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:

IMAG0838

And the back:

IMAG0841

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.

Advertisements

More sanding, shooting primer, and thoughts about primer

I spent a few more hours yesterday sanding down the body. In the process I realized that removing all the primer until all I’m left with is the sanding sealer is kind of impossible and takes hours, not to mention that I sanded the bottom of the neck pocket a little to much, so now it’s radiused differently. Not a big deal, since it’s the bottom (i.e. back of the guitar). So I decided to get a uniform surface, and call it a day.

I didn’t reshoot sanding sealer in the spots I sanded through — I didn’t feel like mixing more of it, and it would have set me back a day. Most importantly, the primer is also a sealer, so as long as I get a uniform surface with the primer, who cares? Here’s what it looked like after sanding and without reshooting sanding sealer.

Image

Sorry about the lighting and quality. I do the work in a dimly lit basement.

Here’s what it looked like with the first coat of primer, sprayed from about 15″ away. Nice and thin.Image

Perhaps it’s not visible from the picture, but you can still see the grain through the primer, so another coat is in order. I also messed up a little bit when spraying the neck pocket edge (the horns). I did it a little too thick, and it started cracking, so I quickly sanded it down a little bit with #320 paper. Here’s a picture of it post sanding, and you can see the crack.

Image

As for using primer — I’m not really sure it’s that important if you spray sanding sealer. The sanding sealer gives a pretty hard, level surface to work with, and while the primer makes for an even more level surface, what’s achieved with the sealer is probably enough. No to mention that you probably need 2-2.5 cans of primer to do a whole body. I only used primer because it’s my first time spray painting and I’m doing a black finish, which supposedly show every little imperfection. I also wanted the finish to wear down to the primer over time (I’m not relicing it though), so I though “why the hell not?”. Next time I paint a body I’ll either just use sanding sealer, or make the primer myself with Mixol white colorant mixed with sanding sealer.

I’m off to see if the primer coat cracked over night!

Problems shooting primer

This is possibly the biggest pain in the ass so far. Shooting sanding sealer wasn’t fun and I went through two preval sprayers in the process, but I got it done with very few problems. The primer (Duralaq Nitrocellulose primer) proved more difficult.

I sprayed it at about 15″ away from the guitar and it came out too dry — wiping my hand on the body wood “dust off” some of the primer. It didn’t make sense and seemed like a waste of product, so I decided to spray it more wet. I got really close and got two a thick, level coating of primer. Here’s what it looked like.

ImageImage

Looks pretty good, right? Like Olympic White! Well, after 20-60 minutes it shrunk and cracked. Literally, cracks all over the body! I asked around over at reranch.com/reranch, and it turns out that shooting primer too close to the body will make it crack. I got within 5″ from it. Also, the primer coat shouldn’t be so thick. It should be thin and the thickness of the finish should be built with the color and clear coats.

Between yesterday and today I spent 4 hours sanding down the primer and I’m still not done. I also sanded through the primer in some spots, so I’ll need to touch up those areas. I’m hoping to be done with the primer by Tuesday, so I’ll be done shooting the color and clear by next weekend.