Ebony block inlays in maple fretboard - is the density difference a problem?

Discussion in 'Luthier's Corner' started by Alan i guess, Mar 17, 2020.

  1. Alan i guess

    Alan i guess

    Mar 6, 2020
    Okay more specifically... Not block inlays but the ones that just go all the way across the fret. Like a shallow dado (not totally set on ebony but considering it - I'd like to use wood as opposed to plastic composites or whatever). I'm just wondering if the difference in the densities of the woods will give me any trouble as they flex and expand and contract with varying humidity, temperature, etc. Any insight is appreciated!

    Alan
     
    TonyP- likes this.
  2. Beej

    Beej

    Feb 10, 2007
    Vancouver Island
    Fretless or fretted?
     
  3. Slidlow

    Slidlow The Human CNC

    Apr 15, 2009
    Oshawa, Canada
    Depends on glue if it would be affected appreciably by humidity/temp changes.
     
  4. Alan i guess

    Alan i guess

    Mar 6, 2020
    Fretted
     
  5. Alan i guess

    Alan i guess

    Mar 6, 2020
    What do you mean by that? I would use titebond 3 for the inlays.
     
  6. Slidlow

    Slidlow The Human CNC

    Apr 15, 2009
    Oshawa, Canada
    You need a glue that cannot creep, epoxy might be better.
     
    Alan i guess and bobdabilder like this.
  7. I would use tinted epoxy for the inlays.
     
    andruca likes this.
  8. Sooner Boomer

    Sooner Boomer

    Feb 11, 2020
    To minimize unequal changes, the grain in the neck and inlay need to both be going in the same direction. Obviously, the grain runs the length of the neck, the grain in the inlay shoud also. The greatest change is in the direction of the grain. The thinner the inlay, the less problem there will be. If you can get a precise fit, titebond is a fine glue. If you have much gap to fill, I'd use epoxy, maybe tinted black with the addition of a smidge of tempra paint (dry), or some laser toner.
     
  9. dwizum

    dwizum

    Dec 21, 2018
    Maybe it's just me but I'm still struggling to picture a block inlay that goes "all the way across the fret" - does anyone have a photo of this?
     
    thetragichero and J_Bass like this.
  10. nilorius

    nilorius Inactive

    Oct 27, 2016
    Riga - Latvia
    pics ???
     
  11. "all the way across a fret".... what does this mean?
     
    J_Bass likes this.
  12. micguy

    micguy

    May 17, 2011
    I've often thought that Block inlays were....not the best idea, structurally. The more grain you interrupt, the less robust a neck is. All my basses are free of position makers - partly because I like that look, but also because I like them as strong and stable as possible.
     
  13. Slidlow

    Slidlow The Human CNC

    Apr 15, 2009
    Oshawa, Canada
    Most inlays are 1/16" deep and if glued properly do not impact rigidity of the neck in any appreciable way. No offense but that is another of the many myths that are out there. Go into your basement and see how many holes are drilled into your floor joists for wires and such.
     
  14. micguy

    micguy

    May 17, 2011
    Whether or not it's an appreciable difference depends on your definition of "appreciable". Call it a myth if you want, I'll just do the math. Stiffness goes up by the thickness cubed - .05" more thickness on a 1 inch thick beam adds 16 percent in stiffness. If it's a thin neck (like a Geddy J), then the difference is a bit more near the nut.
     
  15. dwizum

    dwizum

    Dec 21, 2018
    Can you quantify the impact of removing a piece of wood, then gluing in a separate piece of wood? Something tells me it's not as significant as simply removing material (making the beam thinner).

    Also, can you quantify the amount of stiffness we need in a neck? I have no data myself, but I feel that it's probably trivial (and very common) to build necks that are way stiffer than they "need" to be.
     
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  16. nilorius

    nilorius Inactive

    Oct 27, 2016
    Riga - Latvia
    Ebony inlays may sometimes be worste plastic inlays like ebonol for living, but the sound is more humanoid.
     
  17. gln1955

    gln1955 Supporting Member

    Aug 25, 2014
    Ohio, USA
    I one worries about inlays, one should REALLY worry about frets. Twenty+ deeper slots going all the way across the board.
     
  18. micguy

    micguy

    May 17, 2011
    Luckily, the frets are in compression. You really wouldn't want to cut slots on the back side of the neck, as those fibers are in tension. Fret slots are cut so that they're typically an interference fit. If they're glued as well, so much the better. Inlays are done in different ways - some good, some not as good.
     
  19. Slidlow

    Slidlow The Human CNC

    Apr 15, 2009
    Oshawa, Canada
    So if large ebony inlays are glued in with an epoxy (and one that cures hard) then technically they would also be in compression and hence the beam thickness wouldn't be compromised. As the ebony would have a crushing strength greater then the maple then maybe you can add that to your equation? I think this is being overthought.
     
  20. micguy

    micguy

    May 17, 2011
    If the epoxy is done right along the edges, so that the fibers there are in compression (without a gap at the joint), yes, it could be made to work. The biggest question is if the edges would separate over time with humidity cycles, epoxy shrinkage, etc.

    Yes, we're probably overthinking at this point.
     
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