Official Luthiers Forum!

Hi guys

I'm finding finishing my guitars to be the most difficult aspect of the build.
I have tried French Polish which I like but want a harder finish
I have tried Tru oil which I also like but again want a harder finish
I have tried brush on lacquer which I didn't really like mainly due to the problems of the brushing technique.
I will probably try 'Rockhard' soon BUT..............

I'm now looking at Behlens 'nitro' in aerosol form and I'm wondering if anyone has ever used this and could give me some info on 'how' to do it but also if it offers a good 'respectable' finish for a (hopefully) commercial guitar.

Any help and advice on this would be gratefully received.

Many thanks

Mat

First off I want to tell you i have zero experience finishing acoutics but have sprayed many cans on solid body electrics. It is not difficult but there may be a tendency to put it on too heavy so be careful. Several very light coats are much better, less chance of runs and sags.

I also noticed that spray can finishes tend to orange peel, this can be lightly sanded out but it is annoying. I have been using Defts product on the recommendation of someone else-liked it and liked the price ~$4/can ay Walmart (I still prefer using my spray gun and thinner nitro).

Again, this was on a solid body so the finish was pretty thick (10 light coats), I am only guessing that the finish on an acoustic should be much thinner (fewer coats).

Hopefully you will get some more helpful advice from those with more experience.

Good luck

Steve

If saving money on tools is your goal in using spray bombs, I would advise looking for a used compressor and a cheap spray gun. Even a cheap gun will give a much better coverage and result than spray bombs. I am spraying behlen instrument lacquer on my 5th build with such a set up and get good results with it. I never tried any other finishes or application techniques as I already had the compressor and gun before building guitars.

Fred

_________________
Fred Tellier
http://www.fetellierguitars.com
Facebook page http://www.facebook.com/pages/FE-Tellier-Guitars/163451547003866

Thanks for the response

I will definately try spraying at some point. However, I don't have a 'safe' spray booth with a fan etc and i just thought that the cans would be easier to use at this stage.

Mat

Mat,

As an experienced wood finisher and a novice lacquer finisher, I can tell you the spray cans leave a lot to be desired.

1. Full pressure and they usually output too much and it is VERY easy to get sags and runs.
2. Not full pressure and it's VERY difficult to get even spray coverage.
3. Can to can consistency in spray coverage is not there. The spray pattern and coverage is slightly different and thus hard to control spray quality.
4. Overspray is a problem with a can spray.
5. The amount of "stink" from the spray can exceeds the level with a good quality lacquer for a gun.

I had to refinish the front of my only lacquered instrument and I got a quart of high quality lacquer that looked much like the rest of the instrument and resprayed the front with an airbrush (yeah, it's what I have right at the moment, I use it for touch-up on antiques) and the difference was night and day. Even coverage, level of smell was 1/2 or less of the cans. Just a much more pleasant experience.

If you are spraying lacquer of any kind buy yourself a resperator. You'll be glad you did on the first spray job.

_________________
RJS

Matthew,

Another problem that I've noticed with the spray cans is that they tend to spatter or splatter large globs
as you continue to use the can. You must constantly invert the can and spray it to keep the nozzle clean.
Then you must repeatedly wipe the nozzle with a rag doused in a cleaning solvent. All of this expends the
propellant thereby lessening the chance of being able to use the whole can of product. Also, the most expensive
way possible to finish a guitar is with a spray can. I would attempt a cheap Wagner paint sprayer set with a fine
nozzle rather than the spray can, but that's simply the option I would take if I didn't have the equipment I have now.
Other options above are also very good advice as well. As for spraying outside, I've constructed a temporary spray
booth outside in times past to finish large pieces of furniture. Some construction plastic and 2 x 2's from Home Depot
work great for an inexpensive booth. With the top left open you get fair ventilation then use a painter's mask (not paper)
for yourself. I hope the best for you in whatever method you choose.

_________________
Bill Hodge


One does not simply, own enough guitars!

Whether you use cans or a spray system the over spray, and bad for your health solvents will be the same. Get the best solvent respirator mask you can find.

The best part of guitar building is its addictive nature, everyone I build I spend more on tools than wood and building material, though I hope I have just about all I need after 5 builds but being a tool freak I will surely want more.

Fred

_________________
Fred Tellier
http://www.fetellierguitars.com
Facebook page http://www.facebook.com/pages/FE-Tellier-Guitars/163451547003866

There is a Top Notch areosol tutorial over on the "Project Guitar" Forum.

Several tips I can give, after having bad results flying blind... then good results following the tutorial's directions...

1. Buy 2 - 3 x more cans than you think you will need. Do not use a can for finishing past 1/2 full. They tend to spit and spatter when they start getting low. These half full cans are great for spraying sanding sealer coats, spraying Trailer hitch balls, and fence posts. Don't even try to use them for shooting your finish coats.... Trust me on this.

2. Get a bowl of luke warm water. It needs to be full enough to cover at least 1/2 way up the can. Stand up the can in the warm water for 5-10 minutes before starting, then between coats. The cans will cool off while spraying, and this causes trouble with getting even coats. The water helps warm them up and keeps things flowing right.

3. Buy 2 - 3 x more cans than you think you will need.... Rattle cans tend to spray much thinner mixes than Spray guns.... so your coating builds much slower than you think it does.

4. Because they shoot lighter coats if you are spraying correctly... you need to shoot more coats per layer/level between sandings or you will sand through.

