THICK finishes for Electric Guitars

Discussion in 'Luthier's Guitar & Bass Technical Discussion' started by Hammers and chords, Nov 19, 2019.

  1. Hammers and chords

    Hammers and chords Supporting Member

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    Hi everyone... I've modified a bunch of guitars in the past with stickers/beer labels and finished over them with poly but that tends to yellow (and take a LONG time to finish with all the coats). I was planning on trying to finish a few flattops with a two-part epoxy but I'm finding that the edges are not flush and the finish wants to LIFT off the stickers and ultimately come off.

    Any suggestions on what finish materials I could try for better results? The conditions here are getting cold so the varnish finishes might be tough to try but I'm game. Thoughts? I can send a link to what I'm finishing if you want to see.

    Here is a picture of one of the projects:

    [​IMG]

    [​IMG]
     
  2. KGWagner

    KGWagner Member

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    Sounds like the adhesive on the stickers is being attacked by the solvents in your finishing material. Usually, shellac is a good barrier finish, but I'd be concerned with yellowing there, and since it wants to be reduced with alcohol, you'd want to experiment with your labels/stickers to see if they're sensitive to it.
     
    B. Howard likes this.
  3. B. Howard

    B. Howard Silver Supporting Member

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    As noted the weak link is the adhesive on the stickers and it will always be a potential problem no matter what finish you use.
     
  4. whoismarykelly

    whoismarykelly Oh look! This is a thing I can change!

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    You may get slightly better results if the finish you use has some regular guitar finish at the edge to adhere to so you don't have the sticker layer between the final finish and the guitar at that spot. Say you leave 1/8" or more of faux binding look around the edge you may get better adhesion there have less likelihood that the whole thick finish layer wants to lift off. You could probably make this area after you do your layout by just running a razor blade around the top with a little depth stop on it and then removing the outer 'rim' of sticker and scuffing up that edge finish.
     
  5. Hammers and chords

    Hammers and chords Supporting Member

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    Thanks everyone. The weak link isn't the adhesive of the stickers. The stickers are not coming off. The epoxy is not fully bonding with the stickers (top). Meaning, the stickers are on the guitar body as shown above, and when the epoxy cures it looks perfect, but all I have to do it pull up one edge of the epoxy and the entire finish lifts off the stickers.
     
  6. Hammers and chords

    Hammers and chords Supporting Member

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    Yes, I think you may be right. I might have the epoxy finish run on the edge of the guitar so it can adhere to that guitar and not just to the stickers.
     
  7. B. Howard

    B. Howard Silver Supporting Member

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    Ah.... so that is being caused by lack of tooth for thew finish to grab onto. That is why you must sand wood or metal to get paint to stick, it needs a mechanical anchor. The stickers surface is too smooth for the finish, even an epoxy, to grab onto. A coat of shellac may fix this but I doubt anything will work long term.
     
  8. ahhlou

    ahhlou Member

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    Have you tried lightly scuffing the stickers with 600 grit before applying the finish? You can test this on some spare stickers.

    Another idea is to use cyanoacrylate (crazy) glue as finish. Again test the technique on a wood block with a spare sticker...
     
  9. T Dizz

    T Dizz Member

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    This^ You'd need something that permiates the stickers if you want top notch results. Even then it's a crap shoot.
     
  10. onemoretime

    onemoretime Member

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    Try Duplicolor DP199 Adhesion Promoter for your sealer followed by any Acrylic Clear you choose. Dupli-Color DA1692 General Purpose Acrylic Enamel is good. Both are available at any auto parts store or Amazon. The 2k Clearcoats are even better, like SprayMax 2k (Amazon) which is aier to lay down smooth and can be wet-sanded and buffed.
     
  11. Hammers and chords

    Hammers and chords Supporting Member

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    Thanks everyone! I will try a few samples and will post results. I've used lacquer and poly and both adhered to the stickers fine, but they yellow (especially the poly) so was looking for an option that didn't yellow. Plus, the epoxy allows me to finish the top or head stock in ONE coat and doesn't require sanding so seemed like a perfect solution. But perhaps a coat or two of something that would bond with the finish FIRST and then try the epoxy over it.
     
  12. JBG

    JBG Member

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    If you're going epoxy, look into West System epoxy. It's very thin (for epoxy), and flows much better than stuff you would normally find in a big-box/hobby store.
     
  13. larry1096

    larry1096 Member

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    Have you considered a clear acrylic 'wrap'? It would at least have the advantage of being easy to remove if you don't like the result.

    Larry
     
  14. Stike

    Stike Member

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    What kind of poly? Automotive urethane/polyurethane clears are usually water clear and non yellowing.
     

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