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Precision Bass Refinishing question

Discussion in 'Luthier's Corner' started by beyondat, Mar 10, 2016.


  1. beyondat

    beyondat

    Jan 13, 2008
    Bronx, New York
    Hey,
    I just heat gunned the finish off of what I believe to be a 2007 American pbass. I didn't like the Olympic white. Being that I've refinished a mexi bass before I noticed that the finish didn't come off in big hard chunks like the poly finish did. It basically peeled off and was really thin as if there wasn't even a clear coat on top. Is this how lacquer reacts to a heat gun?

    Anyway, I was able to heat gun the hard sealer coat(Fullerplast?) off very easily, it basically turns to powder when heated. After I got it to the bare wood I sanded and added a poly sealer coat not thinking that I just ordered spray cans from Stewmac which are lacquer for a sunburst finish. Does anyone think that I will have any issues using poly/lacquer paint/poly clear coat? Or should I just start over? I wanted to use a poly clear because lacquer takes so long to cure.
    Thanks for any help.
     
  2. earlysecond

    earlysecond In Memoriam

    Jan 26, 2016
    In my experience, which is auto refinishing, lacquer dissolves/lifts polyurethane (acetone solvent). Wait for people witn specific experience to weigh in. You could test a very small spot. Others will likely know better.
     
  3. praisegig

    praisegig Supporting Member

    Jul 7, 2008
    Stephenville, TX
    I wouldn't mix different products in finishing, as a rule. That being said, you can mist the first 2-3 coats of nitro over cured poly and then start the wet coats. I wouldn't shoot poly over nitro, because nitro continues to gases off and start delamination. IME, it can be done.

    Question is, why would I go through the motions and run into problems down the road, in mixing products. Stay with a time tested finishing schedule and products
     
  4. beyondat

    beyondat

    Jan 13, 2008
    Bronx, New York
    Thanks for the responses.
    Question, when you buy a mim sunburst bass how exactly are they finished? Isn't it lacquer sunburst toner with a polyurethane clear coat?
     
  5. earlysecond

    earlysecond In Memoriam

    Jan 26, 2016
    Agian not saying i do it right but its working. Im using water soluable dyes in denatured alcohol, directly on the wood. Then i apply solvent based polyurethane auto clear coat. Then any mid coats like pearls in a special polyurethane intercoat which is clear. Finally more clear to sand then buff. Typically there is no cross linking (chemical bonding) between laquer based and tru poly which is acetone based. This makes, at best, adhesion issues!
     
  6. praisegig

    praisegig Supporting Member

    Jul 7, 2008
    Stephenville, TX
    Fender used a polyester sealer that is a different animal than store bought oil based polyurethane. Not really sure about their clear now other thin nitro, but I think it may be a catalyzed polyester clear or UV cured poly

    I use 2 part urethane over dye colors and acrylic lacquer colors
     
  7. earlysecond

    earlysecond In Memoriam

    Jan 26, 2016
    Not sure that my experience translates exactly. . . .Once I painted a car with lacquer primer, sanded it put acrylic enamel base coat on it then cleared it with 2 part catylized polyurethane clear coat. I eventually stripped the entire car back to bare metal and started over with epoxy primer, which was the best choice. Don't get me wrong, the paint stayed on and looked pretty dang good for 7 years BUT it had a huge bubble of lacquer gas and it began to separate on the hood. Because the 2 components were not compatible, I was able to strip the entire car with a razor blade between the lacquer primer and the epoxy sealer EXCEPT for where there were a couple of bare metal spots where I sanded through the lacquer primer to bare metal then I had to sand it off with 80 grit.

    If you have cured epoxy primer and spray lacquer based paint or primer over it, the epoxy (which is a great first step on bare metal and wood too IMO) it will lift off in sheets after it bubbles.

    Bottom line, I try to avoid mixing types of paint products. Sometimes the results are not good. SO FAR, I have gotten away with polyurethane clear coat (2 part auto clear) over all of my water soluble dyes which have been dissolved in alcohol. No adhesion problems. Not sure if anybody sells entire systems of products from dyes to colors to topcoats in a spray can that they will advertise as completely compatible. I am sure other get away with all kinds of stuff. I do too sometimes BUT unless and until you know how crazy you can get you risk having to strip and re-spray then entire project.

    Hope that helps in any way. I am confident that there are advertised compatible products in an entire refinish system. You will pay more but it could be worth it. Good Luck!
    Brent
     
  8. beyondat

    beyondat

    Jan 13, 2008
    Bronx, New York
    @earlysecond .. as i read this I walk into my house to see that fedex has delivered my stewmac lacquer toner cans! I really wanted to spray my sunburst tomorrow.
    I do have a can of shellac which i could use as a sealer coat under the stewmac toner. Good idea?
    If so, would i have to sand off all of the polyurethane?
    Thanks again
     
  9. praisegig

    praisegig Supporting Member

    Jul 7, 2008
    Stephenville, TX
    You can use shellac as a sealer between the poly and shoot the nitro colors over the shellac. What brand of shellac? Dewaxed shellac is the one of choice for use with lacquer.

    I would suggest in level sanding the poly with 320, shoot 2 coats of shellac, level sand to 400 to a satin sheen with no shiny spots, then the toner. Remember, shellac will impart a slight amber tint that may play somewhat with your sunburst color shades
     
  10. kekani

    kekani

    May 13, 2015
    Kapolei
    With what you have, and plan to use - shellac first, lacquer next. This will grab to the shellac.
    Shellac on top of the lacquer (as a seal coat) - don't sand through obviously. Top coat with poly.

    Would I do this, or even recommend this? No. I'd lacquer a top coat.

    And it's not the lacquer that's going to take a long time to cure, it's the shellac that will remain relatively soft, compared to the other finishes - which you'd be mixing not 2, but three. And you'd do it just for compatibility between finishes, rather than just using compatible finishes.

    If you think about what you said - using poly clear over lacquer because lacquer takes so long to cure - doesn't makes sense putting poly as a top. The lacquer will take longer to cure if you topcoat too soon, and may continue to shrink back under the poly, depending on the lacquer.

    Different ways to do a burst. My comfort zone is tinting the lacquer, although I have stained wood in some projects.
     
    Last edited: Mar 13, 2016
  11. beyondat

    beyondat

    Jan 13, 2008
    Bronx, New York
    Thanks for all the good info everyone. Although it went against my better judgement I went ahead and tried to spray lacquer over the poly sealer and i got a few gooey spots. I ended removing the paint and starting all over.

    This time I heeded the words of wisdom and used shellac as my sealer and everything turned out great! Im just going to stick with lacquer for the clear coat. I'm proud of my first sunburst. Thanks again.
     

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