As a guitar builder, I've tried about all the different finishes there are and have my preferences, but what do you like? I put up a poll, but I would be interested in your comments as well.
In the poll, please indicate in the first two items if the type of finish is important to you in choosing a guitar. From the next four items, choose the type of gloss you like AND
from the last seven, the type of finish material you prefer.Lacquer:
The industry standard, highest gloss, best protection. In the poll, I did not distinguish between the various kinds of lacquers as they all look pretty much the same, but these days lacquer could be nitro cellulose, acrylic, urethane, catalyzed polyester. Which lacquer to use is usually more about the builders resources and production requirements. All offer excellent protection, some people think the gloss looks "factory", especially when thick. Some people feel lacquer, especially if thick dampens the tone, though this is debatable. Nitro does not age all that well, can crack over time. I recently used a urethane lacquer that is unbelievably hard and can be buffed the day after it is applied. In fact, if not buffed within 24 hours, it takes all day to buff it (don't ask how I know this
) Great protection though and looked great. Lacquers are moderately difficult to repair as long as the lacquer used "burns in" well, not all do. Often easier to spray and buff the whole panel than to spot repair.Varnish:
A traditional finish. Moderate gloss, does not polish up as high as lacquer, but close. Excellent light refraction which means it really looks good, good protection against moisture. Not as hard as lacquer, but better protection against dings than French polish or oil. Slower process to apply, slower to harden up good for polishing. Typically, does not look as thick as lacquer, even when fully pore filled. Ages very nicely. Moderately easy to repair.French Polish:
A traditional shellac finish, very thin. Standard finish for the highest quality classical guitars. Excellent sound transparency. Can be brought to a very high polish, a matte finish or anywhere in between. Can be fully pore filled or left with pores showing, a matter of taste. Finish is reasonably hard after about a year, fairly soft in the first year however. In the first year, quite susceptible to dents, scratches, moisture and especially perspiration damage. Ages well. Very easy to repair. French polish can be used to repair most other finishes.Matte finishes:
Usually a sprayed urethane. Good protection and durable, less showy than high gloss lacquer. Can be fairly thin as it does not have to polished. To some people, however, it still looks like a factory finish. Factories like it because it does not show flaws like gloss and does not have to be polished out, saving time. Usually used on lower cost instruments. Hard to repair.Oil finishes:
Any number of oil finishes mixed with any number of ingredients. Some oils include tung oil, linseed oil, walnut oil, Watco Danish Oil. Added ingredients might include beeswax, stains, etc. Attractive when first done, but tends to collect dirt and dust and becomes dull rather quickly, but this may be the preferred look. Can be wiped down with more oil from time to time to refresh the finish some. Offers very little protection to the wood, but high sound transparency and a nice hand feel. Quick and easy to apply, very low cost.Antique:
Make a new guitar look old. Some people love it, some think it is kind of hokey, but it is certainly an option to consider. Materials used are carefully guarded, so who knows. A lot of them seem to involve irregular stain, French polish with various distress and wear marks.
Any others? Let me know what you think.
have you tried dammar Craig?
I like FP but have not been able to get the guitar body to hold up to perspiration where the arm rests on the lower bout. Mostly on the side, but a little on the edge of the top where the arm overhangs as well. No trouble anywhere else though and for necks, it works really well, both in application and in use. An FP neck plays well. I like a base coat of varnish first for even color and better light refraction. I've used full varnish on the b/s and FP on the top, but I still get some perspiration damage on the top if it is FP only.
I don't know about dammar, just looked it up, appears to be mostly used as an artist's varnish. Have you used it? I've used two varnishes, a marine spar varnish (Captain's) and Behlen's Rockhard. I like Captains better aesthetically, but it takes a month to harden up before leveling and even then there is some moderate shrink back. Most varnishes are not hard enough to take a super high gloss, but I like the glow they have when polished and I love the way they refract the light, really highlights the wood.
Oiled necks are really nice, IMHO, but my all time favorite neck is on Selmer 862, solid rosewood, and the nicest feeling neck for my taste, that I ever ever played. Craig, you've looked at it, so you probably know what the finish is. It almost feels like naked wood, but I do think there's some think protection on it.
