Blemishes on old Mando

Discussion in 'Finely Finished' started by WrayGun, Jan 15, 2020.

  1. WrayGun

    WrayGun Tele-Afflicted

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    A friend asked me to make his old Harmony mandolin playable and pretty again. Playable shouldn’t be a problem, but there are some blemishes on the top, partially underneath the pickguard. See photos below.

    My friend suggested using some “Goo-Gone” or something similar to remove these marks, but I don’t think that’s the solution. They just don’t look to me like that kind of substance. Looking more like the lacquer has been affected somehow.

    Anyway, any thoughts/prayers, or advice is appreciated!

    [​IMG][​IMG][​IMG][​IMG]


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  2. Danb541

    Danb541 Tele-Meister

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    Paint thinner (mineral spirits) might clean that up. Prob have to let it soak for a minute.

    Don't use Lacquer thinner, it's too hot, might damage the finish.
     
  3. cyclopean

    cyclopean Friend of Leo's

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    just play the damn thing.
     
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  4. Uncle Butch

    Uncle Butch Tele-Meister

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    Goo Gone might work unless the adhesive ate down into the finish.
     
  5. MarkieMark

    MarkieMark Tele-Holic

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    Depends on what the finish is. I've had goo-gone (and similar) leave an "oily" soaked in spot that will likely never hide.
    i'd try a little mineral spirit soaked rag corner on the least conspicuous edge or spot to see if the defect softens any. But if the finish is porous you may find its difficult to remove without making matters worse.
    It looks a bit like when someone leaves a "song list" taped to an instrument for....years. If the material is hard, and the instrument is old, you may not be able to get that off without needing to refinish the top entirely. Which again, depending on the finish may not be a simple chore.
     
  6. Hiker

    Hiker Poster Extraordinaire

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    My mando has a Nitro finish. You may be dealing with a similar top! It looks like tape, or adhesive was used in the area where a pickguard would be located.

    A dry cloth is the thing for nitro finishes. Some guitar polishes are mentioned in nitro threads.
     
    Last edited: Jan 15, 2020
  7. Freeman Keller

    Freeman Keller Friend of Leo's

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    It is really hard to make old finish damage look good better - if you have to ask what to do you probably should do anything. Naphtha is the only solvent that I ever use on finished instruments, particularly when I don't know what the finish is (lacquer in this case?). What ever you do, don't try to remove any finish or apply more - that 'burst looks like an old hand applied one done in the traditional way.

    ps - naphtha is usually "safe" for nitro but test on a spot where it doesn't show like under a tuner.
     
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  8. WrayGun

    WrayGun Tele-Afflicted

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    Tried some naptha; nada. I’m not convinced it’s dried adhesive goop. Maybe something that contacted and reacted with the lacquer. We may never know. Thanks for all the replies!


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  9. Vizcaster

    Vizcaster Poster Extraordinaire

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    In order to protect against any further damage, is there any issue with the pickguard disintegrating? Sometimes cellulose plastic degrades and once it gets the pox it's a goner (in fact the gases will degrade other plastic parts inside the same instrument case, so the tuner buttons, binding, and even the fret markers may be in jeopardy, not just the areas where it may be close to the lacquer).

    My first thought is that it could've been damage from a vinyl guitar strap. Plasticizer (solvent) leaches out from the strap and eats the finish. but you mentioned it's under the pickguard.

    A spot repair would probably be quite involved and there are "no guarantees" (buzz word for "it's not going to end well."). Theoretically the process would start with butyl cellusolve or lacquer retarder to try to re-flow the finish, then some spot repair of a topcoat, followed by a very long time to shrink back, and buffing out. But if Freeman wouldn't attempt it I wouldn't either. Especially under the pickguard.
     
  10. WrayGun

    WrayGun Tele-Afflicted

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    Thanks. To be clear, it’s just below the guard, not directly underneath it. None of the other plastic or cellulose parts are breaking down (yet).


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  11. mfguitar

    mfguitar Tele-Holic

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    If it was mine I would have to attempt a finish repair that may or may not turn out OK. It looks like someone has already took some abrasive to it. At least I would have a smooth finish when done. I would first try a small area with furniture re-finisher (like a Forby that they don't make any more) with some steel wool substitute. If that does not work I would start with fine sandpaper then use die stain to get as close as I could to the burst finish. Good luck!
     
  12. Intubator

    Intubator Tele-Meister

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    Sounds like a professional instrument restorer is in order. May be an easy fix, maybe not...
     
  13. Freeman Keller

    Freeman Keller Friend of Leo's

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    In my humble experience, mucking with finishes just makes them worse. If its a valuable vintage instrument refins and touch ups cut the value, dramatically. I generally don't try to "fix" finish issues, when I do I have a long discussion with the owner. I would say if naphtha didn't touch it I would leave it.
     
  14. WrayGun

    WrayGun Tele-Afflicted

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    Thanks all. It’s not a valuable instrument (I don’t think), but I still don’t want to wind up making it worse. If it was hidden by the pickguard I would be tempted to try more drastic measures, but for now, I’ll just let it be :)


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