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Old 06-27-2020, 06:44 AM
0twentyone 0twentyone is online now
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Default Which current builders use the thinnest possible finishes?

I am of the camp that the thinner the finish on an acoustic guitar, the better it will sound. Now, this can't be a blanket statement, and it's not, as there are always exceptions. But, I believe it's generally true, and I'm curious which builders use ultra thin finishes on their guitars. And, which method of application and materials best suit this type of finish?
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Old 06-27-2020, 08:44 AM
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The finish I do for my Woodsman 00 model is as thin as I dare.
It’s an egg white seal with about 9 sessions of French polish with unbleached shellac flakes. I use no oil or filler in the process. It’s not for everyone, it protects the guitar from the elements but does little to protect it from the player.

Yes, I agree, finish tends to take sound away, the less the better if sound and response are your paramount concerns.

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Old 06-27-2020, 08:54 AM
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Quote:
Originally Posted by Mark Hatcher View Post
The finish I do for my Woodsman 00 model is as thin as I dare.
It’s an egg white seal with about 9 sessions of French polish with unbleached shellac flakes. I use no oil or filler in the process. It’s not for everyone, it protects the guitar from the elements but does little to protect it from the player.

Yes, I agree, finish tends to take sound away, the less the better if sound and response are your paramount concerns.

Mark
Mark, your work looks astounding. Look like works of art.
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Old 06-27-2020, 09:18 AM
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I'd say any builder working at a high level is going to apply a very thin finish. You probably want someone who does their own finish work.
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Old 06-27-2020, 09:23 AM
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I've never read of anyone suggesting that a thicker finish will do anything good for tone. Thus, virtually every guitar maker I've heard of attempts to keep their finish thickness thin. I would imagine that you are in the "thin finish" camp because you've read the same things.
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Old 06-27-2020, 09:26 AM
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John Greven formulated and uses his own, proprietary finish. He describes it as “hard but elastic, relatively safe to use, relatively quick cure (compared to oil varnishes), super transparent, non-yellowing with UV light, solvent resistant, water-proof, and able to be buffed to a high gloss like a conventional lacquer.” I can attest that the final thin film is stunningly clear, hard and has a three dimensional quality even though it is only .004”-.006" thick. I can see the texture of the wood surface.
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Old 06-27-2020, 10:43 AM
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i was reading John Bogdanovich book on classical guitar making and the first sentence in the chapter on finishing says “ Believe it or not, an unfinished instrument will not sound as good as one with a proper finish on it.” He went on to defend this statement but relating his experience of stringing up a guitar with no finish and being disappointed in the sound, which improved greatly after he had applied finish. He uses both french polish and nitro lacquer.

I think the thinner the better philosophy might be missing some other factors at play when it comes to sound production.

To be sure the term “properly finished” is an important caveat.

I have been farming out my finish work for the past 10 years or so to a guy who does this kind of work more or less full time. His finishes are perfect and uniformly measure out at 4 mills, at least on the top under the bridge where i have the chance of measuring the thickness. I think 4 might be close to the magic number at least for the type of finish he uses.
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Old 06-27-2020, 10:46 AM
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Yes, I imagine all high-end builders use as thin of a finish as they can, but I'm inquiring who might use an even thinner finish beyond that standard. Mark, your method is certainly interesting to me, and your instruments are stunning, btw. See, I have been a vintage guy most of my life, so the finest sounding examples I've encountered are the thirties Martins usually (some Gibson and Larsen Bros. examples as well) where the original finish is essentially gone or so ridiculously thin at this point in the guitar's life that it would probably be impossible to replicate. My '35 000-18 is like that. Ideally, I'd like to add a 000-28 from the same year or so, but finding one with original finish in decent shape is a very expensive endeavor. Looking for alternatives. No mention yet of French Polishing. I know it's very labor intensive and expensive, but will that finish be even thinner ? Classical builders swear by it and have for years. Same with the violin makers.
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Old 06-27-2020, 10:58 AM
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At this level, the luthier and how they build the guitar are so much more important to the final sound and responsiveness of the guitar than the finish applied to that guitar.
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Old 06-27-2020, 11:19 AM
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Well, John, I categorically disagree with that statement. Yes, all the components of the build are important and unique to the individual builder. But, in my opinion, finish is a huge factor and must be at the top of the considerations in the final result regardless of who is building the instrument.
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Old 06-27-2020, 02:02 PM
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Quote:
Originally Posted by 0twentyone View Post
I am of the camp that the thinner the finish on an acoustic guitar, the better it will sound. Now, this can't be a blanket statement, and it's not, as there are always exceptions. But, I believe it's generally true, and I'm curious which builders use ultra thin finishes on their guitars. And, which method of application and materials best suit this type of finish?
A couple thoughts to consider...

Choice of finish by builders is typically driven by a number of criteria: 1) application consistency; 2) protection from impact, 3) stability to temperature & humidity, 4) repairability and 5) handling safety. There are pluses and minuses to all finishes. Beyond the chemical and mechanical characteristics of any finish they are all highly process dependent and their thickness is a result of the artisan applying it.