I looked at it, but I wasn't really thinking about the finish. I did look at neck, mostly to look at the rosewood grain. My recollection is most of what finish there might have been was gone making it mostly hand on wood.
Amongst classical guitarists, unfinished Gabon ebony neck shafts, or at least ebony veneered neck, just the shaft portion are the hot lick.
Two Assumptions I have made but don't know are that a heavier lacquer finish alters the sound in a negative way, as opposed to a french polish which would sound better. BUT the lacquer protects the guitar more, and will increase it's lifespan, which is especially important if you have a guitar like mine (an alta mira) which has a VERY steep neck angle, causing higher tension in the strings and ultimately a shorter lifespan.
I ask this because I have been considering having the lacquer stripped off of my Alta Mira and replaced with a french polish. Would it affect the sound ? would it shorten the guitar's lifespan...
You get the gist.
One has to be careful making broad statements about the science of acoustic guitars, but I think it is safe to say that mass in a top that does not contribute efficiently to stiffness is not of much use. Finish can stiffen the wood, which is good in small doses, but at a certain point the addition of mass overcomes the stiffening benefit.
I can notice some tonal difference between the unfinished guitar and finished, and more than once I thought a guitar sounded better in the white than finished, but I don't personally hear "dramatic" differences, certainly not the kind of thing one would hear on the band stand or make me want to strip the finish. Most custom builders are careful to not make the finish, especially on the top, any thicker than need be. If the finish thickness gets out of control however, yeah, it makes a difference.
A finish that protects well against quick humidity changes, drinks being thrown in your face while playing (drink-in-face scene, take #2: "You slept with her, didn't you! [SPLASH]"), abrasion, dents, dirt, etc will contribute to longer life. Gypsy jazz guitars are lightly built and lead a hard life even when taken care of. A durable finish is a plus.
I can't see a connection between the finish and the neck angle. I don't think neck angle increases string tension which is a function of the string mass (gauge), length and tuning pitch. If the steeper neck angle results in higher break angle of the strings over the bridge, then the downward pressure on the bridge is higher. I can see how this might lead to shorter life if the guitar wasn't built for it, but not how this in turn that would connect to the finish.
People do this more frequently than you might think and they always seem pleased with the results. Some of this must be true, but some I suspect at least some is the enthusiasm to be expected after so much effort. If the top finish is really thick, refinishing would indeed likely make some difference. The tonal affect of refinishing the back, sides and neck would likely be negligible. Consider just stripping the top and French polishing it.
Be aware that if you remove wood when you strip the finish, you will reduce the stiffness of the top, for better or worse. The stiffness of a piece of wood varies as the cube of the thickness and removing a little bit of wood can make a significant difference in its stiffness and sound. 0.2mm to 0.3mm is 10% of the top thickness.
the difference on sound producing between the most and least dampening of finishes, if applied correctly and of about the same thickness, was very subtle though; these results were supplied by audio analysis, and not listening tests - so basically that concurs with Craig´s experience. dammar gives a beautiful look to the wood, it really "pops" the grain but it´s only soluble (to my knowledge) in turps, so the film takes a long time to dry (and even longer to cure), i´ve only applied it in little pieces and on scrap, not on full guitars, and really liked the effect. used it before doing the FP and it really added shimmer and depth to it - or was it wishful thinking?
all the best,
edit: P.S. - Craig, my offer for some BRW veneer still stands, if you´re interested.
Interesting... Okay, so then I have a mystery on my hands
I have 2 guitars, one is an alta Mira M01 which is a 670mm scale, and a Gitane DG 300, which is a 680mm scale.
I have BOTH strung with Argentines the heavier gauge, yet there is a very noticeable difference in string tension between the 2 guitars, the Alta Mira having the higher tension of the two.
I assumed it was because of the neck angle, which is very pronounced on the Alta mira, so much so that the bridge is almost a 1/2 inch higher than the Gitane, but the action is basically identical.
Given these factors, why does the gitane have such a lower string tension ?