Nitrocellulose vs. Other Finishes

Re: Completed the set! Updated with a slight tale of woe!

West R Lee said:

Ribeye steak Carl, salad and a wonderful bacon, cheese and potato conglomeration....topped off with red velvet cake with cream cheese icing.......very dietetic.

So you guys are saying this Dave Gonzalez with Guild is dead wrong? :? And Guild should be finishing their guitars in polyester because it is superior to nitro?

West

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Yum !!!!

I wouldn't say Gonzalez is wrong, it's just their choice to use nitro rather than to be contemporary. Gibson also uses nitro exclusively. The nonsense about the finish allowing the wood to breathe is just marketing nonsense, but it probably sells a guitar or two; maybe even three :mrgreen:. For whatever reason they feel that staying with nitro will meet their target customer better. Some buyers want a traditional nitro finish. Martin still uses it on "traditional " models. Only time and sales volumes will tell if Guild is "wrong" in their decision.

Personally, I don't think there is any question that UV-cured polyester is a superior finish in terms of protecting the guitar and lack of problems. It does not mean I would never buy a nitro-finished guitar if one really knocked my socks off. But given two similar guitars, I'd go with the UV-polyester. That's just me.

I have a newish (non-Guild) guitar with a nitro finish; it's just too damned delicate and I hate to have to worry about dinging or denting it, which often occurs, when it's out. My Kyser capo even left a white mark on the neck.

Poly finishes are so durable and tough, and I think, thickness of coats being roughly equal, few human ears can discern any tonal difference. The nitro finish is generally prettier—you can see the ridges of grain better, but it's like the old laquer finishes on furniture that got permanent white stains whenever a drop of liquid was not immediately wiped off—an unnecessary anachronism. I don't think there's a huge difference in the cost of application, both are sprayed basically the same way. I have to think that the older apps of nitro were perhaps more durable, older Martins and Gibsons and other forty-year-old guitars I've seen may have age cracks, or even a few bubbles, which don't much bother me, but seldom have the denting, chipping and stickiness issues that plague modern nitro guitar finishes. I'll take poly everytime.

Wontox

Joe,

I may be the odd man out

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Not at all, Joe. You're the odd man in.

But seriously, I wouldn't add anything on a guitar except to restore it. I read somewhere that you can rub something on crazed lacquer and it sort of makes an emulsion out of the top of the lacquer that fixes the lacquer checking. However, I don't recall anything about whether such treatment alters the sound.

I don't normally see myself as a stodgy traditionalist,

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That's how I see myself.

Re: Completed the set! Updated with a slight tale of woe!

AlohaJoe said:

... I may be the odd man out, but finish checking doesn't bother me. I'm not much of a woodworker and I'm certainly not a chemist, but on a wonderful old vintage instrument an aged look to the finish is an enhancement to me.

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Hi AJ; I think we're talking about two different things; the 'checking' on Grot's #99 - where this all got started - is stress fractures in the finish caused by thermal shock and not the natural 'checking' of nitro, varnish, or lacquer caused by aging, oxidation, and shrinkage. This is the type of checking that Carl says doesn't happen in the polyester-UV cured finishes on Taylor guitars. The issue isn't aesthetics ... it's the cracks. (copy of pic of Grot's #99 from this thread.)

I'm cornfused. Isn't the checking picture just aesthetic?

HF (The corniest flake)

I do not find "breathing" to be such an issue since the guitar is unfinished inside. And yes that seems to be marketing bologna. One question I have is about flexibility of the finishes. It seems we are always taught, or maybe it is just my impression, that nitro is flexible thus allowing the wood to resinate more easily. How is this in the case of a thin layer of polyester on a Taylor?

Yes the finish is there to protect the guitar from spilled coffee on the table, but the finish should not inhibit the wood from vibrating to its fullest potential.

There's an old hodrodder's saying :

" IF IT DON'T GO, CHROME IT!!"

My old 25 looks like it has been carved up with steak knives the nitro is so cracked.

I think it has no other choice but to have an effect on the sound, and it sounds spectacular.

Ridgemont said:

... It seems we are always taught, or maybe it is just my impression, that nitro is flexible thus allowing the wood to resonate more easily. How is this in the case of a thin layer of polyester on a Taylor?