5. Be careful about the spraying distance. Too close = globs and runs. Too far away = Orange peel and a "Dusty" look.

And last....
Don't spray under an Oak tree.... Don't spray it on too thick.... Don't let your hairy dog run around upwind of the guitar while you are shooting.... Don't wait 1/2 day for it to dry, then set a wool coat on top of it..... Don't wipe drips after it starts to get gummy.... Don't try to wipe off the bugs and leaves that fall out of the oak tree... Don't try to "Level" the coat with a rag and thinner....

and if you do any of the Dont's..... a good sharp Card Scraper works great for "Un-Finishing" a guitar...

Good luck

John

I have finished my first two acoustics with Deft laquer from lowes. It worked out great - outside under an old swingset. Deft is cheaper than the behlens cans - I used about 4 cans each guitar - about $30. I sprayed down to about 1/4 can before worrying about spatter. There was concern on my part that the Deft wasnt as good as behlens but another luthier advised me that Deft was fine to use - and he was right.
I was able to get a really nice and thin finish from it on both guitars and it has held up well.

All that said, I have 3 guitars ready for finish, so I bought a quart of behlens laquer, stew macs finish guide book, and will soon graduate to the compressor and sprayer... also have the material for a spray booth and a scrap exhaust motor from work so it is coming together, now if it would just quit raining.

I am always surprised by the lacquer thing…

Aerosol or compressor/gun do not make a difference in toxicity, either spraying or curing. If anything there are probably more solvents and toxic chemicals in aerosols. Application with aerosols and/or the Preval sprayer is uncontrolable.

Nitro needs to be formulated for musical instruments and have a certain elasticity/hardness ratio. I doubt Deft lacquer will last very long without flaking or cracking on an acoustic guitar.

Using nitro lacquer (or any of the "dangerous" finishes) requires a properly ventilated spray booth where the guitars can also outgas.
I view the outgasing of nitro as the most obnoxious part.

It's cool to wear a respirator while spraying and avoid coating one's lungs, it is also good to not smell lacquer thinner (or MEK) for too long.

In my book spraying toxic stuff outside is totally uncool.

I am sure someone is selling a 2HP compressor on any Craigslist at any time, anywhere in the US for less than $50. HF has a HVLP touch-up gun for about $20, and an air filter for about the same price.

There are other finishes less hazardous, oil varnishes such as Pratt&Lambert #38 or Behlen's Rockhard look awesome. They can be brushed or sprayed and the solvents used are harmless in comparison to lacquer. And there's always shellac…

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

First off spray cans will work. Deft is not what you want to use as there are additives in it. Over time you will have a cracked finish but I agree you can get an acceptable finish if you are lucky. The lacquer for guitars in cans will cost more but there is a reason and it is worth it. The solids content is higher.
Now to tell you the truth , the end result will only be as good as your prep. Also this process can not be rushed , so take your time. Allow a good 3 weeks for curing time. My schedule is to seal fill and seal again allowing 24 hrs between the coats . I use the sealer from the same company so I don't have compatibility issues . Then I will place a business card at the sound hole . Having measured its thickness first so I have an estimate of the build. I will then shoot a coat every hour for 8 hours or until I have .016 to .020. At this point I set it away for 3 weeks to cure.
Once cured I start the leveling process. I start with 320 to take out about 1/2 of the "orange peel". Then 420 - 600 wet 800 wet 1000 wet and then inspect . I look for sand through and level quality. This should have you to about .006 when you are done. I then hit 3 coats for finish. Here I want to get about .006 to .008 build. After 3 week I will start the actual finish buffing. I start wet sanding using 600 and I will work up to 1500. From there I start buffing using buffing compound polishing compound , then mezz and swirl remover. I will use maquires or 3m products. I like finnese it and gloss enhancer from 3m.
This process can take up to 40 man hours. A good finish takes time and patience.
I used either Behlen or MacFaddens. Behlen has an areosal can that isn't too bad. It will do the trick. The secret isn't what you put on but what you let on.
Still in the end , the results are what will make the guitar appear professional. Take your time and learn a a good technique. Once mastered you should have repeatable results. Prep and filling are the key to a successful outcome.
john hall
blues creek guitars

_________________
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

Thank you all for your replies, I'm finding this most helpful.

Laurent - I tend to agree with you on spraying outside, it's a good point.

Think I'll wait till I can rig up a decent spray booth. I think the spray gun would seem to be the best option for me. Untill then I guess it's on to the 'Rockhard'

Cheers

Mat

Hey Matt,

All good stuff on your question. I finished my first 2 guitars with cans and had some trouble with the splats and sputters. Do follow the DON"T list I can confirm some of those and add a couple. Don't touch a drip or sag let it dry and sand it out. Don't overuse your sand paper.

there is a good website that I had some luck with when it came to spraying with cans. The guitar reranch. Nice site for stuff with cans. If you ever want to try a burst without bunch of set up costs, good way to start. But eventually if you got the disease of guitar building you will do better with a spray set up.

You can do it though.

Karl

Here's my two cents - (take it for what it's worth - I'm on guitar number 5)
I've made the investment in a compressor and an HVLP gun - which I have not yet mastered, but even so, I'm happy with the final results.
As for toxicity - I've been using the KTM9 waterborne finish from LMII, because I don't have a professional true spray booth - I still use a respirator because I don't want to breathe the stuff - but exposure to nitro scares me without really good ventilation.
I think it's a pretty good investment, rather than the spray cans - and I think (others feel free to correct me) the waterborne finishes are "relatively" non- toxic.