Wet sanding, polishing, shielding, and a gouge!

It is advised to wait a month before starting to sand, because that’s how long it takes lacquer to reach its practical hardness. I didn’t have the patience for that, so I started wet sanding after three weeks (as I mentioned in my last post). Here’s what the guitar looked like prior to sanding:

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I started by filling all the holes, with the exception of the neck pocket holes, with beeswax. The wax prevents water from going in them, swell the wood, and therefore make the lacquer above it crack. I held off on buying beeswax because any store that had it had just a tiny bit of it, and it seemed to be really hard to the point where I won’t be able to easily cut it and shape it. The size really isn’t a problem, because I think I can easily do 30 guitars with the small amount of beeswax that I got. As for its hardness, it is indeed hard, but I could cut a small piece with a knife, and then roll it in my fingers to make it fit the holes. I then cut the excess with a ruler or something, but I also discovered that if you sand the excess, it won’t mar the finish or anything. At best it clogged the sandpaper. Unfortunately, some holes weren’t 100% plugged, and water got in them and caused cracks. Next time I’ll use more wax, wipe off the guitar more often, and really just use the water to clean the sand paper. For what it’s worth, though, the cracks were very thin, and I don’t see or notice them anymore.

Besides cracks, I also had to deal with sand throughs. I wrote in one of the last posts that I gave up on spraying clear over black and ended up spraying four coats of black over the five coats of clear I had on the body. I should explain why four. For “thin skin” finishes, it is recommended to spray 9 to 12 coats of clear over the color coats. I already had 5 coats of clear on and a very thick first coat of color, so I thought four (for an overall of 9ish final coats) should keep it thin. I also tested it before spraying and four coats were enough to not sand through. However, I think I started sanding through to the clear coats underneath a little bit. The only indication I have for sanding through is that the water (as I was sanding) wasn’t pure black like it did earlier in the sanding, it was a little diluted. Usually, sanding clear lacquer makes the water turn white, but I didn’t get that far. However, the sand throughs must be minimal, because I can’t see any discrepancies in the finish. Still, next time I’ll put on six final coats or more (if I don’t spray clear).

The sand throughs were a result of how long and hard I had to sand. Sanding took maybe 5-6 hours (if not more) starting with 800 grit all the way through 2000, and I had to press really hard to sand anything. This was probably the result of how long I waited to sand. For instance, the neck of this guitar I sanded five days after I finished spraying, and it required minimal effort to do. Next time I’ll wait five days, then test the lacquer by pressing with my nail at a hidden spot. If there’s no impression, I’ll wet sand, and then let it dry for 20 more days, then rub it with a compound and polish. The polishing can be done along with the wet sanding, but since it’ll hang to dry and collect dust, I prefer to polish last. Speaking of polishing, when I first started reading about how this is all done, I thought I’d need special material to rub on the compound and polish. So I bought a buffing pad and I’ve never used it. The reason I’m not using it is that I first wanted to practice wet sanding and polishing on a scrap piece of wood with lacquer, and I didn’t want to waste the buffing pad. For that, I used a white cotton t-shirt. The results looked great, so I stuck with it. It’s best to use an older t-shirt that has been washed a bunch of times. This way it has less lint. The compound and polish I use are Meguiar’s Ultimate Compound followed by Meguiar’s Ultimate Polish (in this order).

Here’s the end result. It’s hard to take a picture of a black finish, because it really just acts as a mirror. I think the Meguiar’s products do a good job and make it look real shiny.

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Shielding the cavities is pretty easy and cheap, especially if you buy something like this (2016 EDIT: this tape isn’t conductive on the sticky side. It’s not a big deal when shielding body cavities, but it can be a problem in other instances), which is way cheaper than copper tape and is just as effective. Taping along the edges with one long piece is a no go. The way to do it is cut small pieces and overlap them. It’s really tough to get around the tight curves like the one at the bottom of the cavity (where the jack would sit). Here’s the body all shielded:

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And a few close-ups:

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I took a picture of the back when I took the pictures of the shielding, and that picture looks better than those I already posted. So why not show it off.

