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Help!! Problem with joined top wood

Discussion in 'Luthier's Corner' started by HARD HAT, Nov 29, 2006.


  1. I just ran into a big problem ( for me at least ) with the top for my first bass. I had run my two bookmatched pieces through a joiner, cut out a notch to fit around my fretboard, and glued and clamped it just before I went on a little vacation with my family last week. This weekend I glued the top to my body and left it clamped-up for 24 hours or so. I had wax paper covering the top to keep the clamps from getting glued to anything so I couldn't see the top very well while it was clamped up and drying. I removed the clamps Monday after work and found under the wax paper that my joined top had seperated along the centerline from the fretboard for about 5 or 6 inches toward the end of the body. It's not a huge opening - I can just get an exacto blade in there. I can't figure out what happened and need some advise for a fix. I/m open to all suggestions because it all looks really good except for that stinkin' gap.
     
  2. Basschair

    Basschair .............. Supporting Member

    Feb 5, 2004
    Stockton, Ca
    Just out of morbid curiousity, do you have a pic?

    Also, I'm wondering if you planed/jointed the seems that you initially glued together, and made sure to match them up to check for gaps?
     
  3. I do have a picture but I'm not sure how to post it. And yes, the top had been together for several days and with no gaps showing. In fact, I'm building this at work during my lunch time (for the space available in the back shop ) and had showed it off a little and everyone was impressed with how good the joint looked. I just can't figure it out.
     
  4. Jeronimofesto

    Jeronimofesto Luthier: JC Basses

    Oct 17, 2006
    Auburn, CA
    I say you route out a thin line down the center of the two pieces and fill it in with a contrasting wood. Like if you have a light top, fill in that line with ebony or something like that.
     
  5. you could do that, or fill it up with wood dust (from a scrap piece from the top wood), dab some drops of CA and then sand level. Either way will work and both will look nice.
     
  6. Here is a picture ( I hope ) if this will help anyone with some ideas for a fix without running a contrasting stripe through there. I have Purpleheart stripes in the neck and in the body laminates, so I have considered it... it just wasen't the original vision for the top, View attachment 46434
     
  7. Basschair

    Basschair .............. Supporting Member

    Feb 5, 2004
    Stockton, Ca
    This is just a guess, but...

    was your body core as close to perfectly flat as can be? I'm wondering if, in the original glue up of the bookmatch top, the glue didn't completely penetrate the seam from front to back. The top looked like it had a tight seem, but once it was clamped down to the core, it forced the top to swell outwards in the middle just enough to reveal that portion of the seam that didn't glue together completely.

    Did that make sense? At any rate, figuring the cause will only help with figuring how to not do it again on the next build. In the meantime, I think Wilser's idea is the most appropriate, if you can get wood dust from the scrap that will match the color of the surrounding wood.
     
  8. I still vote for the CA and wood dust, you can sand that area and leave the wood that remains in the seam, then apply the CA and sand again ...I have fixed many a ding and tear out from spokeshaves that way and they become invisible once finished. If it comes out bad, you can always go back to the contrasting strip.

    BTW, I have a bass in process (for over a year now!) that has a top just like that! it's very beautiful.
     
  9. Thanks for all the help guys. I'll try the wood dust and C.A. first. If that doesen't work, I guess I'll go with a Purpleheart stripe. Thanks again all.
     
  10. Rodent

    Rodent A Killer Pickup Line™ Commercial User

    Dec 20, 2004
    Upper Left Corner (Seattle)
    Player-Builder-Founder: Honey Badger Pickups & Regenerate Guitar Works
    not to worry ... you'll never see the crack once you install the pickguard



    :bag:


    R
     
  11. Holmann

    Holmann

    Dec 23, 2005
    Ashland, WI
    What type of glue did you use, and how old was it?
     
  12. Bassic83

    Bassic83

    Jul 26, 2004
    Texas, USSA
    The black paint should cover it- might want to patch it with Bondo, just to make sure! ;)

    All kidding aside, if you do the CA thing, it will be almost invisible.
     
  13. gr8estbassist

    gr8estbassist Guest

    Oct 9, 2004
    South East
    what is "C.A."?
     
  14. The body core top ( which is a neckthrough if that matters )was flat and level when i spread out the glue for the top. I used original Titebond glue from Home Depot.. it might have been sitting in the store for a while but all my other glue joints have been fine with this same bottle. I'm beginning to wonder if something ( woodchip, dirt, boulder )was on the body top when I covered it with glue and it was just big enough to cause upward pressure on the joint to seperate it when clamped. Maybe we'll never know.
     
  15. Basschair

    Basschair .............. Supporting Member

    Feb 5, 2004
    Stockton, Ca
    Could be. I still think Wilser is giving the best advice: try the CA glue and dust, and if it doesn't work just cut out a channel and fill it with a strip. It'll still be a beaut!

     
  16. Musiclogic

    Musiclogic Commercial User

    Aug 6, 2005
    Southwest Michigan
    Owner/Builder: HJC Customs USA, The Cool Lute, C G O
    This is a little tougher than CA and dust, but does a much better job.

    clean out the seperation with your x-acto, make some ribbons of matching maple with a spokeshave or hand plane. Place woodglue in the seperation and use the ribbons to fill the gap. Lay a piece of wax or parchment paper over the the fill, and place some weight on the repair. Let sit overnight, and sand smooth. This technique can be done multiple times to make the fill completely invisible, and still absorb stain if you plan on staining the wood, plus it looks like the grain and not just filler. Just thought I would mention this approach as an option.
     
  17. Rodent

    Rodent A Killer Pickup Line™ Commercial User

    Dec 20, 2004
    Upper Left Corner (Seattle)
    Player-Builder-Founder: Honey Badger Pickups & Regenerate Guitar Works
    nice idea ML ... I'll definitely add this to my log of notes to reference for those 'special' occasions

    all the best,

    R
     
  18. Musiclogic

    Musiclogic Commercial User

    Aug 6, 2005
    Southwest Michigan
    Owner/Builder: HJC Customs USA, The Cool Lute, C G O
    It's a technique I learned a long time ago to repair cracks in acoustic tops. It works great on any crack or gap in wood, and helps to retain a consistent grain appearence. Just wanted to relay it.

    JC
     
  19. an old friend of mine always said that you can pretty much judge a man's character by his willingness to share his knowledge.

    This is good stuff and I will certainly keep it in mind for when the opportunity comes.

    You ROCK!
     

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