Acoustic finishes

[Ostracized]

Hey guys,

 

I'm just curious what the ideal finish for an acoustic guitar is. A couple of guitars that I am interested in are the Larrivee D-03R and one of the Guild GAD dreadnoughts.

 

The Larrivee has a 'no finish' finish which I really don't care for. The Guild apparently uses a high gloss polyester.

 

And then there is nitro-cellulose, which seems to add about $500 at least to the price of any guitar.

 

I guess my question is, how different is polyester from nitrocellulose in terms of tone, aging, durability, etc.?

[rjoxyz]

In very general terms, nitro is felt to be more conducive to realizing the full tonal potential of a guitar. It is usually applied thinner than poly and allows the guitar to vibrate more freely. It requires careful handling as it can be damaged by some chemicals and materials used for stand padding, straps, etc. Poly is likely to be more durable and less chemically reactive.

 

I have 2 Larrivees and they have a poly finish. Not sure what you mean by "no finish".

[Ostracized]

Well, the Larrivee 03 series has a matte finish....basically seems as if they just didn't finish it.

[Hudman]

 

Well, the Larrivee 03 series has a matte finish....basically seems as if they just didn't finish it.

 

 

They use a poly based satin finish. It's just not buffed to a gloss finish.

[AK47]

This is my understanding that guitars pre 1900 were shellac, varnish, and various other finishes. With the invention of spray finish nitro came to be the standard. Nitro is fragile and wears with time so experiments with polys have been done to get a more durable finish. It is also my understanding that poly doesn't have to be thicker than nitro but cheaper guitar companies tend to pour it on.

 

It is my opinion that the satin [no finish] guitars look better under the lights of a stage. They don't show glare, nasty smudges or fingerprints.

[Freeman Keller]

 

Well, the Larrivee 03 series has a matte finish....basically seems as if they just didn't finish it.

 

 

Many moderately priced guitars are satin finished - in some cases it will be exactly the same product used on gloss guitars, they just won't have the final polishing (which involves a lot of hand labor and thus runs the cost up).

 

Back to the original question - traditional finishes where variations on shellac used on classical guitars (often called French Polish) and nitrocellulose lacquer (still used today on Martins and most boutique steel strings). Some modern finishes include UV or other catalyzed finishes (like Taylor) and various polymer finishes (many imports, I think). Some builders are starting to use waterbased lacquers for environmental (and safety) reasons.

 

Nitro is (was) popular because it can be applied very thin and still buffed to a very high gloss - the poly finishes are popular because they are pretty easy to apply and look pretty good (they tend to be thicker). Nitro is easy to fix if you have finish problems, but it does take a lot of expensive hand labor to make it really look nice.

 

Many people (including myself) have polished satin finshed guitars to what I would call "semi gloss" using hand products and the back of the neck will gloss itself with play (let me know if you want a link to how to do it).

[guitarist21]

 

Well, the Larrivee 03 series has a matte finish....basically seems as if they just didn't finish it.

 

 

Like Hud said, but just to make it really clear, the 03 series is finished. It just isn't buffed to a high gloss. My Epiphone Masterbilt is the same way. Some people like it, some don't. I love it. I think it looks great in pictures. Its not shiny on stage but I can roll with that. Don't need to look great on stage with a band that the other guitar player has a banged up Squier Tele covered in stickers for skateboard companies.

 

Ellen

[DeepEnd]

 

. . . And then there is nitro-cellulose, which seems to add about $500 at least to the price of any guitar. . . .

 

Not necessarily. Waldens use a nitro finish and they're quite reasonably priced and well liked.

[leftync]

I used to feel the same way about satin finishes as Ostracized. Then I bought my son a used S&P Mahogany, essentially the same guitar as my Seagull M6 but with a different finish. I thought the Seagull had about as good a sound as a guitar with laminate back and sides could. But the S&P sounded even better. I then played a couple of Larrivee 03s, and I bought a D-03R. I think it's an even better finish for sound. I was prepared to spend more, so while it's nice that it doesn't cost as much, it wasn't a necessity. I like the Masterbilt, and might have considered one if it was made left-handed. But I doubt you'll find the combination of materials and workmanship of a Larrivee anywhere else. I match the rosewood dreds with any guitar I've heard at any price. I truly preferred its sound to Martins and Taylors costing $2K or more, and I don't think I'm alone.

[tim Mcknight]

 

Hey guys, I guess my question is, how different is polyester from nitrocellulose in terms of tone, aging, durability, etc.?

 

 

Tone - There is no difference in tone [iF] they are both applied the same thickness. Both of these finishes lay on top of the wood and they are not absorbed into the wood. The key to any finish is in the application by keeping it to an absolute minimum thickness. The end result will be a wash [iF] they are applied properly. Nitro is the thinnest finish and builds the slowest while spraying. It takes twice the coats of nitro to equal the thickness of poly or urethanes because they have a much higher solid content in the formulation.

 

Aging - Nitro can cold check as it ages. The older nitrocellulose lacquers had less plasticizers in the formulation and therefore would not flex as the wood moved due to heating/cooling or water exchange during the seasons. All instrument grade finishes are formulated to be somewhat flexible.

