An Oil Varnish Thread...

[capohk]

Hi all

As a small-shop builder I have tried finishing my guitars with first French-polished shellac, and rattle can nitrocellulose lacquer. Although I have had reasonable success with both, I would like to try a brushed oil-varnish finish.

I know there are several high end builders who use varnish so it is undoubtedly a legitimate method.

I would like to start a thread where advice on materials and process can be put in one place as a resource for myself and others trying this out.

I live in Hong Kong so air freighting flammable materials is difficult, hence I think it's useful to say where things are available.

MATERIALS:

So far, recommended ready-made varnishes are:

Tru-Oil - easy to apply, a softer finish
Ace Hardware (USA)
Liberon Finishing Oil (UK) - Kevin Aram uses this for his classical instruments

Epifanes (Netherlands and elsewhere) - Laurent Brondel has developed a formulation involving 1-1-1 mix of Epifanes clear varnish (a long-oil varnish) with Epifanes accelerator (extra resin) and Epifanes thinner.

I'm really interested in any other commercially made ready-to-use short-oil varnish brands. The more choice we have, the more likely people can find them...

Apologies/props in advance to those I have name-checked. Please correct me if I have got anything wrong!

[capohk]

PROCESS:

It would seem that some sort of sealer coat is necessary, especially on oily woods. I think most of us would want to grain/pore fill backs and sides as well so I think I will start with a shellac/pumice filler. I have also read about egg-white and I have used epoxy as a grain fill with some success, but for my purposes the shellac works well.

Having sealed and filled with the shellac, I think I will brush 3 - 4 coats with a drying period of 24 hrs between coats. I think it would be sensible to sand back between coats, probably with something like 320 grit paper.

For short-oil varnish, some report that it is hard enough to buff after 3 days, but I have no particular time pressure so I would plan to leave it to harden for around a month before progressive sanding back to 2000 and buffing. A month, give or take, for a finishing process is ok with me - I will get on with other building while I wait. I am sure for some it will be too slow.

Again - I would really appreciate suggestions on (and alternatives to) this process from those with experience.

[B. Howard]

Violin makers are the kings of oil varnish. The best all brew their own varnish rather than use commercial brands. And for good reason, most commercial varnishes are based on plastic resins rather than natural ones. Even most of the tung oil you buy at the wood work store is loaded with phenolic resins....

[redir]

I have only used it once so far but I like the results. I used Sherwin Williams FastDry oil varnish as seen here:

http://www.sherwin-williams.com/home...stdry_varnish/

The only thing I did was dilute it a bit in mineral spirits. It's a bit thick right out of the can. Very easy to use as brush on, drys fast, and has a nice look to it.

[Quickstep192]

I'm interested in learning more about the Sherwin Williams varnish. I've had very good success with their paint products, but I've never tried their varnish. I found two very polar reviews on the Sherwin Williams Website.


(1 out of 5)
Not like any varnish I am familiar with

November 09, 2012 by Woodsmith
It quckley becomes tack free, too quickly to permit proper tipping out. . This product does not level or build well. Although becoming tack free quickly the finish remains soft even after several days. Upon sanding between coats, the removed varnish smears off and balls up rather than creating sanding dust. The varnish never seems to become hard but remains soft, even after drying for a week at 72 degrees and 30% humidity. I do not know how this product could possibly be used for any surface that is subject to any contact during use (i.e. table tops, floors, cabinet doors, stocks, furniture). I do not believe this product to be true varnish. It is milky/translucent in the can, not tranparent like varnish. I have extensive experience applying various varnishes, including marine spar varnishes which require some skill to apply with good results. I have always achieved hard, mirror-like finishes with all previous varnishes I have previously applied, always using high quality natural bristle brushes. I suspect that, once again, quality has been seriously compromised in to comply with VOC regulations. I would not recommend this product for any purpose.. Anyone who has experience with true varnishes will be very dissatisfied with this product.
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(5 out of 5)
Good Stuff

January 11, 2011 by woodyb
This varnish is an excellent finish for acoustic guitars. I know that's not it's intended application, but it works great. It's durable, flexible, and acoustically friendly. Woody B Brackett Instruments

[Ned Milburn]

The builder who instructed me during my first build also built many violins. He uses oil varnish, and I believe he also uses a Sherwin Williams product.

The exact trouble with oil varnish is its length of drying time. Hence, an ultra-violet lighted drying chamber (a wardrobe, for example, lined with aluminum foil shiny side out) can help a WHOLE lot.

Correct viscosity is essential. I have not used oil varnish, but watched "my master's" brush technique. A high quality brush and good technique is crucial. I have used brush on water based lacquer to very good end, but again, retarder (to avoid drying too quickly) and even a touch of filtered (or distilled) water must be used to achieve the correct viscosity and dry time.

[redir]

The SW fast dry stuff is just that... fast drying. I never had a problem sanding between coats, not sure what could have happened to that one reviewer except to think he was reviewing a different product or perhaps working outside in humidity? I could not build it up to a gloss quite like lacquer but that's ok too.

[Bruce Sexauer]

I am surprised to learn that I have said Ace is harder than Rockhard as I do not recall thinking that. If I actually have written that I would like to retract it, so perhaps you could let me know where it is. Thank you in advance. I hope it is not in my schedule I have sent to so many of you. I haven't actually read that for a while!

In fact I think they are very similar in regard to hardness and work-ability, though perhaps not currently; it has been a while since I used Rockhard. I do not care for the color of Rockhard, nor the price, but especially it is that every time I bought some they seemed to have reformulated it significantly. I have been using Ace for nearly ten years and have seen no change in its character at all, though the price has gone up about ten percent.

