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  #1  
Old 04-07-2013, 10:29 PM
wisedennis wisedennis is offline
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Smile ☆☆★★☆☆Difference between Poly-finish and Nitrocellulose Finish☆☆★★☆☆

What are the difference between Poly-finish and Nitrocellulose Finish?

Is it a big difference or a subtle one?



Thanks!

Dennis

If the structure/bracing and wood are all the same,

what difference do this 2 finish bring to the guitar?

Last edited by RP; 04-07-2013 at 11:14 PM.
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  #2  
Old 04-07-2013, 10:43 PM
duluthdan duluthdan is offline
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This from Luthiers Merchantile International:
"Nitrocellulose lacquer, however, has been the primary wood finishing material, and American guitar factory preference, for over eighty years. More recently polyurethane, polyester, and other catalyzed coatings have been used in guitar manufacturing and the quality of water-based finishes has increased steadily so that now the best of them equal or exceed the quality of nitrocellulose finishes . The more exotic synthetic or catalyzed finishes are best suited to factory situations, not to the average small-scale guitar maker."

That being said, I do have a $99 guitar that had a rather thick layer of poly on it, and I scrubbed it down with automotive rubbing compound. This is my experimental guitar - it taught me how to install a nut, and do a setup, soon it will sport different tuners, and if I really get bored, scalloped braces.
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Old 04-07-2013, 10:48 PM
GuitarLight GuitarLight is offline
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The both finishes are good if they are done well. Poly tends to be much more durable, easier to clean, stains less, is more water proof and sweat proof, and looks like Nitro when done right. Nitro is beautiful but less durable in the sense it stains much easier with sweat...or beer. Satin poly is probably the most durable but does not have a shine finish like regular poly or nitro. Most necks today, including Martin and Taylor use a fine poly durable finish that aids in reducing neck stickiness, where as Nitro like on most Gibsons gets sticky when it absorbs sweat and can fog up the finish. Poly is virtually sweat proof and remains much less sticky on the neck when used hard. I prefer Poly over the Nitro or lacquer finishes for this reason.
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Old 04-07-2013, 11:03 PM
epaul epaul is offline
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I agree, in general, with much of what you said, regarding the two finishes, but if Martin has switched to using a poly finish on the necks of any of its guitars, that is news to me, and, I suspect, most of the guitar world, including the Martin Company.

.

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Old 04-07-2013, 11:10 PM
epaul epaul is offline
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Oh, and there is no inherant difference in durability between a satin finish or a gloss finish, whether the finish is nitro or poly (poly urethane or poly acrylic). Individual finishes and finish types can, and do, vary in durability, but whether they are gloss or satin is not an indicator of their respective durability. The same finish type can be formulated to be gloss, satin, or flat without altering any of its protective qualities.


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Old 04-07-2013, 11:19 PM
epaul epaul is offline
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But, you did get much of it right.

Nitro finishes are susceptible to a number of solvents, some of which, unfortunately, are produced by Homo sapiens (us). Poly finishes are impervious most solvents (you would have to be poking around a well-stocked chemistry lab in order to cook up something that would dissolve a poly finish, beer sweat, plastics and vinyls, and mosquito repellent and nacho dip certainly won't faze it.

Oh, and a well applied poly-type finish won't finish check if you happen to leave your guitar out in below zero weather and bring it in the house and pop the case open. Nor will it check and wrinkle with age.

(Taylor has tested their finish to -10F, which is as cold as their freezer goes, and the finish comes out of the freezer fine and dandy.)
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Old 04-07-2013, 11:23 PM
epaul epaul is offline
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On the other hand, outside of one neck that got so sticky I couldn't stand to touch it, let alone play it, I really haven't had any trouble with any of my Martins. I do wipe them down after playing and take some basic care with them.

But, I do prefer a poly finish, all things being equal (which they seldom are) as it is just plain better at doing its job than nitro is.

