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ORIGINAL: SephardRick

Interesting about how some of the big names of flamenco used Devoe guitars. I am surprised they are lacquered finished, instead of french polished.

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ORIGINAL: SephardRick

My concern was about the lacquer finish checking.

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ORIGINAL: SephardRick

That's reassuring about the lacquer finish.

I've had problems with older Gibsons arch-tops finished checking.

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Thats part of the character of old electric guitars IMO. Plenty of guys pay tons of money for relic nitro guitars.

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ORIGINAL: SephardRick

That's reassuring about the lacquer finish.

I've had problems with older Gibsons arch-tops finished checking. It nice to know a lacquer finish, if applied correctly, can endure sudden ambient temp changes.

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ORIGINAL: SephardRick

The most common were nitrocellulose lacquer sprayed over alcohol, turpentine, linseed, and paraffin based primer coats. We were told by the manufacture (Parks) any quick dry finish over a slow curing material would cause alligatoring or checking. Fisheyes in the finish from high humidity was another problem.

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ORIGINAL: jshelton5040

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ORIGINAL: SephardRick

The most common were nitrocellulose lacquer sprayed over alcohol, turpentine, linseed, and paraffin based primer coats. We were told by the manufacture (Parks) any quick dry finish over a slow curing material would cause alligatoring or checking. Fisheyes in the finish from high humidity was another problem.

There's little doubt that using any finish involves a learning curve. Just ask anyone who's tried French polish for the first time. If you're going to spray lacquer or any other finish you absolutely must attend to water and oil in the lines, not to mention temperature, humidity, air flow, ventilation, etc. Otherwise you'll have constant problems with fish eye, pock marks, blushing, etc. I will never listen to advice from a manufacturer after my latest fiasco with cold checking. If I weren't so old I'd consider switching to polyester since I think it's the best finish available for the small shop builder.

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ORIGINAL: tri7/5

John, curious why you would entertain poly as a finish on an acoustic instrument? I've always felt, and many players agree in the electric realm, that poly is the most dampening finish out there. Since acoustic volume and reponse isn't the most important thing in the electric realm its kind of a moot point. However you can immediately feel the acoustic vibration difference and sound in an electric guitar finished in poly vs. thin nitro or satin etc.

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I've always felt, and many players agree in the electric realm, that poly is the most dampening finish out there

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I wonder whether the dealer made the same mistake I did, calling catalyzed polyurethane "lacquer?

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The overall appearance is a "gloss" finish but not like a factory gloss finish. Please do not expect perfection. My finish is as thin as possible to retain a good tone. I'll carefully buff the finish a bit more for you. I do not add wax, the shine is obtained by liquids (buffing compounds) containing micro abrasives.

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ORIGINAL: Richard Jernigan

One of America's best known luthiers, who has seen the Arcangel Fernandez, points out that the finish is NOT lacquer, it IS catalyzed urethane, a much more durable finish.

Lacquers dry by evaporation, and in fact usually do eventually crack or check. Catalyzed urethane hardens by catalyzing the long chain molecules of urethane. It is a much more stable finish.

Catalyzed urethane takes more skill to prepare and apply than lacquer. Thus many American factories apply lacquer to instruments, despite its inferiority to catalyzed polyurethane.

The catalyzed polyurethane on my '67 Ramirez 1a blanca is still in excellent condition, though the top shows a few small marks due to the softness of the cedar.

I knew the finish on the Arcangel was catalyzed polyurethane, but fell into the lazy habit of calling it lacquer. Devoe is a highly skilled luthier, no doubt familiar with the practices of Spanish makers. I wonder whether the dealer made the same mistake I did, calling catalyzed polyurethane "lacquer?"

RNJ

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ORIGINAL: encanto

But I've had strange experiences with a guitar or two with sprayed lacquer that, although fully dry, was super easy to accidentally penetrate with a (relatively short and soft) fingernail. It did not look like factory finish or french polish. This sprayed lacquer was extremely shiny (like a mirror) but also extremely thin and scratchable. Something as simple as passing your nail on top, without any pressure, would already cause a dull line on the surface when viewed against a light source. I remember I was extremely puzzled by what they had used, and whether they had cured it properly. French polish seemed way more durable in comparison, although I do share the opinion that the type of finish is less important to the sound.

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ORIGINAL: jshelton5040


So according to this you have either a polyester or acrylic finish.

"Two-component polyurethanes consist of a polyisocyanate hardener and a resin, either an acrylic or polyester. Once combined, they result in a highly cross-linked finish."

If lacquer is applied correctly i.e. in very thin coats it is not prone to cracking or checking. I recently examined one of our guitars built in the early 70's which has no sign of checking or cracking. With the exception of the recent mistake I made by following manufacturer's instructions I have never seen any cracking or checking in the finish on our guitars in more than 45 years so I think your statement "Lacquers dry by evaporation, and in fact usually do eventually crack or check." may be a bit of an exaggeration.