 

Durability - Polyurethanes, Urethanes and UV finishes are much tougher and scratch resistant than nitro with nitro being the softest of those mentioned finishes.

 

Repairability - Nitro gets a huge advantage in this category. It is easily repaired because the newly applied nitro finish will "burn in' or melt into the previous finish layer. The other finishes are chemically or UV cured and NOTHING will burn into the previous layer once the finish has "kicked" or hardened. You have to abrade the substrate in oprder to create a mechanical bonding surface for the new finish. They can be spot repaired with superglue but it is tough to do.

 

Cost - Nitro is the least expensive finish of the group to purchase. At least 1/4 of the cost of the other finishes. They all take the same amount of labor to apply and buff out so I don't understand the up charge for nitro. UV finishes require expensive $$$ lights or special ovens to cure the finish so they should be the highest cost to apply.

[Freeman Keller]

Two quick questions, Tim

 

What do you use?

 

Do you have any experience with the water based lacquers?

[dave251]

Nitro is more expensive because of the cleanup after the job is done...it's the nastiest to the environment. AND, buildiers feel like they can charge more for it; it's been around long enough to achieve "cult status" with the collectors. It's actually easier to buff out than the more modern polyesters(think mid '70's Fenders)....polyurethanes buff out readily. There are advantages to each finish, but the modern cross linking polymers will be the established finishes over the next few years, and WATERBORNES will eventually take over the industry, due to ease of cleanup, and environmental friendliness. As near as my experience tells me, the current advantage of solvent based finish VS waterbornes is that the solvent finishes "flow out" better upon application, allowing shorter work during final sanding and buffing. I use waterbornes for their reduction of harmful vapors...

 

BTW...those "satin" finishes are actually gloss with the addition of a "flattening paste". It helps the flowout of the spray, and evens the depth of the coat while reducing the reflectiveness....

[Freeman Keller]

 

As near as my experience tells me, the current advantage of solvent based finish VS waterbornes is that the solvent finishes "flow out" better upon application, allowing shorter work during final sanding and buffing. I use waterbornes for their reduction of harmful vapors...

 

 

My limited experience with waterborn on two instruments is that it didn't polish to quite as high a gloss and it can give "witness lines" between coats if you don't prep each coat carefully. Nitro softens the previous coat and flows each coat together, waterbase doesn't. It is sure easy to work with, however.

 

Nitro was somewhat easier to level - from my old hot rod days most of a lacquer paint job would end up on the garage floor. I honestly haven't decided what I will use on my next build.

[JerseyGuy]

I tremble to say this to Freeman, the star of this forum as far as I'm concerned, but I toured the Martin factory in Nazareth, Pa. a few weeks back and they have these really cool robotic polishers to do the glossing bit. Each polisher is in an enclosed booth with windows around. A tech puts six guitars in slots and a robot arm with four suction cups picks up in tuirn each guitar and holds it against an enormous spinning polishing wheel. After polishing every part, it returns that instrument to the slot and picks up another. So at least as far as Martin is concerned, there doesn't seem to be any hand-polishing. My second favorite part of the tour: a remote area behind a couple of screens where they had just heaved the truly unfixable guitars. Big pile of smashed fancy wood boxes and necks. Who wants that job?

[Freeman Keller]

I've seen the robot polishers (and robot spray painters) along with cnc neck mills in a vid. In my garage I have a couple of drills with lambs wool bonnets and a spray booth make out of an old guitar shipping box, along with a couple of dull rasps. But my guiars are "hand made" LOL.

[tim Mcknight]

 

Two quick questions, Tim What do you use? Do you have any experience with the water based lacquers?

 

 

Hi Freeman,

I am using McFaddens catalyzed Urethane lacquer. I love it.

 

Yes, I have dabbled with waterbornes and they just aren't there yet. I have used 5 or 6 different brands / formulations. As you mentioned witness lines are a problem, they are fussy about sterate contamination, they don't dry as hard, they are tougher to clean out of your gun because the liquid coagulates in the orifices and it is easy to get a bluish haze by the introduction of water into the air stream (you need a good in-line dessicant filter). A water seperator is not good enough. They are tempermental when spraying in high humidity conditions too.

 

Dave251, I clean nitro, poly and Urethanes out of my guns with hardware grade lacquer thinner. I don't find any one harder to clean the gun than the other. YMMV though. Nitro is under $30.00 per gallon vs. poly and urethanes at $120.00+ per gallon. I actually get twice as many guitars from a gallon of Urethane compared to a gallon of nitro.

 

Nitro is a pain to sand (dry) up to about30 days because it will gum up sand paper in a New York minute. Poly and urethanes will powder up in 24 hours and there is no problem with clogging the sandpaper. all three of these finishes are highly toxic and proper PPE should always be worn when spraying any of these finishes (including waterbornes).

[Hudman]

Tim,

Thanks for the pro insight on the finishing process. You killed a few myths.

 

[bbarkow]

 

Many moderately priced guitars are satin finished - in some cases it will be exactly the same product used on gloss guitars, they just won't have the final polishing (which involves a lot of hand labor and thus runs the cost up).

 

 

I found out from buffing out a satin guitar that a matte finish is also used to cover up sloppy sanding and dings.