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purpleheart refinishing question

Discussion in 'Hardware, Setup & Repair [BG]' started by Davo737, Sep 1, 2001.


  1. Davo737

    Davo737

    Feb 29, 2000
    Syracuse, NY
    Hello all,

    I recently acquired a modulus quantum 5 with a purpleheart top that has been refinished with satin tung oil. Is it a possibility to have any sort of polyurethane or lacquer finish put back on the bass, or has the use of oil rendered that an impossibility? Thanks for the help.

    Davo
     
  2. embellisher

    embellisher Holy Ghost filled Bass Player Supporting Member

    Davo, I don't know the answer, but the guys in Setup are pretty good with finish questions.
     
  3. steinbergerxp2

    steinbergerxp2 Guest

    Jul 11, 2001
    Possible? Yes.

    Cost effective? That's your call.

    Back in WWI the rifle stocks we boiled in a Linseed oil bath for a few hours, and folks were later able to recover them to bare wood using a product called "Japan Drier" from paint stores (rubbing a paste (no doubt caustic) into the wood and scraping it off when it dried, removing oil with it).

    My suggestion would be to ask Modulus what they would want to refinish it. If you sent them a stripped body it might not be too bad. What was described as "Tung Oil" might be something else, and it may be shallow surface coat anyway. If you could find out exactly what product was used, a local refinish shop could give you a quote.
     
  4. Here's the problem with your question - Purpleheart is a naturally oily wood. In most cases where it is used, only an oil finish is applied as that sort works with the characteristics of the wood itself. Since polymerized tung oil soaks into the wood the oils in the grain don't affect it. To put a gloss finish on the wood would require removing the natural oils, at least temporarily, so that a topcoat can be applied and dry before the oils leach to the surface again. This CAN be done using acetone but I'm skeptical about the quality of the results. Since purpleheart has such magnificent coloring, I would be afraid of the wood changing color. This might not happen or it might reverse itself when the topcoat is applied but that's where I'd be concerned.

    As an alternative, why not use the wood and it's current finish exactly as is to get a look more in line with your tastes? By that I mean that you can polish the purpleheart and the oil finish to the point of a near gloss sheen and then use a carnauba wax to put even more of a gloss on it. At least this way, the question of how well a glossy coating takes takes to the surface isn't even asked and the results will be controllable and very nice indeed.
     
  5. Davo737

    Davo737

    Feb 29, 2000
    Syracuse, NY
    Thanks Steinbergerxp2 and Hambone for the replies,

    There are basically two reasons why I had intended to refinish the bass. First, there are still traces of the original polyurethane finish around the pickups and knobs. Second, the bass has a thumbrest that I would like to remove, and there is a bit of discoloration underneath. Its not that I don't like the looks of the oil finish, because I certainly do, but I wonder if that will be enough to protect the wood. I assume so, so long as its properly cared for.

    Hambone, I completely agree - I absolutely love the color of the purpleheart and certainly would not want to do anything to jeopardize that. I believe I'll give it a go with re-applying the oil, and then obtaining a glossier finish with some good old fashioned polishing. By the way, would anyone have any suggestions as how to best remove the remaining traces of polyurethane?

    Thanks again.

    Davo
     
  6. bassmonkeee

    bassmonkeee

    Sep 13, 2000
    Decatur, GA
    My Curbow 5 string has a Purpleheart back, and a gloss finish. Just for the record. But, I agree with Hammy on this one--if it ain't broken, blah, blah, blah.:D
     
  7. Davo, I would remove the pots and try scraping the surface to remove the last of the poly. You can use a glass slide - you know, from biology class:) or a box cutting knife blade held so that the blade slopes away from the direction of travel. Doing this will only peel the poly and not scratch the wood. As a matter of fact, this process is precisely the technique used by some of the top luthiers to get a glassy finish on their wood before staining and topcoating. It's called "micro-planing" and really works. You might even use it on all of the flat surfaces to even them out before you start re-oiling.

