Sanding fretless fingerboard...

Discussion in 'Luthier's Corner' started by Gastambide, Mar 18, 2006.

  1. Gastambide


    Mar 4, 2005
    I have a converted fretless Ibanez mini-Musician with a rosewood fingerboard that has been nicely (professionally) splined with ebony fretlines. I am considering a "do-it-yourself" System 3 resin coating, using the tutorial here on Talkbass forums, in leu of having someone else like Thor or Pedulla do the job. (For one thing, I don't have an extra $300 + lying around, and for another, I don't want to ship off my bass for a many-months-long vacation!) However, I need a bit of professional advice before delving into this project...

    First, I would like to get the fingerboard a uniform color. I suppose I could use and ebony stain, but what about the pearl dot inlays? Should I just sand 'em down along with the rest of the board, then paint 'em to match the ebony? Or should I try to remove them and replace with a stainable wood product (which sounds like a REAL pain in the ass)? And will paint be affected by System 3 Mirror coat?

    Second, I realize I need a proper radiused sanding block, but how the heck do I measure the radius of the fingerboard so I can get the proper block for the job?

    Lastly, the tutorial doesn't give any real details on properly masking the neck's fingerboard edges prior to applying the Mirror Coat. Where can I dig up more info on this?

    Any expert advice would be appreciated. (Although the best advice is probably, "Don't do it! Hire a pro.") But any light you could shed would be helpful.


  2. Rodent

    Rodent Supporting Member Commercial User

    Dec 20, 2004
    Upper Left Corner (Seattle)
    Player-Builder-Founder: Regenerate Guitar Works
    it's easy to discover the fingerboard radius ... all you need is some paper and a compass

    1) Carefully set your compass to a 9-/12" radius and draw and arc wider than you fingerboard where you want to measure
    2) carefully cut out the arc
    3) place it on the fingerboard

    if it's an exact match you now know your fingerboard radius.

    * if there is a gap in the middle and the edges are touching, the radius is too small ... move to a 12" radius and repeat ... if it's still too small, try a 16" radius

    * if there is a gap on the edges and the middle is touching, then your radius is too large ... repeat the process with a smaller radius and try again

    depending on the manufacturer, you may have a compound radius board - one where you have one defined radius value at the nut and and another set value at the 24th fret, with an evenly tapering radius value between these points. If you plan to do any block sanding by hand, you'll need several radius block sizes and a lot of attention to detail as you switch betwen blocks along the neck

    all the best,

  3. nateo

    nateo Schubie Fan #1

    Mar 2, 2003
    Ottawa, Ontario
    That may well be the best advice, but it's not the kind you're likely to get in this particular forum. If we all listened to that advice most of us wouldn't know what we do today and there would likely be far fewer molested pieces of wood in the world. There'd also only be a tiny fraction of the ideas and innovations that come from some guy in his home shop saying "Huh, now how the heck do I do that?"

  4. Aren't there radius gauges available? I think I saw them at Stew-Mac for instance.

    Dang... Are there actually people that do a compound radius by hand?? Nuttin' but respect for that!
  5. Rodent

    Rodent Supporting Member Commercial User

    Dec 20, 2004
    Upper Left Corner (Seattle)
    Player-Builder-Founder: Regenerate Guitar Works
    ... sure, you can buy a set of radius gauges from StewMac - but besides the week wait for shipping them your way, they cost a whole bunch more than that small scrap of paper.

    If you don't have a compass, a string tied around a pencil can work just as well if you measure accurately.

    all the best,