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I wondered about that too ... it's probably possible to take a couple of tops ... or guitars - one finished with polyester and the other with nitro - to a materials testing laboratory. Assuming science can measure anything, they could doink the tops and see which one resonates / vibrates / moves up and down the fastest (but not too fast ) and which one comes to rest the soonest (but not too soon) :wink: .

Further, let's say we actually knew which one was more flexible or whatever attribute we're looking for; we'd then approach a panel of luthiers and manufacturers and, chances are, there'd be no standard ... no widely accepted idea ... everybody would have a different idea (their idea) about top characteristics that they believed most conducive to good tone (as if we all could agree on what that was).

I mean who knows how much real latitude there is between too tight and too loose and who's to say that other factors such as top materials, aging, thickness, moisture content, and thickness of finish don't have as much to do with the behavior of the top as the type of finish itself. We all understand that two identical guitars can sound different; I suggest that it's possible that subtle differences in how fast the top vibrates is one of the dozens of little factors in that perception.

Respectfully, I think Mr. Gonzalez' remark about nitro and resonance ... it's more puff. He isn't lecturing on the hows, whys, justifications, and trade-offs in making Guild guitars ... he's trying to generate interest by inflaming his viewers with ideas like an 'organic' living, breathing guitar .... that produces the ultimate in woody, resonant tone. These are ideas he's talking about ... not physics.

capnjuan said:

Respectfully, I think Mr. Gonzalez' remark about nitro and resonance ... it's more puff. He isn't lecturing on the hows, whys, justifications, and trade-offs in making Guild guitars ... he's trying to generate interest by inflaming his viewers with ideas like an 'organic' living, breathing guitar .... that produces the ultimate in woody, resonant tone. These are ideas he's talking about ... not physics.

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I am not looking for puff. I can find that anywhere. If nitro does allow the wood to resonate to its fullest potential, then that as a reason to why nitro is better. But like you said, there are many variables in guitar building. The real question is whether using nitro as the finish variable in the guitar building equation makes a substantial difference in the final product.

A nitro finish is made from cellulous, which is plant fiber, and a solvent. The solvent off-gases during curing, and can then combine with other pollutants in the atmosphere to cause smog. A polyurethane [edit: or polyester] finish, like almost all plastics, originates from petroleum. Like almost any manufacturing processes, there are competing environmental upsides/downsides.

It makes sense to me that a nitro finish could very well be more breathable, in the sense that it is relatively but incrementally more permeable to water and perhaps other vapors than a poly finish. This could have some advantages, as in allowing the wood to better stabilize, cure, dry out, what have you, particularly at the contact surface. As has been pointed out, the wood on the non-contact surface inside the guitar is openly exposed to air. A nitro finish could be more flexible. As has been discussed, it could be more resonant. There is more predictability in the effects of aging on a nitro finish, as it is the much older technology. There is also predictability in that if you subject it to extreme temperatures, you are going to cry. I know first-hand.

I do not care for the modern quasi-electric guitars, including their plastic finishes. Utilitarian, pedestrian, no soul. Why not just make the entire guitar out of plastic? But, then again, I’m not performing regularly or trying to make a living at it. Worse, I am (or have been!) crazy enough to gamble on beat up old guitars on craigslist and paid enough that I could have bought instead a super predicable, trendy, economical, nuts and bolts guitar with a warranty.

I am trying to say that a poly finish is not, and will never be, inherently or intrinsically better than a nitro finish on guitars. Dave

Then of course I've heard of tops that were 'sprayed' on both surfaces... :? Steffan

Ridgemont said:

capnjuan said:

Respectfully, I think Mr. Gonzalez' remark about nitro and resonance ... it's more puff. He isn't lecturing on the hows, whys, justifications, and trade-offs in making Guild guitars ... he's trying to generate interest by inflaming his viewers with ideas like an 'organic' living, breathing guitar .... that produces the ultimate in woody, resonant tone. These are ideas he's talking about ... not physics.

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I am not looking for puff. I can find that anywhere. If nitro does allow the wood to resonate to its fullest potential, then that as a reason to why nitro is better. But like you said, there are many variables in guitar building. The real question is whether using nitro as the finish variable in the guitar building equation makes a substantial difference in the final product.