.
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Old 04-07-2013, 11:26 PM
GuitarLight GuitarLight is offline
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A poly satin finish is less durable only in the sense it often wears smooth and can buff to a shiny area in the areas where it is repeatedly touched by the skin. Other than that it is as durable as any regular poly. I owned several high end Martins in the past, and called the Martin factory around 2001 when I bought an HD-28 ( I live near them) to inquire about the neck finishes because I liked the Taylor finish necks for their smoothness and non-stick qualities. Martin at that time, (and things could have changed since then) ...told me that ALL high end Martins continue to use a premium lacquer finish on the bodies of their high end guitars, but that they now use a poly finish similar to Taylors for all the necks because it is superior to Lacquer for both play-ability and durability. My present 2002 Martin J-40 also has a regular lacquer body finish, but the neck is gloss poly on it, almost undetectable from the lacquer body, and this was verified by Martin to me by phone. The neck on the Hd or the J-40 has never stained, fogged or become sticky even during heavy sweated play. Martin told me this was the reason they had converted to the new neck finish at that time. I do not believe they have made it public knowledge in general. Neither my J-40 nor my HD-28 stated a poly finish on the neck in the specks, but I suspected that it was by the way it felt, and the fact that they never got sticky like my Gibsons did during play and high humidity conditions. My phone call to them at that time confirmed it..but they did not seem to be overly anxious to tell me this, perhaps they feared repercussions from people who did not approve of poly on expensive guitars in those years. Today the poly neck finish is very common and well accepted. A welcome change. Gibson would do well to follow Martin and Taylor in this respect IMHO.

Last edited by GuitarLight; 04-07-2013 at 11:54 PM.
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Old 04-08-2013, 12:05 AM
FrankS FrankS is offline
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Poly just means "many" as in repeating units. That is what a Poly-mer is. Using Poly to refer to any particular polymer is like saying things that fly. Does that mean birds? Planes? Kites?

Enough of semantics. Now to the chase. The backbone of the polymer will determine the ultimate properties that can be achieved. While it is true that polyesters will have one general set of attributes while polyurethane or polysaccharides will have others, there is a great spread in properties that naming the polymer does not really help to figure out what the performance is.

If forced to categorized finishes, I would most likely have to call them linear or branched. An example of linear is nitrocellulose lacquer. A property of some linear polymers is that they can be dissolved in solvents and applied that way. Branched polymers do not dissolve so they have to be cured in place. So one attribute that is clear is that nitrocellulose is linear so it can more easily be affected by other solvents that might come in contact with the coated surface. Branched polymers tend to be more resistant to solvents.

There is more but I suspect people have already stopped reading this post at this point because it is too technical so I will stop here.

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Old 04-08-2013, 12:48 AM
billgennaro billgennaro is offline
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does anyone know about repair work as regards to the different finishes? i've read that poly finishes cannot be touched up whereas lacquer is much easier to work with as far as repair work is concerned.
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Old 04-08-2013, 02:44 AM
HeimBrent HeimBrent is offline
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Personally, I like the way nitro ages. I prefer it when a guitar that has been played for ten years looks like it as well. But it's all a question of personal preference. If you want your guitar to look pristine, even after ten years of playing, poly is what you want.
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Old 04-08-2013, 08:10 AM
Dwight Dwight is offline
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Quote:
Originally Posted by billgennaro View Post
does anyone know about repair work as regards to the different finishes? i've read that poly finishes cannot be touched up whereas lacquer is much easier to work with as far as repair work is concerned.
Taylor can, many small shops can't.
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Old 04-08-2013, 08:22 AM
Von Beerhofen Von Beerhofen is offline
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I get the impression that nitrocellulose is softer and scratches more easily then poly-urethane. Can't say if it will harden over time.
On top of this, as mentioned before, nitro tends to react with sweat and leave a guey stain behind when touched with bare skin, which is not easy to remove unless vigorously rubbed.

Ludwig
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Old 04-08-2013, 08:34 AM
RiloKiley RiloKiley is offline
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Why does somebody so wise have to put so many stars in their thread title?
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Old 04-08-2013, 08:47 AM
Bugeyed Bugeyed is offline
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My guitar finish is acid catalyzed lacquer. What are it's properties when compared to other finishes? BTW it's a hand rubbed satin finish.

kev
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