Thinning out a G&L Kiloton body to shave weight

Discussion in 'Luthier's Corner' started by Florijan, Dec 12, 2020.

  1. Florijan


    Mar 29, 2018
    Hi all!

    I have a G&L Kiloton Tribute that weighs 4.67kg (10.3lbs). It hurts... I have a G&L SB-2 Tribute that weighs around 4.2kg, with the same body shape and similar hardware (in terms of weight).

    Ironically, I expected the Kiloton to be lighter then SB-2 because it's basswood, while SB-2 is Mahogany :(

    So, my question is: what do you think about taking the paint off, thinning out (and possibly sculpting) the body a bit, and repainting? I'd try to take the most mass by thinning it out. I think it only makes sense if I take at least 350 grams of. I might then invest in lighter tuners to get another 100ish grams off, for a total of 450 grams.

    Now, if the body weighs around 3kg (is this a reasonable assumption?) and I want to take let's say 400 grams off, that's around 13% off. Let's call it 15%. The body is 42mm thick, without the solid paint that might 40mm (I'm assuming this). So I'd need to take 40mm * 0.15 = 6mm. That seems quite a lot... Considering the neck cavity, PU cavity, PU screws etc... It might just not be feasable...

    Am I thinking in the wrong direction?
  2. Slidlow

    Slidlow Supporting Member

    Apr 15, 2009
    Oshawa, Canada
    If you are going to strip the body. Shave off 3/16 to 1/4", hollow to body out in several places and then install a nice book matched top. The original cavities can be used to guide a router to match the pickup routes, etc.
  3. I looked the model up and assume you have a pick guard.
    Why not route out cavities underneath by drilling out multiple small holes if there’s enough material to do so.
    As an ex-bike racer I can truthfully say that lighter tuners and thinner paint will lighten things up but it won’t make your bass faster. :)
    L Anthony, Florijan and T_Bone_TL like this.
  4. My opinion:

    Sell it and find a lighter one. By the time you Frankenstein this thing, you may or may not get where you want to be weight-wise, and UNLESS this is done in a very professional way (that is, after you're finished, a stranger would have to really stop and think why this one is lighter and/or different as it looks completely stock), you will be hard-pressed to sell it off at any reasonable return.
  5. wraub


    Apr 9, 2004
    ennui, az
    I'd make a lighter copy of the existing body, then store the existing one.

    Or, look for a lighter body for sale, or, only play that bass while seated. ;)
    design, Florijan and jallenbass like this.
  6. Florijan


    Mar 29, 2018
    Great, thanks for your thoughts...

    I also really like doing some woodwork, so I like @Roland GR 88 's reply. I'm aware that I'd be lowering the resell value. But, I already converted it to fretless, so I'm more or less married to it :D And I wasn't able to resell it before the conversion (not much demand in Croatia for a G&L Kiloton). Also, I'm happy with the conversion and the fretless sound I get from it. So, it just might become hollowbody :D
    Ricky Rioli likes this.
  7. Florijan


    Mar 29, 2018
    Oh yeah, making a whole new body might also be a good idea, though technically more demanding.
    wraub likes this.
  8. T_Bone_TL


    Jan 10, 2013
    SW VT
    ...I think the point is, not all that much more demanding, really.
    wraub and Picton like this.
  9. L Anthony

    L Anthony Supporting Member

    May 14, 2009
    There's a certain irony in trying to lighten an instrument with the name of Kiloton...:laugh:
    deff, Ricky Rioli, Joshua and 7 others like this.
  10. +1

  11. Bruce Johnson

    Bruce Johnson Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    What I would do, if it were in my shop:

    Rout 1/4" off the back surface of the body. Lay out and rout some large chambers in the back side of the body. Make 4-5 medium size chambers with 1/4" wide walls between them. Place most of the chambers in the forward part of the body. Rout the chambers deep enough that you are leaving only 1/4" top. Then cut and glue on a 1/4" thick back, out of some medium weight wood. Maybe alder, ash, walnut. That construction arrangement will minimize the weight of the body, while keeping the stiffness about the same. It shouldn't affect the tone much.

    Then you'll have to work with the balance. Lighter tuners if you can, and you may have to add some metal weights at the back end of the body. I'm guessing you might reduce the overall weight by 700g?
    Allegrus, ICM, 2saddleslab and 7 others like this.
  12. Florijan


    Mar 29, 2018
    Thanks for these details. I'm thinking it might be better to do it from the front, so I can put on some nice wood on top. As for the tuners, I was already looking into it, and some people are successfully replacing G&L Tribute tuners with Hipshot Ultralights for around 160 gram reductions. I think that, and the very beefy G&L bridge, and your suggestion to take more material off the front neck-end of the body, might be the way to keep balance.
  13. Start with the tuners, then the bridge. Get a feel for how it balances first, then when you rout the chambers you’ll feel how that balance changes.

    @AphekGreg drilled out small chambers thru the pickup cavities to reduce mass. Worked really well.

    Probably in this thread, around 2019 IIRC.
    Ibanez Musician Bass Club
    Last edited: Dec 13, 2020
  14. Merlo79


    Feb 14, 2014
    Wait, they make heavy basses out of basswood? How? :)
    Ricky Rioli likes this.
  15. Florijan


    Mar 29, 2018
    I was surprised too, based on what I've read about basswood. It's a modern precision-style body... Same body shape in mahogany is 450g lighter :/ Maybe the piece is exactly from a branch-point :D
    Merlo79 and Ricky Rioli like this.
  16. Bruce Johnson

    Bruce Johnson Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    Working from the back is better from an engineering viewpoint. While under load, the back surface is under tension, while the top surface is under compression. Putting the thin cap of stronger wood on the back, means you can cut away more of the center wood without losing strength and stiffness. But I understand that most people want to put a cap on the top for decorative reasons.
    StevieMac, Ricky Rioli and Beej like this.
  17. Merlo79


    Feb 14, 2014
    I know diddly-squat about woods, but I do know no basswood bass I ever tried was anything more than average weight. I'd be really interested in an explanation. Perhaps someone on a luthier subforum knows more.

    I've just quick googled that the average dry weight of mahogany is 40 lbs/ft3, while that of basswood is 26 lbs/ft3.
  18. Florijan


    Mar 29, 2018
    Well, if I get around to doing this project, I will weigh the body alone, with and without paint and report. In the meanwhile, no idea... There is 450g extra, compared to the same-shaped SB-2. SB-2 has the same bridge and tuners. Same neck profiles. Both are passive, Kiloton has a mini-switch extra :D SB-2 has a P/J config, the Kiloton a humbucker, which I don't imagine is (much) heavier than the P/J. SB-2 has a maple/maple neck, Kiloton a maple/rosewood, Kiloton is now fretless. Both are solid-painted. Both balance well, Kiloton is dead-set of course, no dive possible. So, maybe a bit of extra weight in the neck due to density differences, but most of the weight difference really must come from the body... Oh yeah, when I took the neck off, the cavity displayed the light color of basswood (my only reference is online materials), so I think that's inline with the spec.
    Merlo79 likes this.
  19. TomB

    TomB Supporting Member

    Aug 24, 2007
    One detail to add: If you do hollow out, be sure to leave some beef at the strap pin locations. They do exert a lot of stress if you use a strap.
  20. Florijan


    Mar 29, 2018
    Thanks for the tip! I was thinking about it already, but any other such tips are very welcome. I'll probably post a pic of the planned holes once I define the plan :D
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