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I'm not sure how serious this is, but I may be needing help quick!

Discussion in 'Luthier's Corner' started by Basschair, Jul 15, 2005.

  1. Basschair

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

    Feb 5, 2004
    Stockton, Ca
    The body of the bass that I'm making is quartersawn bubinga, and today I started my finishing sanding. I get to the "butt" end between the straplock and the jack and I see what appear to be scratches in the end grain running horizontal to the top (actually, they're at a bit of an angle...about 20 degrees to the horizontal axis: if the bass were laying down and you were looking at the end, they run from slightly lower left to upper right).

    Anyway, I'm sanding and sanding, and they won't go away. Turns out that they are hairline cracks. Is this called "checking?" What can I do to make sure it's stable? There's no seperation in the wood, but I want to be certain that it's can/will be taken care of.

    I've attached a pic: hopefully you can see what I'm seeing.
  2. Some of this stuff can be the figure of the wood itself. I can't tell by your picture, but I worked on some alder starting the year that had some lines similar to that (dark, though) and they were not scratches, but features of the wood figure.
  3. thedoctor


    Jun 20, 2005
    Damndest thing I have ever seen. I really like it, though. It goes in the wrong direction to be growth interuption so my best guess is chemical contamination after the log was cut.
  4. Bass Kahuna

    Bass Kahuna

    Dec 3, 2002
    West Lafayette, Indiana
    Luthier, Custom Builder
    hmm... don't look like cracks... sure it's not medullar rays (did I spell that right?...).

    I'd check with Larry over at Gallery Hardwoods... run the pic by him.
  5. nateo

    nateo Schubie Fan #1

    Mar 2, 2003
    Ottawa, Ontario
    If they are cracks then CA would surely solve the stability problem. Of course, it'd also limit your finishing choices as I don't think oil will absorb into CA coated wood. Just a thought.


  6. Gotta ask - and this isn't being nasty in any way - How do you know they are cracks if there isn't any separation in the wood? Usually, you would be able to catch a fingernail on an edge, or flex them a little to open and get a good diagnosis that way.

    From the pic, they don't look like cracks at all - they run counter to any direction a crack would go if it started in that particular location. Stress cracks will split the wood with the grain and that's fairly predictable as to direction.

    I think they might be scratches in the end grain and because it's end grain, they are more defined and tougher to eliminate than if they were anywhere else.
  7. Fasoldt Basses

    Fasoldt Basses

    Mar 22, 2005
    Stevens Point, WI
    Karl Thompson, Builder (Formerly Fat Karl)
    That would be my guess too. I've had this problem before, mostly in maple.
  8. Basschair

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

    Feb 5, 2004
    Stockton, Ca
    Nasty :eyebrow: ? :D

    Seriously, I can feel them and bump a nail on them when running over that part of the wood. Still, it didn't seem like the logical shape/direction of a crack. I've gone over it quite a few times with a r/o sander, and they just stick around. Odd. I'm not going to worry about it for now, as there's no seperation in the wood.

    Thanks folks!
  9. Fasoldt Basses

    Fasoldt Basses

    Mar 22, 2005
    Stevens Point, WI
    Karl Thompson, Builder (Formerly Fat Karl)
    And when you put a finish on, those cracks might just dissapear. :)
  10. Keith Guitars

    Keith Guitars Supporting Member

    Aug 25, 2004
    Woodstock, NY
    Builder: Martin Keith Guitars, Veillette Guitars
    Honestly, they look like end checking to me....

    Moisture-related end-checking, in my (limited!) experience
    often runs at 90 degrees to the grain...I have several heartbreakingly pretty pieces of wood with big cracks in them that I could use as examples.

    Because they are so tight (which is also quite possible...end checking doesn't have to be "open" cracks), I would suggest pretreating before the finish with penetrating epoxy or thin CA.

    There is a water-thin epoxy used for furniture restoration which makes a great base coat prior to finishing - MTD does this as a matter of course.

    CA would work, but it would be messy and smelly to do the whole bass...and a spot treatment might leave...well..spots.

    Given where they are in the body, I don't think they're anything to worry about.

  11. FBB Custom

    FBB Custom TalkBass Pro Commercial User

    Jan 26, 2002
    Owner: FBB Bass Works
    Okay - I'm editing my post here as I just found out from the source that what we see here is for sure not end or surface checks.

    About all that I can add is that I have seen this type of feature in wood. You can't see them until you cut through them and into your body shape. They appear as scratches only you can't generally sand them out so easily. Sometimes you have to cut back a bit to really get them out of sight. The good news is that they are generally benign in the sense that they do not open up in service -- a quick blast with thin CA glue or CPES is a good idea but I think you will be okay living with these things.

    If I'm not mistaken, you'll be the owner of this bass. If I were in your shoes, I might get out the random orbital and see if it goes away easily. If not, I would give it the CA and refinish, and then enjoy the bass.

    Building great basses is about incrementally learning about the process and the materials, one bass, and one surprise at a time. With this bass, you'll see what becomes of these things as they age. With the next bass, you'll see them way before you apply finish and will be able to erase them ahead of time.