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Laurent, are you referring to Waterlox Original or Waterlox High Gloss? From what I read on the website, it seems like Waterlox Original might be a semi-gloss.

Sweet. Please post the results of your experiment. I'd also request a section with nitro (straight onto the wood), and another with damar dissolved in toluene (or lacquer thinner), if it isn't any trouble. Epoxy would be cool too. Make sure you use enough of each that it just starts to build a film.

I do not use nitro, I think it's too darn toxic, doesn't age well, and doesn't look particularly good. I use mainly shellac and Rock Hard varnish, although I hope to be switching to a home-cooked natural oil varnish when I get it figured out. I use shellac and pumice for pore filling, although that is the part of my finishing process that I am least happy with. It's just the least bad thing I've gotten to work consistently so far. The normal opaque fillers will never touch one of my guitars. Damar and pumice does not work well, unfortunately. I've also tried adapting methods from violin makers, but those don't seem to translate well to real pores (as opposed to maple pores). I haven't tried epoxy, that would probably get acceptable results, but it's toxic and not natural. What I may end up doing is brush on a coat of thick damar, sand down to wood, and repeat until the pores are filled.

Good luck.

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Andrew Gamble
Sine Guitars
Custom Low-Impedance Pickups and Preamps
[url]sineguitars.webs.com[/url]

My method consists of wiping oil on and off before sealing, so there is certainly not a "bunch of oil" in the wood. Nor is there additional damping or oily surfaces to repair, just a very, very thin film sealed by a coat of shellac. As a matter of fact the guitars I've finished this way are the best sounding to date, and I do not attribute this to the finish.
OTOH this meme about oil varnishes being more penetrating than other finishes is simply not true. At least not with the hard varnishes suitable for guitars. Actually the main issue with most oil varnishes is poor adhesion: the film lifts easily from the wood, leaving a clean, raw surface. Hence the need of a sealer, whereas shellac or successive thinned coats of oil varnish.
Waterlox original, as recommended by Rick Turner. Of all the oil varnishes it has the best adhesion, actually it adheres much more than any sealer/finish I know, including shellac. It comes very thin in the can, and I've used it as a sealer only. Semi-gloss would mean it has flattening agents added to it, which seems unlikely. However it is so thin that it acts almost as an oil: to get a bit of body and gloss would require many coats. And no, it is not "penetrating" either.

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

I agree with you Laurent, about oil varnish, or shellac, or any finish "penetrating the wood" and damping it. Just doesn't happen.
Sure, you can layer anything on thickly and it will dampen, but the finish just does not "soak" into the wood very far, if at all.

I like to seal my woods with thin shellac, and I would like it to penetrate deep enough to increase adhesion of the later thickness of finish, but then when I scrape off under the bridge footprint and fretboard extension, it pretty much pops off at the wood surface.

I suppose if someone wanted to prove a point, they could soak a thin raw linseed oil all the way through a spruce top, if they wanted to....

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You just might be brushing and sanding for a long, long time. I've tried that technique and it's sloowww. Virtually all finishes shrink over time and there's always the added problem of bridging. Rockhard will probably work much quicker, although even that stuff will be a lengthy process.
I've also tried it with heavy padded coats of Shellac, sanding and leaving the powdery residue in the pores. It certainly works but again, a lengthy process.

Many of the Lute makers are now using Danish Oil straight onto bare Spruce. Used very sparingly. I've finished a number of soundboards with it. Doesn't seem to hurt the tone, although I guess it's pretty hard to be sure one way or the other.

Thanks, Laurent. I'm really looking forward to doing a few test pieces.

This is the finish Robert Lundberg uses in his book "Historical lute construction", and presumably traditional. He burnishes the oil (tung if I recall) onto the top with a piece of tough fabric.
Michael is right, not the best or fastest method. Even when the pores are completely filled, the finish will shrink some more over a short period and make the pores visible again. Oil varnish does not shrink like evaporative finishes do, far from it, but it still shrinks a bit. An alternative method is to seal, spray a few coats, and wet sand with varnish or oil (320 or 400). The slurry will fill the pores pretty quickly. It's best to let it cure a few days, or as long as possible, before levelling and continue with the finish schedule.

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

I have been using Waterlox as my first coat with good success. I have not tried Damar but it sounds like a nice thing to try, I will try to get some. I have not had any problems with it drying on any rosewoods but I use an ultra thin coat as the sealer coats. I have also had n0o problems with it in the can as long as I am very careful about using the Bloxygen. I have had the same can in the shop for maybe a year. If I miss one time, though, it will gel fast. I have also been using it as my neck finish, I love how it feels. It takes a lot of coats though. I have been rubbing them on.

With the waterlox I will apply it in 2 thin coats and then epoxy fill over it. Any sand throughs get touched up with another quick rub of waterlox, much easier then more epoxy (for me at least). I have not been doing it to the soundboards but may give it a try. I'll let Laurent try it first!

*Edit* I am by no means a super experienced finisher so please take my comments with that in mind. I have done a few semi-successful water based top coats but most of my experience in finishing has been French Polish.

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Burton
http://www.legeytinstruments.com
Brookline, MA.

I've done that, and it works fine. I wasn't talking directly about your method, I realize now that I should have been more clear about that. I was talking about using something like tung oil or varnish as a finish without a sealer, or in a quantity sufficient to be a good sealer.



The penetrating effect of oil varnish is well known in the violin-making community, and has been shown to be true by images from a scanning electron microscope. In my experience Behlen's Rock Hard varnish does penetrate noticeably on spruce. I do use it thinned to brushing consistency with turpentine.