In general, the thinnest finish is a well applied French Polish Shellac by someone skilled in the art. This can be .001”-.0015” thick. This is the finish of choice in the Classical guitar lutherie community.

There are steel string flattop luthiers who use a variety of Marine Varnishes and Oil Varnishes. These can be applied by brush or by spray application. A well applied varnish will typically be in the .003” - .005” range.

Nitrocellulose Lacquers are the most common finish, likely influenced by mainstay factories. A well applied nitrocellulose lacquer will typically be in the .003” - .005” range.

I own guitars with all of these finishes. All are outstanding sounding guitars. What is more important than the chemistry of the finish was the skill of the artisan who applied it and sanded it throughout the finishing process.

I actually agree with John Kinnaird’s comment that thinner is not always “better”.

Yes, I do think some very heavy (.008”-.012”) finishes on some high-end guitars do damp their acoustic performance. I have also seen the opposite where a luthier is used to tuning their plates and bracing expecting a .003”-.005” thick finish with certain damping characteristics. When they applied a new thinner finish with different damping properties, the guitar did not sound the way that they wanted. So thinner can only be better when the builder knows how to alter what they do ahead of finishing.
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Old 06-27-2020, 02:33 PM
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It is so much more complicated than "as thin as possible". Major factors include:

Moisture barrier
Impact resistance
Abrasion resistance
Surface Hardness Tonal effect
Weight
Rigidity
Longevity
Clarity
Flexibility (damping)
Bond to substrate
Time to cure
ease of application
Availability of product
Man hours
Actual cost

Most listeners actually do not prefer the sound of a guitar w/o any finish as some damping causes the sound to be more "beautiful", whatever that means. Response and volume not withstanding.

I have used many different finishes over my career, but I started out with hand brushed Oil Varnish, and after 20 years of experimentation, I have back to it for the last 200 guitars, though having learned to spray the stuff I am unlikely to brush again unless electricity becomes scarce. I could never get as consistent a film thickness with a brush as I do with spray. Measured in the center of the top when scraping back to glue on the bridge, I get a pretty consistent .0035" film thickness, though I once saw .0055.

Oil Varnish such as I use, is close to impermeable to almost all solvents, extremely abrasion resistant, weighs less than Lacquer by volume when dry, adds very little structure, has fantastic clarity, produces beautiful damping characteristics, and while quite labor intensive, is a pleasure to work with. IMO, of course.
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Old 06-27-2020, 02:53 PM
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Quote:
Originally Posted by Bruce Sexauer View Post
It is so much more complicated than "as thin as possible". Major factors include:

Moisture barrier
Impact resistance
Abrasion resistance
Surface Hardness Tonal effect
Weight
Rigidity
Longevity
Clarity
Flexibility (damping)
Bond to substrate
Time to cure
ease of application
Availability of product
Man hours
Actual cost

Most listeners actually do not prefer the sound of a guitar w/o any finish as some damping causes the sound to be more "beautiful", whatever that means. Response and volume not withstanding.

I have used many different finishes over my career, but I started out with hand brushed Oil Varnish, and after 20 years of experimentation, I have back to it for the last 200 guitars, though having learned to spray the stuff I am unlikely to brush again unless electricity becomes scarce. I could never get as consistent a film thickness with a brush as I do with spray. Measured in the center of the top when scraping back to glue on the bridge, I get a pretty consistent .0035" film thickness, though I once saw .0055.

Oil Varnish such as I use, is close to impermeable to almost all solvents, extremely abrasion resistant, weighs less than Lacquer by volume when dry, adds very little structure, has fantastic clarity, produces beautiful damping characteristics, and while quite labor intensive, is a pleasure to work with. IMO, of course.
I figure Bruce Sexauer and John Kinnaird are BOTH RIGHT. In the immortal words of Duke Ellington, (I think): "If it sounds good, it is good."

And I believe there is a lot to say for the ability of a good strong finish to protect the guitar from the player, as well as the elements! Now it doesn't have to be thick to do that, but it does need to be hard.

Whatever Tony Ferguson is doing for the Kinnard bros and others, is certainly working for me and John K

Play on and LISTEN

Paul
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Old 06-27-2020, 04:47 PM
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Hard can be a problem - if it doesn’t have enough elasticity, then it may easily crack with expansion or contraction or impact. Hard, by itself, is not the answer -
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Old 06-27-2020, 05:00 PM
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If you review some of our past builds posted on this forum, we post pictures of measurements of the film that I remove from the bridge and fingerboard extensions. Most are .001”-.0015” thick with a few outliers up to but never exceeding .003”. The Frisket Film I use to mask those areas is a consistent .001” thick so when I measure the total film, I deduct the Frisket Film thickness from the shown measurement. It’s very difficult to achieve that thin of finish but it can be done as I have shown numerous times.

When a builder subcontracts their finish work to someone else that final control of the final film thickness is lost. I understand some builders simply can’t spray in their location due to local codes and ordinances and that is unfortunate for them.
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