Quote:
Originally Posted by lizzard
Looking forward to seeing yours come alive and seeing your feedback, esp re the French polish.
|
Given the goals for this guitar and the build style Tom likes to use, we decided to maximize our chances of hitting the target voice with a whole-body French polish finish, my first.
More than one luthier has told me that the best-sounding guitars are built right on the verge of implosion, with the thinnest of finishes and
just enough wood, bracing, etc. to maximize tone, responsiveness and resonance without structural failure. Knowing from the outset that this guitar would have a French polish finish allowed Tom to build as lightly and 'close to the edge' as possible.
I’m pretty careful with my guitars and wasn’t worried about French polish's reduced resistance to dings compared to lacquer, but I had heard that some player’s skin chemistry could damage the finish, so I asked some French polish experts about how concerned I should be.
Eric Reid, who is highly respected for his finish work wrote:
It's true that some players' sweat attacks shellac. I've been doing this for about twenty years, and I would say that it is an issue with less than 5% of the population. I don't believe it correlates with how much you sweat, but rather with your body chemistry. If I had to hazard a guess, I would say that alkaline sweat would be the issue. (Household ammonia breaks down shellac, whereas vinegar doesn't.) The symptoms are these: first, the shellac becomes cloudy in the areas it contacts the body (not the neck in my experience, but on the back and sides and top where they touch the chest, and right arm); then the finish develops a fine cross-hatch pattern; and finally, the finish becomes gummy. The repair is straightforward: some light sanding, and French polishing over the affected areas. After the touch-up, the finish looks like new. To prevent further damage, a seal-coat of a drying oil seems to do the trick. So why not add the seal-coat from the start? Three reasons: The problem is fairly rare; drying oils, however thinly applied, add a bit of sound damping; and the final gloss is not as high as can be achieved with French polish alone. I have French polished several of Leo Buendia's guitars, a few of Tom Doerr's, and dozens of Ervin Somogyi's. None of these have had an issue with the player's sweat attacking the finish. The few examples I've seen have been with the classical guitars that constitute the majority of my business. Over the years, I've met a small number of players whose sweat aggressively attacks shellac. In each case, the repair was simple.
Obviously, the top of the guitar produces most of the volume of a guitar's sound. The back and sides and neck add tonal color. The degree to which the back and sides contribute to the tonal color of the instrument depends to a large extant on how the guitar is designed and built. Lightly built guitars, with their "responsive backs" get quite a bit of their tonal color from areas other than the top. For what it's worth, when I began doing work for Ervin Somogyi, I was just French polishing the tops of his guitars. The back and sides were sprayed with lacquer. After he heard the sound of one his guitars French polished over the entire body, he switched to having that be his standard finish. We do the vast majority of his guitars now. Leo Buendia and Tom Doerr both believe that French polish on the back and sides as well as the top results in the best sounding instruments.
For those who are unfamiliar with French polish, it uses non-toxic, natural materials that you could safely consume if you were so inclined. Here’s a description from Ben Lambdin, who will be applying the finish on my Doerr:
"French Polish" is not a finish itself, but rather an old world technique commonly used with a Spirit Varnish (natural resins dissolved in high proof grain alcohol). Like a pair of expensive selvedge denim jeans, a French Polished Spirit Varnish finish will wear uniquely to the player, and it can be restored to its original state by someone with the expertise.
My finishes are as natural and organic as possible - using pumice stone and the wood's natural oils to fill the open pores, natural shellac (a secretion of the lac beetle) homebrewed with 192 proof grain alcohol to seal and build a foundation, and a mix of shellac and other natural plant resins with organic walnut and/or olive oil for the final polished top coats.
Here’s a pic of some of Ben’s materials. I’m not sure I’d want to eat the shellac flakes, but that bottle of Polish vodka? Well…
