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I'll be spraying lacquer for the first time coming up here in the next few weeks. How do you typically clean the gun AFTER spraying a coat? With poly I needed to spray MEKP immediately following each coat, and I could only mix enough finish for the coat at hand since it solidified immediately after spraying. I'm wondering if I can put thinner in one cup, a day's worth (3 coats) of lacquer in another, and just interchange them, spraying the thinner after each coat of lacquer and only filling the lacquer cup once a day?

I've left lacquer (assuming you're talking nitrocellouse lacquer) in my gun for several days. No need to clean between coats. The solvent disolves the finish in the gun.

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I usually spray my 3 coats in one day then clean the gun with lacquer thinner so it will be clean for the next day. I've never tried leaveing it in the gun for more than a day, but that might work as well.

Lacquer is very forgiving in the gun, I leave the gun between coats as Mark says, but I close the needle. I have left it overnight without any problems. I give the gun a good cleaning after I am done, this requires taking it apart to clean not just blowing some thinners through it. Use some high grade gun lube to oil the needle so it won't stick to the packing. The 1st spray on the next use will get rid of the lube if it is in the fluid transfer areas.

Fred

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Fred Tellier
http://www.fetellierguitars.com
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Lacquer can be left in the gun for a while. My guns finish is not harmed by lacquer solvents. As for the spray schedule I shoot 8 coats on the first day , one hour apart. Let set 3 weeks then level sand. Lacquer is as much about technique and prep . You want to have about a .016 to .020 build. then level sand back and a few coats of finish spray to buffing and polishing.

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Thanks, guys! It sounds much more forgiving. Poly wasn't hard to spray or mix, but it was time consuming for the one run guitar maker and difficult to buff. I'm really looking forward to putting the mask on and learning about lacquer. Especially since it seems so easy to use.

Thanks for the tips on your schedule, John. I haven't heard of anyone doing 8 in a row before, but it sure seems convenient. I was planning on 3 coats, 3 coats, level and repeat again. I'll need to do more research. Yours is the most appealing!

I use CF Martins finish schedule . It works for me

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

I think I'm going to go with it. Thanks, John. Do you thin the lacquer?

If I leave my guy for most of the day I soak a small piece of rag with thinner and put it on the end of the gun then rubberband a piece of plastic over it. It might not be all that necessary with laquer but can be used with oil, or water based finishes to good end. Good luck on your first shot. With my rig I found I had to get a slower thinner. This made all the difference.

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I always shoot thinner for a few seconds after spraying a coat.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

I'm going to go ahead and do that. I have the 3M PPS system, so snapping in a cup with thinner only takes a moment.

James the 3m PPS looks interesting, have you had it long and why that system?

I'm with Howard - a 10 second burst of thinner through the gun after each coat. A full cleaning after the last coat of lacquer. I also learned to pour anything I put into the gun through a fine mesh strainer. That solved a couple of issues I had early in my (ongoing) learning process.

Good luck.

Chuck

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I've left clear nitro in a gun for months and go right back to spraying.
I don't recommend it however just for the principle of it.
Speaking of straining, what do you guys use for straining aniline dye after dissolving in thinner or alcohol?
I use cloth (couple layers) rather than a fine mesh strainer but it's messy because the cloth absorbs a lot of the solution.
Is there a super fine strainer somewhere out there?
Thanks
Nelson

I've used it once to date, and I bought it at Rick Turner's recommendation. It makes clean up and mixing so easy.

James,
Lacquer is a great finish. You can leave it in your gun overnight, but not beyond that. It will clog your gun if you do.not clean it right away. Lacquer melts into the previous coat, so the coats do not stack up like enamel or some other finishes. But the thicker you make it, the nicer it will look. Many luthiers will put 8 or 10 or even more coats on the guitar. Spray, and wait. Spray and wait. Then buff. Buffing is the most sensitive part of the process. You can burn through the finish in a second. Be very careful when buffing. Use lacquer thinner to clean your gun. If you ever get the opportunity, take a class on using lacquer. It will pay off. I use nothing but nitrocellulose lacquer on everything I build. Furniture included. It will outlast anything on the market. Martin uses it.

Todd, how do you measure build thickness?

On my last guitar I tried 6 coats on the top, nine on the back, and twelve on the sides. It turned out very well, and the top coat was nice and thin, about 4 mil. Best sounding one to date, but it was only #4, so I am no expert - though I have a lot of spraying experience on other things. I have a true HVLP system I bought for spraying an aircraft I was building, and I like to thin about 50:50. I pull the nozzle and needle and clean them if I leave lacquer in overnight. To measure the thickness I use a micrometer, some of the lacquer flakes off the tape when I pull it off the bridge or fretboard area.

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Damon Wack
https://www.facebook.com/LindamonGuitars

James, I spray on glass panels (4"x6") with a paint stick taped to one side to hold. I use a razor blade to peel off the film for measuring. There are also wet mil gauges available from good paint stores that are the size of a biz card with graduating sides for measuring the wet film. I am not really concerned with the wet film so the glass cards offer a way to give the dry film a closer look. Might be handy to have several cards and spray them with different reductions and gun settings to get the film build per coat that you are after.

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jw ( o)===:::

With the acetate covers I use inside f-holes, held in place with a balloon, finish flakes off easily after removal..... shows actual deposition, easily measured.

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Dave
Milton, ON