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Here are things that I learned for next time:

  • Don’t wait 30 days to sand (but do wait 30 days to put the hardware on, etc.), just five days or maybe a week.
  • Plug well with Beeswax and don’t let so much water get on the body.
  • It’s better to go thick and not thin skin than sanding through. I was lucky this time around, but might not be so lucky next time.

As for the gouge — too soon for me to talk about it. Too soon.

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Done spraying color, one clear coat done, and spraying at 10″ away is the best

On Thursday I finally finished spraying the last color coats and touch ups for a few spots that had pits. These weren’t gouges that went all the way to do the wood, just spots I bumped into with my fingers, or that I tried to smooth out a run (hey, it actually works sometimes!)

Yesterday I checked on the guitar and sprayed a pass or two in a few spots that seemed to need it. One was a tiny pit that under light seemed to be white-ish. I was worried that it’s actually the primer, so I sprayed it. Another was a little speck. It wasn’t dust or a run, just a needle-head spot that had more lacquer than the rest. I thought that spraying over it can smooth it out.

Today I checked the surface for any more of those specks. There were a few, so I decided to scuff them with wet 800# sandpaper. I actually scuffed sanded the whole body with 800# as was recommended by someone online. The scuffing leaves scratches, but I believe (and hope!) that they get settled with the clear. In retrospect, sanding down those specks is dumb. There’s always some orange peel when spraying lacquer, and the pits in the peel aren’t any deeper than those specks stick out. So if the orange peel gets leveled with the next coats of clear, the specks should too. Here’s what the guitar looked like before going down to spray the first clear coat:

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And the back:

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I also learned how to improve my spraying technique, and that changed my world. When I first started spraying, I’d be 15″ away from the guitar, and I would go sort of slow. The result was a lot more orange peel, and a lost of material lost in the process. Someone at OSG saw a picture of the orange peel and recommended spraying closer — at 10″ or 8″ away. I did that but I was also spraying slower, so I got a ton of runs. Now I settled on 9″ away, and my passes are fast. It’s hard to describe how fast, but I’d say fast but not so fast that your hand starts jittering. I think a good analog is wiping a wet counter. You don’t go too fast so it splatters water all over the place, but still fast enough to drag the water with you. Anyway, doing it this way saves a lot of lacquer, and the coats come out real smooth and thin. That brings me to my last point.

The road to completing the color coats was kind of rocky — I had to do a lot of touch ups and changed my spraying technique, but the last color coat went down smooth and gave me a chance to figure out how much lacquer is used for one coat and how much it costs. Here’s the breakdown:

A coat of black (= 3 passes) at 10″ away + a few touch ups require a little less than 6 oz. of black lacquer. The lacquer is thinned 50/50. The guitar has 3 color coats, so that’s about 18 oz. of lacquer if there are no touch ups required. The cost of a quart of black lacquer is ~$20, so three coats comes out to $11.25. Also, I drop 20ml of black tint into the quart. I might be able to get away with less if I pour the clear into the the little glass jar, and then add the tint. Lastly, today I sprayed two coats of clear with a little over 3oz of lacquer each. So things might actually look better, although $20 for a quart of lacquer isn’t so bad (and less if it’s clear).

Now to deal with not getting dust on the guitar while spraying clear. That’s proving to be really, really hard. More when I have a solution for that.

Up and then down — it really hurts when your freshly painted guitar falls down.

Things were going really well. Yesterday I sanded the primer with #320, wiped it with Naphtha and got ready to paint it. I did one coat and it looked great. I think it was a little too thick, since I can’t see the primer underneath, but whatever, it works.

Today I went down in the basement to check on it (and get these two wooden blocks I found there to make this sort of a “stand” to put the guitar on when painting the edges), and my heart sank when I saw the guitar on the ground. The boom arm came loose somehow, and fell along with the guitar. Now it has a bunch of nicks all over its edges.

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I’m not sure what my next step is. Maybe it’s possible to spray those spots and fix them, but I might need to strip it all down and redo? Man, that would be a HUGE bummer, but I’ll do it if I must, especially since the areas where I sanded through the sealer show:

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Now I’m waiting to see what the good folks over at Reranch say, and I’m also trying to figure out how to spray the edges. The blocks idea wouldn’t work since the Jazzmaster is too bottom heavy and can’t stay stable on them. Might do the nail thing Fender used to do.