Finish questions for the more experienced.

Discussion in 'Guitar Building' started by Zeegler, Jul 31, 2015.

  1. Zeegler

    Zeegler Active Member

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    Hey guys, I know there's some of you can answer these questions for me.

    I'm just in the process of finishing 2 guitars. My plan when I started building was to have them finished by someone else, but I simply could not find someone who is local, easy to work with, and reasonably priced. I finally came to the conclusion that I'm just going to have to do it myself.

    I'm using Watco Lacquer, because apparently it is true nitro even though it doesn't say it on the can, and it's the only brand I can get locally without ordering it. I've also heard and read lots of good things about it. Anyone here try it?

    So, I'm getting along quite well, but I'm wondering how many coats I should put down before it's safe to wet sand? Also, would it be a good idea to do a couple of extra coats around any edges, to prevent sanding through it?

    I'm using rattle cans at the moment, but I have a can of "brush on", that can be sprayed if thinned correctly. I also have a HVLP spray gun, but haven't used it yet. Is it a huge difference going from rattle cans to HVLP? I assume the paint will be more finely atomized, and will go on smoother?

    I have more questions about polishing, but I'll hold off on those for now.
     
  2. Zeegler

    Zeegler Active Member

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    Anyone finish a guitar before?

    Bueller?
     
  3. rainH2O

    rainH2O New Member

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    Not an expert by any stretch, but I just sprayed nitro on two guitars. On a first guitar finish, I would go thicker with the clear coat (10-12 coats, three passes to a coat) in order to build in some margin for error the first time you wet sand. I could tell a difference in my ability to judge how I was sanding on the second one, I'm sure with more experience my clear coats can get considerably thinner.

    Also, If you are doing a burst, I would put a couple of coats of clear over your base color before shooting the burst. It makes it much easier to fix a problem. For instance, if you get drops of spatter in the middle of your top, you can gently scrape/wet sand it away without digging into your base color. This saved me from having to completely strip the top on my second one when I made a mess out of one part of the burst.
     
  4. pshupe

    pshupe Member

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    I've only done a few as well. I have sprayed nitro with an HVLP gun and they have turned out quite well. I've never done rattle cans but apparently you have to do more coats with the rattle cans as there is more over spray.

    I concur with rainH2O - 10 - 12 coats, 1 coat being 3 passes. My second last build I sanded through a bit, so I probably put 14-16 coats on my next one. I'm actually just wet sanding that build now. Good luck.

    Cheers Peter.
     
  5. Zeegler

    Zeegler Active Member

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    Wow, that's a lot more than I thought actually. On my first one, I had about 4 coats down, and wet sanded VERY gently. I did end up sanding through in about 3 or 4 spots, but I was able to dab some stain in those spots to eliminate any lighter spots before doing more coats of lacquer. I have another 2 coats on it now, but I guess I should do another 4 coats before wet sanding again in preparation for buffing and polishing.

    I did my burst with just stain on bare wood, so I didn't need to seal the base colour first. I suppose it's easier doing the burst with tinted lacquer over a sealed base coat, and I will hopefully progress to that point when I get around to buying an airbrush.

    I don't know if it's usual with nitro, but the Watco stuff dries very fast.

    Do you guys have different grades of buffing pads going from coarse to smooth, or just one pad and different grades of compound/polish?
     
  6. pshupe

    pshupe Member

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    Some people do sand in between coats. I do not. After the first coat of lacquer I sand with 1000 grit. This is to knock down any raised grain. After that I just build coats until I get enough on then let it sit for 6-8 weeks, or until I cannot smell the off gassing any more. The subsequent coats just melt into the previous, so I am not convinced it is of any real value to sand in between. Possibly if you get a run, but that has happed with me and I just build on top and eventually it melts in.

    Regards Peter.
     
  7. Adam

    Adam Well-Known Member

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    I wouldn't recommend sanding between coats. Sand between days, not coats. Each day is 4-5 nice, not too heavy not too light coats. Sand 320 grit between days, do 3-4 days of lacquer. The way you know it's the final day is when you can sand the guitar completely smooth, no more pores/low spots.

    With the Watco stuff and any rattle can really, let it cure for several months before you try wet sanding and buffing.

    10-12 coats 3 passes each will put a LOT of lacquer on a guitar. When you get more than 10mil of lacquer on a guitar you open up the risk of the lacquer cracking and being brittle. 10mil is NOT a lot of lacquer, it's only .010". When I spray I aim for 5-6mil after buffed.
     
  8. Knarbens

    Knarbens Well-Known Member

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    So that stuff does take more time to cure compared to what you use?
     
  9. Jay Jillard

    Jay Jillard New Member

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    OP, you will very quickly redefine what a 'reasonable rate' is after you get about halfway through a proper lacquer finish =P

    go thicker, stay away from edges with sanding. wait till it's actually cured, don't rush it.
     
  10. B. Howard

    B. Howard New Member

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    Watco is not what you want to use. Way too soft! Number of coats will depend on how much you put down in a coat and the solids content of your material. Knowing your final film thickness is important. Too thin and you'll cut through when you buff. Too thick and it will craze and check in a few years, especially with the modern stuff.

    Good equipment and proper set up and technique are half the battle, prep work is the other.
     

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