Official Luthiers Forum!

I have French polished my last five guitars....I love the finish but hate its ease of easily being scratched...The most noticeable is on the soundboards....If there was someone in the area who nito sprayed guitars I would have them do it in an heartbeat...However there's nobody around here who does so I am looking at doing it myself...What setup do I need? Are there any instructional books or videos that I can buy.....Any info will be helpful....Larry

If you plan to set up for regular use you need a spray system. I recommend a Fuji MiniMight 3 or 4 (HVLP) for the price, quality and for the fact of not needing a compressor, filters, traps and dedicated spray gun.(a MiniMight will cost roughly $500-$600 gun and air tip included). A room or booth with EXPLOSON PROOF exhaust system,

If this is for an occasional guitar you can use Stewmacs aerosol can nitro in a well ventilated area with absolutely NO ignition source

In either case a good respirator is also required, as well as appropriate consumables (fillers, media, solvent, sandpater and such)

Now on the easy scratching French polish issue. If you spirit-off firmly between each body session, Glaze properly and allow the finish to cure a week or so before polishing out French polish should not scratch all that easy. Now if you are flat picking with out a pick guard you will get pick scratches from the repetitiveness. Besides if surface scratches from normal wear (not counting pick marks) is the issue than 15 min you have it back to smooth and shiny with little bother.

Can't comment much on the FP issue. I do it some and after cure, not a problem so far. I only have done a few dulcimers doing it and a couple of tops on guitars. 3 days to cure or harden isn't bad compared to nitro which I let set 30 days. I would go by what Michael recommends and make sure the process is right.

As far as nitro. Make sure have a room with exhaust fan and cross ventilation!!!! Boss has pro setup at his home. One thing if ever a flash fire in there, with his exhaust and other features it would be out in I think he said 30 seconds. I know also from insurance investigations, if not make the proper room and precautions and house or shop burns it is on you, PERIOD, NO DISCUSSION. He wouldn't fall into that, and made sure finish area was right from the start.

I use a Wagner HLVP 3 stage and wouldn't go with anything else. I bought an extra just on case the one have used 6 years goes bad. I am sure Wagner still makes them, but my model is probably obsolete. Get a decent gun, but doesn't have to be one of the highend units. I can use the boss's booth, and he recommnended some guns and hose things to set up on my own with his unit. I got it at O'Riley's. I am sure this will start a whole new argument. But like he said, most time it is in the doing the right process and setup than the equipment. Can have $800 gun and do a $10.00 job with it or a $50 gun and a highend finish. He has a less expensive gun, and does the best finishes I have seen. Over 30 years of experience helps.

Mask, get the best you can afford with good filter systems. I think have pair of coveralls or other clothing to protect the skin. Read Kims thing and that was just epoxy filler, think what finish can do. I don't have a problem with it, but don't want to either.

No matter what you use though, plan and make the spray booth right with right equipment. Don't have to go as elaborate as the boss or others who spray a bunch every year, but do need to make it so won't blow up or cause fire and at same time cause your insurance to go bad. They look at that as much as electrical if did it yourself or not with a contractor. This is one of those spend a dollar to save a bunch. You can do that and not go bankrupt doing it. As important as any tool or area of building in the shop.

If scratches are a concern then there's probably some Joe that'll put a truly durable finish on there for you at a good price. Setting up to spray is, IMO, more time and expense than it's worth unless you happen to live in the true middle of nowhere (which would make you neighbours with Mario!)

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

Bob Check your map of Labrador....LOL...Labrador City is in the middle of nowhere....and yes I guess Mario would be my closest full time builder....By the way Bob , do you do your own spraying or get a local guy to do it for you?

Michael Collins, the Canadian one, does UV polyester finishing. His new shop and spray booth are either operational right now or will be within days. He'll be doing all my finish work from now on for a number of reasons.

He's in Keswick, Ontario (not -reaaal- far from Labrador) and you can e-mail him at mjcollins3871 AT yahoo DOT com

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

...or me!

Farming out the finishing job is not an option around here, so I don't have much choice but to do my own finishing, and nitro is about as easy as it gets.

I spray it in a shed next to my garage, and I just leave the doors wide open and spray to the outside. My only costs are a nice touch-up gun and a compressor, the finishing material itself is also quite inexpensive. I spray all year, in all kinds of weather, the only times I try to avoid are really moist or super cold days.