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Hi Ridge: the point is that other than elaborate scientific tests, there's no way know for sure whether nitro allows, permits, or causes tops to resonate any better [assuming that can be defined] than some other finish does. It might be true ... I'm not even saying it's not true ... all I'm saying is that it isn't true just because Mr. Gonzalez says it is and Guild fans who prefer a nitro finish believe it is.

capnjuan said:

Ridgemont said:

capnjuan said:

Respectfully, I think Mr. Gonzalez' remark about nitro and resonance ... it's more puff. He isn't lecturing on the hows, whys, justifications, and trade-offs in making Guild guitars ... he's trying to generate interest by inflaming his viewers with ideas like an 'organic' living, breathing guitar .... that produces the ultimate in woody, resonant tone. These are ideas he's talking about ... not physics.

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I am not looking for puff. I can find that anywhere. If nitro does allow the wood to resonate to its fullest potential, then that as a reason to why nitro is better. But like you said, there are many variables in guitar building. The real question is whether using nitro as the finish variable in the guitar building equation makes a substantial difference in the final product.

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Hi Ridge: the point is that other than elaborate scientific tests, there's no way know for sure whether nitro allows, permits, or causes tops to resonate any better [assuming that can be defined] than some other finish does. It might be true ... I'm not even saying it's not true ... all I'm saying is that it isn't true just because Mr. Gonzalez says it is and Guild fans who prefer a nitro finish believe it is.

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My issue is that up till now, we have been going off of peoples opinions....very subjective and given the guitar enthusiast culture and human nature it is pretty easy to predict each persons opinion. A wise man once told me that opinions are like @--holes...everybody has one and everybody else's stinks. Sorry to be a tad uncouth, but it sort of fits the bill. I am with you Cappy. I would like type of scientific study that produces realistic objective data to determine which is better. But even then, does it matter, and can we really tell the difference in a blind test of 2 guitars with different finishes.

Ridgemont said:

... But even then, does it matter, and can we really tell the difference in a blind test of 2 guitars with different finishes.

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Probably not. Carl's point was that UV-cured poly withstands temperature shocks better than nitro does. About all that can be said with certainty is that Guilds have an attractive, reasonably long-lasting, and repairable finish ... that's vulnerable to thermal shock. Taylors, by contrast, have an attractive, reasonably long-lasting but difficult-to-repair finish ... that's practically immune to thermal shock. The rest of it? Who knows ... :? :wink:

Not being a pain but guitars don't breath, they're dead wood. Lacquer is the ONLY way to go on an acoustic, the thinner and more dried out the better.

Polyurethane finishes are so flexible that they suck tone from an acoustic like a sponge and the stuff never get's hard.

curt said:

... Lacquer is the ONLY way to go on an acoustic, the thinner and more dried out the better.

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Hi Curt: by lacquer ... do you mean nitro or conventional lacquer? If nitro, why is it the only way to go?

This isn't a trick question; I'm interested in knowing why a pro would be so strong on the product.

curt said:

Not being a pain but guitars don't breath, they're dead wood. Lacquer is the ONLY way to go on an acoustic, the thinner and more dried out the better.

Polyurethane finishes are so flexible that they suck tone from an acoustic like a sponge and the stuff never get's hard.

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From this statement, are you saying that dry and brittle lacquer is best? Could you please elaborate? My initial impression was that flexibility is essential, but maybe I am missing something. What about polyester finishes?

Regarding thickness of nitro finishes vs polyurethane, I have a '67 Vox Country Western (basically a copy of the Gibson CW) with an original incredibly thick coating of nitro, I mean you can see the finish edgewise if you tilt the guitar....the 44 year-old finish has a dozen or so longitudinal age cracks on the top, none elsewhere, which maybe hints that the cracks are caused by vibration of the top, rather than temperature issues. The guitar has a fairly muted tone for a jumbo, probably largely due the the thickness of the nitro, my point being that you can apply nitro just as thick as an overly thick coating of polyurethane. The Vox has kind of a cool low-key but boomy sound, which is desirable to me for its difference from other guitars. I don't know that I'd like the sound without the dense coat of nitro.

It's all a matter of the finisher's choice. As stated previously, I'm a poly fan—with coatings being equally thick—the poly's much more durable than nitro, and any tone difference is so minute as not to bother me. I hate having to baby a guitar, to not take it outside, or leave it uncased for a while, be able to sit only in a certain chair, not let others play it, not let direct sunlight on it, etc... I have little need for authenticity or historicity, or 'the old way' is better just because...
Wontox

For a more percussive sound, why not finish the guitar with nitroglycerine?

Darryl Hattenhauer said:

For a more percussive sound, why not finish the guitar with nitroglycerine?

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Good bang for your buck.