[Alan Carruth]

I used Rock Hard Table Top varnish, until they changed the formulation. It was a phenolic resin varnish, now it's polyurethane. It's the third or fourth time I've had to find another varnish when the one I was using got pulled from the market. Right now I'm working with 'Murdoch's Ure-Alkyd Floor finish' from Sutherland-Welles.

Violin makers often work with much softer varnishes than we want for guitars. I can't tell you how many violins I've seen with fuzz from the case stuck in the varnish. If they make their own cooked oil-resin varnishes they probably end up with a product that's a lot more variable than you'd like. Strad's varnish was pretty variable too. Most guitar buyers won't put up with that now. You're probably better off buying a commercial product. Rather than rely on an import, I'd look for something local. That way you're not at the mercy of some other country's laws about VOC content or flammability or whatever: your own country will be bad enough in that respect.

Look around for 'short oil' or 'rubbing' varnishes. 'Long oil' or 'spar' varnish will tend to be too soft for guitars, and the high oil content that makes them that way tends to add a lot of damping. Spar varnishes also can get sticky in hot humid weather.

I like to use varnish straight onto the wood (after filling): it looks better. Some woods, particularly tropical ones, have non-drying oils that can slow the hardening of the varnish. Different varnishes seem to be affected by different woods, and even within a species some pieces will be more trouble than others. UV light can help in those cases - sometimes. Sealing the wood with shellac can help - sometimes. The only varnish I ever used that was 100% reliable on all woods was Mohawk's '4-Hour Rubbing Varnish'. They discontinued it...

[peter.coombe]

I have fooled around with just about every varnish I can get my hands on, but that leaves out just about all the oil varnishes produced in the USA because I can't get them. I just could not get good results with any of the locally produced varnishes which was very frustrating. Long dry times of the oil varnishes caused problems with dust and the occasional insect, and some clog sandpaper so it becomes almost impossible to get a level finish. I have been using Target Coatings EM2000 on my mandolins for many years and after all those trials and wasted time and money I keep going back to EM2000. It is a pain to ship to Australia because Target abandoned their international customers a few years ago, but I can still get it via a third party. Stew Mac abandoned Target Coatings products so that also threw a spanner in the works. Water based paints can still be shipped internationally, but oil based cannot be shipped via air without unbelievably expensive special packaging and surface mail no longer exists from the USA. EM2000 is softer than nitro, but it goes on thinner, is more flexible and buffs up nicely. I prefer a varnish finish, no nasty fumes and I think it makes a warmer and "looser" sounding instrument. Like many varnishes, EM2000 does darken to a light amber with age which I really like, but others might like to keep their finish water clear. I have had a small number of complaints from people used to Chinese bullet proof thick polyester, but hey, you bought a hand made and hand finished instrument made to sound good - look after it!

[capohk]

Hi Bruce - my apologies for misrepresenting you. I looked back at my notes and it was in fact Laurent Brondel who had made the comment about Ace vs Behlen. I will edit my original post accordingly. It sounds from what Alan Carruth says that the Behlen is no longer an oil varnish anyway so I'll remove it from my list.

Thanks for the rest of the feedback so far - I am looking at locally available formulations and trying to interpret the data sheets. I wonder if someone would be willing to help assess their suitability if I posted the links?

[capohk]

Peter - do you brush the em2000?

[Bruce Sexauer]

While I know that solvent based polyurethane is not considered a a varnish, it is not clear to me that is not as it works similarly and produces results virtually indistinguishable from the dozen or so more bonnefied varnishes I have used. I know of at least one high end respected and accepted maker who does use urethane as his primary finish. The usual negative criticism of urethane is that it is a plastic like film, has high damping, and subsequent coats do not chemically bond to previous coats, but all of these are characteristics of any oil varnish as well, so far as I am aware. Given that there is a very wide range of formulae and chemical principle accepted under the banner of "oil varnish", I wonder what keeps polyurethane from being included?

[Laurent Brondel]

Traditionally oil varnishes use alkyd or phenolic resins I would think.
Rockhard switched to a poly resin, so technically it is still an oil varnish (I assume they altered the rest of the formulation little) but can no longer be considered traditional.

Varnish can mean a lot of things, up to any finish that cures from polymerisation (rather than evaporation, like lacquer and shellac).

However, to stay in the traditional realm, I assume oil varnish to mean a finish composed of alkyd or phenolic resin with a mix of oils (tung oil for the best quality products) and solvents that polymerise into a solid finish. Short or long in oil for a harder or softer finish.

I do not think either Tru-Oil or Liberon Finishing Oil (a French product BTW) qualify as varnishes per se. They may form a relatively hard film after a long while, but they're oil finishes, not varnishes.

I agree with Al that the oil varnishes (homemade or not) violin makers tend to use are of a softer nature and unsuitable for guitar.

Good luck in your search, there are not many "real" oil varnishes out there, and doing the R&D can be time consuming and frustrating.
I've been using the essentially same Epifanes product for 7 years now, no discrepancy between batches (as Bruce and I experienced) and it is IMHO the best oil varnish out there.

[Quickstep192]

Laurent,

As I recall, you use Epifanes Clear Varnish, but I'm wondering if you've tried Epifanes' other varnishes like Rapid Coat or PP Varnish Extra for build coats?

Rapid Coat and PP Varnish Extra say they bond well to oily woods (good, right?), build thickness quickly and don't need sanding between coats. I'm sure this is mostly for building thickness on boat trim where leveling is less important than on a guitar, but quick build, and fast drying don't sound bad, so I'm wondering if you've experimented with these.

Also, would you mind sharing the proportions of varnish, accelerator and thinner (and japan drier) in your recipe?

Thanks!