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Bass bar trouble

Discussion in 'Setup & Repair [DB]' started by PaulKing, Sep 17, 2010.


  1. PaulKing

    PaulKing

    Apr 17, 2004
    London, UK
    Bit of misery here.. my old King Mortone is buzzing. I'm convinced it's the bass bar.

    Seams are good, bridge is snug, post is tight. I've checked wires, pickups, tailpiece etc.

    The sound is coming from inside, loudest at E-side f-hole.

    Light pressure on the top, right over the bass-bar, stops the buzz. Light pressure elsewhere doesn't .. though of course heavy pressure stops it wherever applied.


    So, before I send it off to the luthier and kiss goodbye to a couple hundred quid ... anyone any magical tips / techniques for firming up a loose bass bar?


    Not expecting anything but worth a try...
     
  2. JtheJazzMan

    JtheJazzMan

    Apr 10, 2006
    Australia
    De ja vu, I had exactly the same problem as you, exact symptoms - and I was sure it was the bass bar.

    The problem was a slightly popped seam where the end block meets the top. A few bucks of gelatin and some clamps later, I fixed it myself. Where the sound comes from is very deceptive.

    Have you tried tapping around the seams to listen for any loose areas?
     
  3. PaulKing

    PaulKing

    Apr 17, 2004
    London, UK
    That's what I have to do. Thanks .. yeah surprising how the sound can deceive you. I'm convinced it is coming from inside but you're right, I need to check.

    There IS a slightly loose seam ... though I'm convinced it's not that...

    Cheers!
     
  4. PaulKing

    PaulKing

    Apr 17, 2004
    London, UK
    OK maybe it is a seam, upper corner of E side C bout.

    So, any DIY tips?
    Step 1 is Get some granular hide glue I know.
    Then ... hot knife the corner open enough to squeeze in some glue? Do I need a syringe or something?
     
  5. Matthew Tucker

    Matthew Tucker Commercial User

    Aug 21, 2002
    Sydney, Australia
    Owner: Bresque Basses, Sydney Basses and Cellos
    slide the glue in on the warm thin knife blade then clamp.
     
  6. Gearhead43

    Gearhead43

    Nov 25, 2007
    NorCal
    +1 exactly how I did it.
     
  7. Figure a way to wipe the excess up w. a damp sponge and then dry w. a towel or rag and then clamp. It makes the job look more professional and clean... Take it from a Ham and Egger like me :D
     
  8. PaulKing

    PaulKing

    Apr 17, 2004
    London, UK
    Thanks all.
    Cleaned it all out nicely with hot knife, buzz gone immediately.
    Off to get a clamp now, granular glue on the way.

    PVA yeah, that's the right stuff...?












    ;)
     
  9. Matthew Tucker

    Matthew Tucker Commercial User

    Aug 21, 2002
    Sydney, Australia
    Owner: Bresque Basses, Sydney Basses and Cellos
    or duct tape
     
  10. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    Not being a luthier, I probably used the wrong proportions of glue and water when I fixed my bass. To the OP, I suggest finding out the correct recipe before proceeding.
     
  11. PaulKing

    PaulKing

    Apr 17, 2004
    London, UK
    Cheers . yeah I'll check on proportions. I've read top glue should be thinner than elsewhere, to facilitate later popping.


    PS HPF Pre gets big thumbs up from the guys over at DBC.com
     
  12. When you find out the proportions, would you report back here?
    I could sure use that bit of info as well.
     
  13. Matthew Tucker

    Matthew Tucker Commercial User

    Aug 21, 2002
    Sydney, Australia
    Owner: Bresque Basses, Sydney Basses and Cellos
    For me, making up hide glue is like cooking; not an exact science. Depends on the ingredients, too. HHG comes in may flavours! Usually, whereas glue for glueing things like bass bars and necks runs off the brush like cream or hot honey, glue for tops runs more like milk.
     
  14. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    All's I know is that I made it up way too thick when I reassembled my Kay, and used up half my life's supply of curse words in an afternoon.
     
  15. Jake deVilliers

    Jake deVilliers Commercial User

    May 24, 2006
    Crescent Beach, BC
    Owner of The Bass Spa, String Repairman at Long & McQuade Vancouver
    When its a critical joint I mix my 192 gram strength granulated hide glue at 1 part granules to 1.8 parts water by weight. Just perfect. ;)
     
  16. PaulKing

    PaulKing

    Apr 17, 2004
    London, UK
    I ballsed up the glueing. So here, tell me what I did wrong. Was the glue not hot enough? Not long enough to set?

    Followed instructions to melt it, diluted about 50/50 or maybe slightly more. Consistency was like gooey honey. Looked good. Not boiling water in the jacket, but pretty hot to touch.

    Used warmed knife to slide glue into seam, then clamped it shut and wiped off exceess. Took quite a bit of bending to pull the seam closed ... I've a feeling the space was simply filled with glue before.

    Result. After 2 hours I checked it. Glue wasn't properly set so seam pulled open. Quickly clamped shut again.

    4 hrs, removed clamp (had a gig to go to). Seam was closed, but the laminating started to open up. The ply must be under a lot of tension...
    Plus, when I played, the buzz was as bad as ever. So, the hot knife went back in, opened up the seam and played the gig with it open, but at least quiet.

    The glue left in the pot has cooled to a very firm rubbery texture, like a bouncy ball.
    Should it be rock solid?
    Did I need to heat the glue more first?
    Should I try again but fill the gap with glue and not clamp the corner so tightly closed?
     
  17. Matthew Tucker

    Matthew Tucker Commercial User

    Aug 21, 2002
    Sydney, Australia
    Owner: Bresque Basses, Sydney Basses and Cellos
    Once the glue cools and gels it won't stick any more ... you opened it too soon. you can't re-clamp it. detune your strings a bit. Heat the knife again in very hot water. Work it into the seam and re-melt the glue. clamp tight immediately and leave it for 12 hours. rubbery glue in the pot is normal, but your mixture sounds thick.
     
  18. PaulKing

    PaulKing

    Apr 17, 2004
    London, UK
    Ta Matthew.
     
  19. Jake deVilliers

    Jake deVilliers Commercial User

    May 24, 2006
    Crescent Beach, BC
    Owner of The Bass Spa, String Repairman at Long & McQuade Vancouver
    What Matthew said plus - hide glue needs to be runny and it sounds as though your mix is too thick. More like maple syrup, less like honey! ;)

    A candy thermometer or espresso thermometer will help you get it to 140 degrees F. which is the best temperature for hide - it gives you a little more time before it gels but isn't so hot that the proteins break down and render it useless.

    It almost sounds as though you should be cleaning that seam out with hot water and a brush before you attempt to glue it again. Let it dry and try again.

    Preheating the area with a desk/work lamp will give you more time to clamp it before it gels.

    Good luck!
     
  20. PaulKing

    PaulKing

    Apr 17, 2004
    London, UK
    Precious words Jake, ta.
     
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