Neck crack repair advice needed.

Discussion in 'Hardware, Setup & Repair [BG]' started by lo_freq_geek, Jun 18, 2020.

  1. I came across a Yamaha BB2000 that is in ok shape aside from an crack in the back of the neck along the darker wood in the laminate. It's pretty obvious to your thumb and palm when you are in the first few positions. I smoothed out the ultra thick 80s poly on the back of the neck with a green scrubee and it's better but still noticeable. It doesn't look like it was from abuse, it looks more like dry wood or weird grain maybe? It doesn't seem to be of structural importance, and doesn't open up if you twist (gently) on the headstock. It was still in tune from the last time it was played years ago! Pic attached.

    Should I just live with it, annoying as it is? Or try to fill it with glue (or filler) and smooth out? Otherwise it will be a cool bass with some TLC.

    Thanks in advance

    Attached Files:

  2. JIO

    JIO Be seeing you. Gold Supporting Member Commercial User

    Jun 30, 2010
    The Mission SF/CA
    musician/artist/owner - Gildaxe
    I'll guess it was turned into something, (mic, pole, wall) banged and the "cracks" are finish stress-cracks. You can see an indented dot on the darker stripe right at the source of the 'crack'. Wood is elastic- an old thick clear coat isn't.
    lo_freq_geek and Beej like this.
  3. dwizum


    Dec 21, 2018
    I agree, it looks like it may just be cracks in the finish. If it bothers you, you could remove the finish from the neck and refinish it. Removing the finish would also be a surefire way to tell if the crack is actually in the wood! If it turned out there were cracks in the wood, you could easily wick thin CA into it at that point. Then, refinish with something easy like wipe on oil based satin poly or tru oil, both of which are pretty foolproof and give that smooth fast natural-feeling finish most people seem to like.

    If it doesn't bother you, you may want to just keep an eye on it, and if the cracks seem to spread over time, drop fill them with CA to keep it stable.
    RSBBass and JIO like this.
  4. Huw Phillips

    Huw Phillips Life is like TV if the channel sucks change it Supporting Member

    Jan 4, 2019
    I recently discovered a product called “Birchwood and Casey gun stock sealer and filler“, I bought a neck on here that was a bit beat up but otherwise fine, I sanded it till smooth with 220/320 then put 3 coats of the product on and sanded with 320 then a green pad and am super happy with the neck, I would recommend this process highly.
  5. Turnaround

    Turnaround Commercial User

    May 6, 2004
    Toronto Canada
    Independent Instrument Technician - Retired
    CA - CyanoAcrylate a.k.a. super glue.
    JLS and lo_freq_geek like this.
  6. sissy kathy

    sissy kathy Back to Bass-ics Gold Supporting Member

    Apr 21, 2014
    Arbutus, MD
    If you enlarge that picture far enough (I can make the ding @JIO mentioned 35 mm wide [about 1.5 inches]), it becomes obvious those are not finish cracks. The darker wood is split and the split even jumps the grain making two distinct cracks, and they have debris in them. The finish does have some cracks on the outside laminate. The way the finish cracks are running parallel to one another makes me think this is from the wood being stressed.
    Last edited: Jun 19, 2020
    vid1900 likes this.
  7. That's what it looked like to me although it is difficult to tell from the pic. If this were your bass what would you do to fix this? It seems solid enough to me, but it feels weird in the hand (like a rough spot on a tooth that your tongue keeps finding) and I don't want it getting worse.
  8. vid1900


    Dec 12, 2019
    Looks like a stress crack from here, especially how it arcs upwards along the headstock heel.

    I'd not put any heavier or higher tension strings on it.

    What happens when you take the strings off? Does it creak or twist?
  9. Zero change in the crack w/o strings. It seems pretty stable, doesn't seem to twist.
    vid1900 likes this.
  10. FunkHead

    FunkHead Supporting Member

    Mar 10, 2007
    That looks very stable to me. I would sand it nice and smooth and add another coat or two of poly.
  11. vid1900


    Dec 12, 2019
    Don't wick any glue into the cracks, in case a pro repair is required in the future.

    If you have balls of steel, take a brand new, single edge razor blade; and using both hands, gently scrape the high point of the crack's finish.

    The razor should be at a 90* angle to the surface, not 45*. <- Read this again.

    Because the blade is brand new, it will just kiss the sharp edge of the crack.

    This will keep you from feeling it always with your thumb.
    lo_freq_geek likes this.
  12. sissy kathy

    sissy kathy Back to Bass-ics Gold Supporting Member

    Apr 21, 2014
    Arbutus, MD
    I know just enough about finishing wood to give bad advice. That said, I'd try to clean out the cracks with either the tip of a razor or some canned air and wick in some thin CA bringing it proud of the surface. Next, I'd sand/polish it smooth and call it a day. Do you suppose that will work?
    lo_freq_geek likes this.
  13. dwizum


    Dec 21, 2018
    @sissy kathy I'd say that is pretty good advice. Drop filling with CA is a pretty standard method of fixing cracks or chips in instrument finishes. Stewmac has a video on the process, you can ignore the part about adding the colored stain first but the razor blade trick is a good step to take since it results in a nice level repair that doesn't need aggressive sanding/buffing.

    Zooberwerx and vid1900 like this.
  14. Thanks for the excellent advice, I'm sure I can follow that video and make this better. In no way does this repair have to look pretty, just has to be stable and feel ok to the hand. This bass has lots of play wear and battle scars - it was used by high school jazz bands for 20+ years and not well maintained. It will be a jam/backup bass at best. I cleaned/polished the fretboard with 2 treatments of JJ Gorgomyte and it looks great. Found a truss rod wrench on Philadelphia luthier so I will be able to tweak the relief. I may try some really old TI flats if tension is going to be a concern. I will post after pics once I'm done.
  15. That sounds like a plan. I like the feel of a worn neck, and may work on the entire back of the neck a bit more with a new scrubee,