Will gluing a veneer accent line warp my body blank...

Discussion in 'Luthier's Corner' started by honza992, Apr 7, 2017.

  1. Hi All

    I want to put a black 0.6mm veneer accent line between my ash body and redwood top. The body is already at it's minimum thickness (31mm) so I'd really rather the body didn't warp.

    In the past I had an issue with using Titebond to glue on a 6mm tops (it warped a 40mm ash body) so I changed to using epoxy which has worked fine.

    Should I do the same with the veneer, ie use epoxy? Or am I better using something like Titebond Cold Press?

    Or am I just being paranoid and there's not chance gluing such a think veneer could cause 30mm of ash to warp.

    Cheers all!
  2. Beej


    Feb 10, 2007
    Vancouver Island
    I'd probably just do epoxy if you're already comfortable with it. Doing the same thing, I'd be pressing them all together at once, with plenty of clamping pressure. I've not had warping of the top with that method myself...
  3. Ruckus_Instrmts


    Jan 5, 2010
    To answer your question it helps to understand why you are getting warpage in the first place.
    Different varieties of wood have different rates of expansion and contraction. Therefore, when gluing two different varieties of wood with a water based glue like Titebond(PVA) the grain swells and the glue sets before the grain can return to its lower MC. This induces tension and the result is a warped glue-up from what used to be two flat boards.
    Some woodworkers get around this by gluing a third board to the back of the glue-up (preferably of the same variety as the top). This induces, in theory, the same amount of tension to both sides thus keeping the glue-up flat after drying.

    While there are some "water-based" epoxies the vast majority are petroleum based and do not cause wood to swell the same as compared to PVA glues.

    So long as the veneer and other boards are flat before glue-up it should come out flat after cure.

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