Nitro is wonderfully forgiving, and hard to mess up if you follow a few simple rules. Keep it thin, sand smooth, allow for ample cure time and polish diligently; do this and it will look and 'sound' like a million Norwegian kroner. Of course there are other problems with it, such as toxicity, questionable long term stability and so on, so in no way do I think it is the 'perfect' finish. So far, though, I haven't found any alternatives that are good enough or easy enough for me to do to switch.

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Rian Gitar og Mandolin

Always wanted to spray nitro as well. I just didn't have the ability to set up all the needed equipment to work with it. So I went with water-based and had very good success spraying Target Coatings' USL on my last project. It's now been over six months, and the finish seems to be holding up very well. If you can do nitro, do it. It's a great finish. If it doesn't work out, you might want to consider Target Coatings.

Ken

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http://www.casperguitar.com

Spraying lacquer is not rocket science. It's dead easy with just a little practice, and common sense. I've taught so many apprentices that I've lost count, and am continually asked for advice on how to get the finish I have on my guitars. Believe me, I'm not any more gifted than the average bloke. It really is easy for anyone to get the same results.

I spray outdoors under a tin roof. I've got access to pro automotive spray booths at work, but they are just so busy that it's hard to get time in them, so I don't bother. You don't need any fancy exhaust fans when you spray outside. You don't fill your shop and or home with noxious fumes. The only downside is the occasional fly or mozzie that might land in the wet finish. So far not a problem for me, but your milage may vary. I know some spray in a screened enclosure like their back porch, just to keep the flies out.

When I spray I use a 50/50 cut to spray. You are not affecting the finish by cutting it more than the directions say. You just need to remember that you are not putting as much on with each coat, so will need more coats to achieve the same film build.

You have much more control of the thickness of the film build. It's much easier to apply a thin wet coat that will flash off very quickly, minimizing the chance of the aforementioned fly from sticking in the wet finish. If a chunk of crap lands in the finish, it's not buried in a heavy thick coat, just on the surface of a thin one. You just need to wait 10 minutes or so and very gently give it a rub with some fine sandpaper (say P400) to knock the lump out. If the finish looks too tender to do this, then wait some more.

I spray 5 coats like this. The next day I knock it back with P400 and let dry in a well ventilated place. Spray another 5 coats in a few days, and do the same the next day with the P400. By abrading the surface, the paint film will dry much quicker. You've created more surface area and broken through the hard outer skin of the finish. Then I let my nose tell me when to continue to level and buff. If I can still smell solvents when I put my nose to the surface, then it's not fully dry and ready to buff. Usually a week is all it needs, but could take considerably more if the weather is cold and humid, with poor air circulation.

You'll find that a lot of people will spray lacquer outdoors. They just don't advertise the fact. To date, only one of my instruments was sprayed at work in the booth. All others were done as I described.

As far as equipment goes, you don't need to go over the top. I use a very high quality automotive gravity feed spray gun, 'cause I've got a heap of them. Compressor is just a cheap Chinese one at home. You will also want to add a good oil and water trap. This is probably the most important, and also most overlooked item. You'll be cursing the day that you are spraying your finish coat and a big blob of water gets spit out with your clear 'cause you didn't install the separator you knew you should have bought.. Not an issue with any of the turbines that I've used though, so a plus for them.

Since a guitar is a small surface area, you don't need a large capacity gun. A pot just big enough to get one coat on will do. Many touch up guns can handle this, but don't buy a really cheap one. They are usually pretty dodgey at spraying a nice pattern. The Australian market is very different to the one in the US, so I have no idea about brand availability, or cost there. But without a doubt it will be a much larger choice, and far less expensive than here.

I like compressors and guns, because the compressor is good for so many other things. I tried to take stock of all the tools that are air powered that I own and lost count at 20. Turbines are also really good, but you miss out on the compressor, and are hooked into a one use tool. Only you can be the judge of one over the other for your circumstances.

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Allen R. McFarlen
Barron River Guitars & Ukuleles
Facebook
Cairns, Australia

IMHO the major pitfall of nitro is outgasing. Unless a proper spray booth where the parts can cure is used, you and people living with you will be breathing that stuff. It stinks, lingers for a while and is toxic even if the material is forgiving. Also you'll be using a fair amount of lacquer thinner to clean the gun and materials. Why not try an oil varnish? It can be brushed or sprayed and is much less dangerous and toxic. I agree that a compressor is a useful tool.

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/