Best way to remove old Varnish

Discussion in 'Restoration & Repair' started by gborelli, Jul 17, 2013.

  1. gborelli

    gborelli Active Member

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    Hi,

    I have just purchased a damage Martin Sigma guitar with a really sun damaged finish among other things. I need to remove the all the varnish from the guitar and I don't really feel good about using anything that is really harsh, like Jasco as an example. Is there anything that anyone would recommend for this that would be the better way to not harm the veneer on the guitar? The attached picture, I think, probably shows the battle I am about to wage.

    Thanks for any help,

    Gary
     

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  2. Adam

    Adam Well-Known Member

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    Acetone should work just fine.
     
  3. gborelli

    gborelli Active Member

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    Hi Adam,

    So just rub on the acetone and rub off the varnish or do I need to let it set for a bit?

    Thanks for responding,

    Gary
     
  4. gborelli

    gborelli Active Member

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    I don't what the heck they put on this sigma i am trying to strip, but, Acetone just bounced off of it like it was plain water, I tried Jasco, a very strong stripper and it barely did much more than remove the dust on the top of the finish. i am out of ideas other than sanding it off, but, since the Martin Sigma is a veneered wood, I am afraid of going to far and taking off too much. Anyone with any other ideas of how to strip this beast?
     
  5. Adam

    Adam Well-Known Member

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    It's probably a polyester or something equally as nasty then. I had Googled and a wiki entry on them said they were lacquer but a lot of people just generalize clear finishes as lacquer... Aircraft stripper might be your only hope...
     
  6. gborelli

    gborelli Active Member

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    Yeah I thought about that. Nasty stuff.....

    Thanks
     
  7. jkes01

    jkes01 Active Member

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    I would try and wetsand a spot with like 500 grit to see if the faded area clears up. You might try a heat gun, just have to be really careful. Also a cabinet scraper might work. It may take a combination of sand, scrape, heat, and aircraft stripper to remove it.

    The last option it to paint it black :cool:

    -John
     
  8. gborelli

    gborelli Active Member

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    Hi John,

    I really really don't want to paint it black. LOL There is a color wash under the clear coating and I want to try and get rid of that too to bring the guitar to an all natural Mahogany finish. I think the heat gun is going to end up the only alternative and that scares the crap out of me since these guitars are a veneered wood. I was thinking of taking it to a furniture refinisher and see if the had something to remove the finish. Some times they just plan dunk the furniture in a solution, but, that being said I would probably need to remove the fret board first. Geeze - didn't this part of the process was going to be this much of a problem.
     
  9. jkes01

    jkes01 Active Member

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    Yeah, black is a last resort.

    Not sure about dipping an acoustic with all of the unprotected wood inside, not to mention what the solution might do to the glue joints. I would use aircraft stripper before dunking in a bath. Just get some good rubber gloves, a respirator, and some goggles. Work small areas at a time with either a bondo spreader or old credit card. I would try and stay away from a metal putty knife as it is more likely to gouge the wood.

    I am just curious if the oxidation is only on the outler layer of the clear coat. If so, you might be able to wet sand it off and polish it without stripping it completely. Might save a lot of trouble. :thumb:


    -John
     
  10. TKOjams

    TKOjams Well-Known Member

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    you might have to bite the bullet and sand it off, John.
     
  11. gborelli

    gborelli Active Member

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    The damage is deeper than the top coat. The damage is sunbaked damage which I think might be the reason it is to darn hard. I think you guys are right. I am going to need to sand it off. The top for sure. I haven't tried anything on the back or sides, but, if the sanding works then sanding it will be. I came to the same conclusion about dipping it. Not a good idea at all. Bullet biting it will be. Oops. Am I shooting off my mouth again? LOL ( I know, bad pun, but.... )

    G
     
  12. gborelli

    gborelli Active Member

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    Well going to start sanding this beast this weekend. Will post pictures as I go. If anyone drives by and see's a pile of sawdust with a rope hanging out, for God's pull me out!!!
     
  13. gborelli

    gborelli Active Member

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    Just sat down to write a song about this, but, every word in it is sand....
     
  14. TKOjams

    TKOjams Well-Known Member

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    So, how's it lookin'?

    Sorry bout the wrong name thing.:erk:
     
  15. gborelli

    gborelli Active Member

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    Not going yet. Starting later this morning. Man, I have never seen a finish this hard. It was obviously baked in the sun. I think it might be bullet proof. LOL.... I did a test sanding using 220 grit sand paper and it filled the pores almost instantly. We'll see.....
     
  16. gborelli

    gborelli Active Member

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    It was an interesting morning trying to work with this little Sigma. I don't know what Martin told the Korean's to use for finish coating, but, this stuff is bullet proof..... I used a 60 grit paper and a hand sander and after two hours of sanding ( pic on the left ) that is what I had. Oh that also includes trying to use Jasco again, figuring I had broken the seal of the varnish from hell and it would work. It didn't! when I cleaned the surface I came to a realization that the surface I was looking at was just the way they must have done the lamination and that I could sand until there was nothing left and it probably wouldn't make any difference. So, I pulled on my memories of years gone by when I used to sell furniture and remembered some of the tricks the finishing guys used to do. I cleaned the surface with mineral spirits and then painted on some mahogany stain. Let it get almost totally dry and rubbed what little excess there was off. This is only step one of this process. Tomorrow I will sand it again using 400 grit paper and apply more stain and even out the blend so the light spots blend in. Will supply pics tomorrow of step 2. If this works out like I think it will, I will progress to the front, sides and neck using the same process. After that I "think" I am probably going to use a gloss Verathane rather than a varnish. Suggestions welcome.....
     

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    Last edited: Aug 4, 2013
  17. jkes01

    jkes01 Active Member

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    Was the back faded too?
     
  18. gborelli

    gborelli Active Member

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    Yes and no. The back had color, but, the clear finish was blistered so I had no choice but to try to remove it. And it doesn't want to be removed. the underside of the neck and the sides are the same way. The finish is blistered and sun damaged. Honestly, had the description included how bad the finish really was, I wouldn't have bought the guitar. Half of the braces are not glued down on one side or the other. There are about 4 cleats that came unglued that i need to re-glue. The bridge was pulled off and lifted the veneer underneath it and tonight I am going to glue it back down so I sand it, re-stain and varnish or Verathane it before I re-install the bridge and saddle. The tuners need a little work and hopefully that will do the trick. I am pondering if it would be worth adding a Piezo and equalizer to it. My goal now is to re-sell it after I get it restored and I am not sure if it is worth the extra time and expense to put one in. After all that freakin sanding today, hitting it with the stain and seeing it take was extremely encouraging. Worst case is I chalk it up as a training exercise if I can't make it worth something. I only paid $58 for it, so, no big loss except pride. LOL
     
  19. gborelli

    gborelli Active Member

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    Next step set up tonight. Had to glue the veneer back down, I hope, gulp. Pictures pretty well say it all. We will see what the morrow brings..
     

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  20. gborelli

    gborelli Active Member

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    Here are some pics of what it looked like out of the box. Sweet, Right? And these pictures look way better than the real deal.
    See next message.
     

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