Senior Stratmaster Gold Supporting Member

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    Sorry g 126
     
  6. Willmunny

    Willmunny Senior Stratmaster Gold Supporting Member

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    FWIW update
    I put on some light strings, neck is still bowed more than I prefer but it's ok for now. Action is very high below the 7th fret. I need to do some more sanding on the saddle, about an eighth of an inch 20210823_102713.jpg 20210823_102741.jpg 20210823_102803.jpg
     
  7. CB91710

    CB91710 No GAS shortage here Double Platinum Supporting Member

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    You can only go so far with the saddle due to break angle and height above the soundboard.
    But you have to ask if it's worth having the neck reset.
    But considering it was $10, it's worth putting some money into it.
     
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  8. Riderock

    Riderock Strat-Talker

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    I've been thinking of trying something like this on a twisted neck on an old junk bass .
    U
     
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  9. dirocyn

    dirocyn Most Honored Senior Member

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    This is true. If you get the saddle too low, it will buzz at the saddle. But I think you can go a little lower than this one is, even on the high and low e strings.

    Also, @Willmunny I just noticed that saddle was made for an acoustic, not a classical. This guitar doesn't have a radius, why should the saddle?

    What I suggest is slack the strings and pull that saddle out, then re-tune (ballpark) with no saddle in. Take a look at how the strings lie with no saddle in, and the action. From there, decide if you can get away with simply a lower saddle, or whether you want to shave some height off the bridge or do more work on the neck.
     
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  10. CB91710

    CB91710 No GAS shortage here Double Platinum Supporting Member

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    There are also issues with the tone when the strings are too close to the soundboard.
    You really want that at or very close to 1/2"... no lower than 3/8"
     
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  11. dirocyn

    dirocyn Most Honored Senior Member

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    Yes, absolutely. On a flat-top the saddle rocking forwards & backwards is the primary mechanism that makes the soundboard move. The saddle is a lever--much like working with a short ratchet wrench vs. a breaker bar, the longer the saddle the easier it is for the string to move the soundboard. Shortening the saddle will make a quieter guitar, and there may be some knock-on effects on timbre as well.


    This rule of thumb I'm less familiar with. My #1 classical has 5/8" between the string and soundboard right in front of the bridge. My other classical has 1/2". None of my flat tops has less than 3/8". So I accept 3/8" to 1/2" being the normal range. Also, I suspect you'd have to shave down the bridge (not just the saddle) to get as low as 3/8".
     
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  12. CB91710

    CB91710 No GAS shortage here Double Platinum Supporting Member

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    Ya... 3/8" would be the minimum, 1/2" better, but obviously, that doesn't preclude designs with floating bridges such as archtops being much higher.

    I've always viewed shaving the bridge material as a last resort and only if it's still not going to end up wanting a neck reset in a couple of years.

    Reminds me that I should probably pull my old Sigma 12 string out of storage and check it.
     
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  13. 3bolt79

    3bolt79 Dr. Stratster

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    Call Strings by Mail and ask them about what string sets they have in about the 80lbs of tension range. Labella has a few, and they are not expensive. I think the set you’re after is the LaBella 471. But I can’t really remember the set name. That is really low tension.
     
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  14. dirocyn

    dirocyn Most Honored Senior Member

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    My usual set is D'Addario Pro Arte EJ45, "normal tension" which means 85.85 lbs. EJ43 is light tension, 79.81lbs.

    IDK if La Bella has lighter than that--it's possible, but it was a little harder to find string tension info there.
     
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  15. 3bolt79

    3bolt79 Dr. Stratster

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    I think that the labella was 78 point something. 2 lbs isn’t going to make much of a difference.
     
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  16. Willmunny

    Willmunny Senior Stratmaster Gold Supporting Member

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    Not sure of the tension but I used these 20210827_090411.jpg it still needs a neck reset, even though some earlier posters said 1/2 inch of action lower on the neck was reasonable. I am still going to lower the saddle a bit as well
    I will do the iron method in the near future.
    Actually sounds good and plays decent on the 5th fret and higher.
    Thanks again for all the feedback
     
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  17. 3bolt79

    3bolt79 Dr. Stratster

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    79.81 lbs for that set
     
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  18. Slacker G

    Slacker G Strat-O-Master

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    If all else fails:

    Take up archery.
     
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  19. Willmunny

    Willmunny Senior Stratmaster Gold Supporting Member

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    Lol