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Veneer discoloration finishing Issue...

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  • Veneer discoloration finishing Issue...

    I noticed a problem with the veneer on one of the pair of small subwoofers I'm working on.

    This is reconstituted striped ebony veneer, and I think I remember there being some creased or slightly damaged areas on the back of the veneer in a few places.
    The face of the veneer itself looked fine before applying, but the backing appeared to be bent or creased to some degree. It looks like some of the glue I used to adhere it to the cabinets (Heatlock) may have bled through the backing into the veneer and was absorbed by the wood portion of the veneer.

    The pics are of the affected areas of the cabinet after applying some Boiled Linseed Oil. I didn't notice it before applying the BLO as there was no contrast yet.

    I'm thinking the oil based material didn't absorb or soak into the light areas which is where the wood absorbed the glue.

    So, now I know to check the veneer backing more carefully before I pick a piece of veneer to apply to a cabinet... Yet another lesson learned.

    But how would I proceed to deal with this? My first thought was to get out some dark oil based stain and sort of 'paint by hand' some darker grained areas to approximate the grain lines. I'd have to be careful with that, probably use a very fine paint brush and take my time. Given the random nature of the grain patterns in this veneer, I have confidence I could pull this type of fix off successfully. I have scraps to practice on first of course.

    Alternatively, I wonder how this will look if I do nothing and proceed. Would it darken up any and appear less pronounced after the seal coat is applied since that seal coat may adhere to it, being shellac based? I can't really duplicate this issue at this point so I can't test for this.

    I plan to apply shellac seal coat after this followed by Crystalac grain filler, etc. by the way.

    Thanks for any ideas,
    Attached Files
    *Veneering curves, seams, using heat-lock iron on method *Trimming veneer & tips *Curved Sides glue-up video
    *Part 2 *Gluing multiple curved laminations of HDF *Cello's Speaker Project Page

    *Building the "Micro-B 2.1 Plate Amplifier -- Part 1 * Part 2 * Part 3 * Part 4 * * Part 5 'Review' * -- Assembly Instructions PDF

  • #2
    I feel your pain. We have a local guy who does faux finishes and repairs on 'real'.
    He says go fast, not slow, or it will look patchy.
    Then use a little tint in a transparent finish so that light is reflected from the smooth top layer.(and if you don't mind a little darker, a bunch of nearly transparent layers like a candyapple finish)
    It's a magic trick, misdirection, you focus on the top(ooh,shiny!)


    • #3
      Yes, painting it in is the way to go. I also will block sand after a few coats of finish to make sure there are no noticeable reflections. I also tend to go darker shades as I think it's less noticeable.
      John H

      Synergy Horn, SLS-85, BMR-3L, Mini-TL, BR-2, Titan OB, B452, Udique, Vultus, Latus1, Seriatim, Aperivox,Pencil Tower


      • #5
        My first thought is to remove the damaged portion by heat-and-scrape method and splice in some replacement veneer. It should splice invisibly, considering the grain pattern.

        My second thought is to try some very careful sanding to remove the impurity from the surface in the affected areas. This would be more time-consuming, but you might prefer it over replacement. If effective, it would be a more perfect match to the original veneer shades. If you are considering the Careful Painting approach, then the Careful Sanding approach might be worth at least a small test. You can check for effectiveness by wiping the newly sanded area with Mineral Spirits - this should give you an immediate look at how it will appear once the finish has been applied and reveal whether or not the impurity (glue or whatever) has been removed effectively.

        In the future, you can always check for glue squeeze out or other impurities which would interfere with finish or stain absorption by wiping it with Mineral Spirits.
        Last edited by PassingInterest; 01-17-2018, 06:28 PM. Reason: Typo


        • #6
          Hi Tom,

          I feel your pain, but in a much diminished way since I have had similar problems but on a much smaller scale since I'm a beginner and have done nothing that remotely approximates the beautiful speakers you build. However, as a clinical psychologist , I can say that to the degree that you are able to re-frame the problem as a valuable learning experience and your work to correct it a useful lesson to fellow forum members, you are growing as a master builder.



          • #7
            Hi Tom,
            ​I had the same thing happen. What you will probably find is that the glue has effectively sealed the wood and it will not absorb any oil based stain. You could try sanding, but that did not work for me as veneer is so thin the glue was all the way through it. You'll probably need to use some sort of laquer based paint that will coat the surface rather that relying on penetration. I ended up using a gel based stain over the whole project and it turned out pretty decent. If you go that route, check out the gel stains from General Finishes, good stuff.

            Best of luck,