    A note about polymerized tung oil: for the best finish be prepared to put on at least 6-8 coats with drying time inbetween. Apply the oil with high quality 0000 steel wool and rub it into the grain keeping the pad wet. As you go, the oil will begin to "stiffen" and drag. That's what you want. When you've covered the whole body like this - until the oil thickens - stop, wipe the excess off until the body is smooth and let this dry at least a day. Repeat the steps until you can't stand it any longer ;) Then let the bass dry for several days. I use my nose to tell me when it's dry enough - If I can't smell it then all of the aromatics have evaporated and it's time for final polishing. Don't use anything but a very soft cloth for this step. Rub hard, even until you feel a little heat. This will begin to really bring up the shine. Then let it set a few hours and apply a good carnauba wax to the body. Keep applying until you get the sheen that you want. The results will be very resistant to all of the normal encounters the bass will see. If you do get a scratch in the surface, you can just polish it out with the wax.

    Step back and admire your work - others will too!
     
  8. Davo737

    Davo737

    Feb 29, 2000
    Syracuse, NY
    Hambone,

    I followed your advice, and the bass looks phenomenal. I never would have expected the results that I got! Thank you.

    Regards,
    Davo
     
  9. It worked?? REALLY??;)


    Seriously, I'm glad I could help. Now, for continued good looks, just rewax/buff if the finish gets to looking a little dull. The wax will be protecting the oil finish so there isn't any need to add more to keep things polished. If you get a scratch through the finish, you can smooth it with a scotchbrite pad then dab a bit of oil on and it should disappear for the most part.

    Enjoy!!
     
  10. Davo737

    Davo737

    Feb 29, 2000
    Syracuse, NY
    Hambone,

    If I could trouble you with one more question: I noticed that there are little white specs done in the grain on some areas left over from the waxing that I can't seem to get out? Is there anything that can be done about that that doesn't involve re-doing the entire thing? Thanks again.

    Davo
     
  11. I think that the specks might be a little bit of buildup of raw wax in the porous parts of the grain. That isn't a problem I've encountered before so my approach is untested but it should work:

    Get out your polishing rag - the one you applied the wax with. Also get out a hairdryer. What you've got to do is literally melt the wax out of the grain and smooth it out. Gently heat the area with the hairdryer and then smooth out the wax buildup. It might even be that when you heat the wax, it'll disappear as it turns molten. That's good cuz that'll be your gauge to know when you've heated it enough. Just wipe out the grain and buff. You sure don't need to cook the body!

    To avoid this in the future, you might want to heat your wax as you apply it. Some guys just put the can on a hotplate and warm it until it melts, then dip and apply the warm goo.

    Hope this helps!

    Oh yeah, any chance we'll get to see this beaut??
     
  12. Davo737

    Davo737

    Feb 29, 2000
    Syracuse, NY
    Hambone,

    Once again, thanks for the advice. I'll give it a shot this weekend and let you know how it turns out. Oh, and I'll try to get some pics up.

    Regards,

    Davo
     
  13. Davo737

    Davo737

    Feb 29, 2000
    Syracuse, NY
    Hambone,

    I have a follow-up question for you. Although I love the look of the tung oil finish, the feel of it is rather unpleasant. That is, where my forearm rests over the top of the bass, it is quite tacky and sticks to my arm. I've buffed and waxed it numerous times over, and can't seem to fix the problem. Any suggestions? Once again, thanks for all the help.

    Regards,
    Davo
     
  14. Hmmm:confused:

    The only thing I can imagine is that the area hasn't cured well from the last coat of oil. Final curing should be when you can't smell the tung oil anymore and then I would wait another day or so. Perhaps you could strip the wax and then see if you uncover an oil scent. If you do then I would finish stripping the wax and let the body cure for several days in a dry evironment. I'm under the impression that polymerized tung oil is more resistant to body oils so I don't think that is the problem though it might be an aggravating factor.
     

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