Laurent, I may be misunderstanding here, but your tone seems very confrontational. I'm not fighting you, and I mean no disrespect, I hope you understand that. I like your work very much.



That's precisely why shellac makes a good sealer: it provides good adhesion without much penetration.

A few violin makers actually intentionally saturate the top with linseed oil. The oil is only applied unthinned to the outside surface, and when done, water will bead up on the inside surface. Most violin makers do not think highly of this practice.



I know, I've tried it using shellac. The trick is to totally saturate the alcohol with shellac, until no more will dissolve, so that it builds faster. I would also let the filler cure for a while before before proceeding with the finish. Still, it is a slow process. I'll probably end up using epoxy.

_________________
Andrew Gamble
Sine Guitars
Custom Low-Impedance Pickups and Preamps
[url]sineguitars.webs.com[/url]

I ordered the damar and a 2 oz. sample of Waterlox. I plan to order the Epifane's Clear as well. Lets just say I hate shipping costs.

I’m trying to decide how to structure the experiment. I plan to make 5x5ish squares of figured sapele and lutz spruce. The sapele will be filled with epoxy and sanded back to wood. If the goal is to see what brings out the most "glow", I wonder if I should just do a thin build, or go through the entire finish process to really see what the end result would look like? Could you imagine if we found one that had that Walker-esq glowing ora? Do these seem like appropriate options? Are some overkill? Are any blaringly missing?

Square 1: Nitro
Square 2: Vinyl sealer under nitro
Square 3: Damar
Square 4: Damar under nitro
Square 5: Waterlox
Square 6: Waterlox under nitro
Square 7: Waterlox under vinyl sealer and nitro (to see if the vinyl sealer is unnecessary)
Square 8: Epifane’s Clear Varnish
Square 9: Damar under Epifane’s Clear Varnish
Square 10: Waterlox under Epifane's Clear Varnish
Square 11: A layer of Z-poxy left on the wood

You are missing shellac. Other than that it sounds good, although it's possible that the epoxy filler may serve to equalize the results on the sapele more than we would want. I would suggest leaving the pores unfilled for this, so as to test only the refractive properties. You could then test the epoxy filler alongside the other stuff. Maybe even test paste filler just for a laugh.

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Andrew Gamble
Sine Guitars
Custom Low-Impedance Pickups and Preamps
[url]sineguitars.webs.com[/url]

From what I gather oil varnishes as used (or made) by violin makers are aeons from short/medium oil varnishes like Epifanes or Rockhard. They're applied much, much thinner, and the formulations are different. The few violin makers I know use a spirit varnish, a totally different beast. And speaking of spirit varnishes, Behlen's "Violin varnish" makes an excellent sealer for oil varnish, it is very clear and has great adhesion.
I do not know of scanning electron microscope images, if you can provide a link or a reference I'd honestly be curious.
Rockhard does not penetrate on spruce or WRC more than any other finish IME. I used Rockhard on over 30 guitars, and the ones built without oily woods I sprayed Rockhard directly on the top and back & sides without sealer. Same potential adhesion issues as with a shellac sealer, possibly worse: that should tell you about the penetrating abilities of Rockhard. Same experience with Ace Hardware oil varnish, Epifanes and Behlen water-white restoration varnish. They do not penetrate the wood anymore than shellac, lacquer or poly. Shellac, however, has terrific adhesion, so does Waterlox.
Not at all, and I apologise if I come up that way. I am perhaps a bit dry.
The issue (or should I say non-issue) of the penetrating power of varnishes comes up regularly, a position mostly defended by people without much experience with the techniques and the products.

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

My own experiment to see how much Truoil penetrated spruce with a wipe on, buff off, dry and build application indicates that there is little if 'any' penetration at all of the product into the wood.

As for long term storage of any product in its own bottle that is activated by oxygen, place marbles into the liquid as the product is used just before replacing the cap. This will displace the air in the bottle and keep the content at the brim so it cannot oxidize.

Cheers

Kim

Laurent, you've used Ace Spar varnish? How did it work for you? I've been wanting to try it, it's actually been recommended to me by some reputable violin makers, strangely enough. I'm guessing it would need some modifications in order to be guitar-worthy.

There's really not that big a difference between violin varnish and normal synthetic varnishes. It's all some kind of resin combined with drying oil and dissolved in a solvent. Violin varnish is some tree resin in linseed oil, Rock Hard is phenolic in tung oil (I think, though it may be polymerized linseed), Epifanes is phenolic and alkyd in tung oil, Ace is probably alkyd in an unknown modified vegetable oil. The oil lengths are not at all dissimilar. Also, violin varnish does not seem to be as thin as I would have thought (usually). It's certainly thicker than a good French polish job.

Behlen's Violin varnish is mostly shellac.

Lack of adhesion does not necessarily indicate lack of penetration. I'm not entirely sure how that works. My hypothesis is that the oil penetrates, but the resins do not. I cannot prove that, but I do know that pure oil penetrates and spirit varnish does not, so it makes sense to my mind. I'll try to dig up those SEM images, I'm not sure where I saw them. There are a few of old Italian violin varnish, and some of the cut end grain of spruce with known grounds and varnishes on it. Oil varnish can be clearly seen within the cell structure, while the spirit varnish does not go past the first cell walls at all.

Have you done any tests to prove that varnish does not penetrate? In my experience, spruce that has been finished with Rock Hard varnish and then sanded down to the wood continues to clog sandpaper after all the varnish on the surface is gone, indicating the presence of oil in the wood. I'm not saying it's saturated, but there is oil there at least 1/32" into the wood.

_________________
Andrew Gamble
Sine Guitars
Custom Low-Impedance Pickups and Preamps
[url]sineguitars.webs.com[/url]