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Thread: Gunk Removal

  1. #1

    Default Gunk Removal

    It's not a mandolin, but hoping someone can suggest how to remove this gunk from vintage archtop. It was left by a previous installed pickup. Any help appreciated.
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  2. #2
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    Default Re: Gunk Removal

    Is the “gunk” adhesive residue? If so, Goo Gone should take care of it, and won’t harm the finish.
    Don

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  3. #3

    Default Re: Gunk Removal

    Naptha, aka Coleman fuel, will do the trick.
    It will not harm the finish one bit.

  4. #4
    Registered User sunburst's Avatar
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    Default Re: Gunk Removal

    Naphtha in lighter fluid (fuel for lighters, like Ronsonol). Coleman fuel is gasoline and might harm the finish.

    For cleaning finishes, start with water (a clean, damp, soft rag). If that doesn't work, try water and a little soap or detergent. If that doesn't work, then try naphtha. If that doesn't work, there is probably finish damage, and buffing, or even sanding and then buffing might be in order.

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  6. #5

    Default Re: Gunk Removal

    Quote Originally Posted by sunburst View Post
    Naphtha in lighter fluid (fuel for lighters, like Ronsonol). Coleman fuel is gasoline and might harm the finish.
    In California you can't legally buy Naptha, but you can buy Coleman fuel and Rosonol which is the same stuff. I've used it to get all kinds of gunk off old acoustics, eg.sticker residue, and it works great, and does not harm the finish at all. I've also used it when I've replaced acoustic pickguards to get the adhesive residue off......works great.

    "Coleman fuel is a petroleum naphtha product marketed by The Coleman Company. Historically called white gas (not white spirit), it is a liquid petroleum fuel (100% light hydrotreated distillate) usually sold in one gallon cans. ... And like gasoline, it should not be used as a substitute for kerosene or diesel fuel."

  7. #6
    Mediocre but OK with that Paul Busman's Avatar
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    Default Re: Gunk Removal

    Quote Originally Posted by Titleist77 View Post
    It's not a mandolin, but hoping someone can suggest how to remove this gunk from vintage archtop. It was left by a previous installed pickup. Any help appreciated.
    Mandolin or not, you could just install a Florida
    For wooden musical fun that doesn't involve strumming, check out:
    www.busmanwhistles.com
    Handcrafted pennywhistles in exotic hardwoods.

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  9. #7
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    Default Re: Gunk Removal

    I`d just try plain old rubbing alcohol if it is due to adhesive residue....

  10. #8
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    Default Re: Gunk Removal

    Alcohol dissolves lacquer!!!! Do not use it!!!

    Unless something has changed, Coleman fuel IS gasoline, not naphtha.

    Naphtha, mineral spirits, or turpentine are all safe. If none of that is still legal in California, whatever they are now selling as paint thinner is probably safe, but test it first to make sure.

  11. #9

    Default Re: Gunk Removal

    Quote Originally Posted by rcc56 View Post
    Unless something has changed, Coleman fuel IS gasoline, not naphtha.
    Sorry..... it's not gasoline.
    http://coleman.custhelp.com/app/answ...-coleman®-fuel

    So something may have changed.
    https://en.wikipedia.org/wiki/Coleman_fuel
    Last edited by oliverkollar; Jan-05-2018 at 8:55pm.

  12. #10
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    Default Re: Gunk Removal

    From the Wikipedia article above: . . . "a flammability similar to gasoline . . ."

    While it may have a lower octane than unleaded gas and less additives, it doesn't sound like something I would want to use as a cleaner in my shop.

    Bottom line, it was formulated as a combustible fuel, not a cleaner. Use at your own risk. There are many safer alternatives.

  13. #11

    Default Re: Gunk Removal

    ......edit

  14. #12
    Registered User Ivan Kelsall's Avatar
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    Default Re: Gunk Removal

    Do you know what the finish is ?. Is it Cellulose lacquer / Varnish ????. You need to know before you try any type of solvent.
    You might try either Naptha / gas.etc. on a tiny area of the guitar where you could quickly wipe it off if any damage was seen to be happening.

    ''Experimenting'' with solvents isn't something to try without a bit more info. on your guitar's finish - IMHO. Also,looking at the surface crazing,would any solvent penetrate down to the wood ??. If that happened,it's a re-finish job. I'd personally use a VERY sharp blade like a scalpel,to VERY carefully,VERY lightly scrape the most contaminated area to see if you could remove the gunk from the surface. If it doesn't come off easily - leave it,or you could improve it worse !,
    Ivan
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  15. #13
    Mediocre but OK with that Paul Busman's Avatar
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    Default Re: Gunk Removal

    I was thinking of scraping too, maybe even with your fingernail.
    For wooden musical fun that doesn't involve strumming, check out:
    www.busmanwhistles.com
    Handcrafted pennywhistles in exotic hardwoods.

  16. #14

    Default Re: Gunk Removal

    Quote Originally Posted by Ivan Kelsall View Post
    \
    ''Experimenting'' with solvents isn't something to try without a bit more info. on your guitar's finish - IMHO. Also,looking at the surface crazing,would any solvent penetrate down to the wood ??. If that happened,it's a re-finish job.
    Ivan
    If it's varnish you should not use any solvents.
    If it's lacquer, naphtha would work well and if it penetrates the crazing, it'll evaporate off, unlike goo gone, which would penetrate and be absorbed by the wood.

  17. #15
    Registered User Frank Ford's Avatar
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    Default Re: Gunk Removal

    Naphtha is usually a decent first choice, but not having specific knowledge or direct access, I'd say you might find success if you try different methods and work very gently. As last resort, I typically do some VERY gentle scraping and polish up the resulting light scraping marks.

  18. #16

    Default Re: Gunk Removal

    Thanks for all the comments. The guitar is a 1940's Gibson L7. It's is real nice shape with exception of this eye sore. I want to make sure whatever I use won't harm the finish. I will try soap/water first and report back.

  19. #17
    Registered User sunburst's Avatar
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    Default Re: Gunk Removal

    We are so familiar with the stuff that we don't think of water as being the nearest thing we have to a "universal solvent". The various things we have around us, the various "junk", "crud", "dirt" and so forth, more of it is water soluble than anything else. To make it even more convenient, it causes little damage to many things when used in moderation. It is always a safe bet on common finishes (with the understanding of moderation being key!), so even if it does no good, it will do no harm and it was worth a try.
    A little detergent or soap added to water and we turn it into something that will dissolve even more types of "junk", "crud", "dirt" and so forth, without making it more dangerous to finishes.
    All that, and in most places, all we have to do to get it is keep the water bill paid! Just seems too simple, doesn't it?

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  21. #18
    Adrian Minarovic
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    Default Re: Gunk Removal

    I would add that on such cracked/crazed finish as in OP it is reasonable to go as dry as possible. perhaps first try would be just dry wipe with microfiber cloth or gentle fingernail scrape (or credit card), then very slightly damp and only after that water with detergent on q tips trying to work in way that doesn't press the gunk into finish cracks.
    Adrian

  22. #19
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    Default Re: Gunk Removal

    A '40's L-7 would have a nitrocellulose lacquer finish that is quite delicate. These finishes often flake or turn to powder if much mechanical action is applied to them. Also, they will peel off if any tape is applied to them.

    If this were to come into my shop, I would carefully use a scraper with most of the blade masked off [see frets.com, razor blade scraping] to try to remove the upper layer of gunk, using as little downward pressure as possible. I would probably mask the blade with electrical tape on this sort of a job. I would then follow with naphtha or mineral spirits rubbed in gently with a fingertip, allowing time for the stuff to soften the gunk as much as possible. It might take a bit of time and patience to soften it up enough to be removed. Then, finish up with more naphtha on a clean, soft cloth, going with the grain, and changing the cloth often as it becomes soiled.

    I'd be a little wary of using water on this one. I've seen these old Gibson finishes react poorly to water. If you do use it, use plenty of detergent, use your fingertip only, and dry the work surface every 30 to 60 seconds or so.

    Once all the gunk is gone, the surface may look quite dull. Wait overnight before using anything to restore the gloss. I would only use a high grade violin polish, and only very sparingly.

    And remember, don't tape an old Gibson finish.

  23. #20

    Default Re: Gunk Removal

    To my eyes, it is very minor, certainly in keeping with a guitar that old. It doesn't bother me. I would try my fingernail first and see if that does anything. It would be very easy to make it worse by creating a shiny spot on an otherwise naturally aged guitar. The missing binding from the pickguard is more of an issue for me -- and one that can be safely and easily touched up. IMHO, you have to know when to stop when trying to deep clean an old instrument.

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