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I used Tried & True Varnish Oil with moderate success on an electric guitar.  The stuff takes an eternity to cure, and my best results were obtained by mixing some of the varnish oil into a topcoat of 2# shellac and applying it like french polish.

My most recent instrument was finished with Waterlox over a shellac-based tint coat.  I was reasonably happy with working qualities of the varnish, and I ended up using micromesh and buffing it out with carnuba wax for a semi-gloss glow.  All in all, I like the feel of the T&TVO/shellac much better, despite the long cure time.  The Waterlox simply feels more "plasticky."

The Sutherland Welles products are the closest thing I've seen to the T&TVO in a tung oil-based product.  They're supposedly faster drying and won't discolor over time like the linseed base does.  However, their product line is confusing to me.  I've contacted the company with questions before, and they seem to take the attitude that you can't go wrong with any of their products.  Maybe that's true, or maybe it's hyperbole, but  I'm leaning toward the Murdoch's resin line.

My question boils down to what products have you used, and would you do use them again?

-Ben

One thing about Tried and True (I use it a lot, but mostly on things other than guitars) is that you have to wipe it off THOROUGHLY. The wood should feel dry when you finish wiping it off. This way, you're leaving just a whisper thin coat which will cure with exposure to oxygen in a reasonable amount of time. Each coat must cure before you add more. There are no solvents or driers. You probably already know all this. I've used it, with results I'm very happy with, on fretboards.

A lot of people use Tru-Oil on guitars and like it. I've experimented with it a little on necks and I'm not completely sold on it yet. So, I, too, am very interested in learning about other polymerized oils and oil/varnish blends for use on necks (and possibly on electrics, if I ever build any). Haven't tried Sutherland Welles, but their products sound like they may be good options. The various formulations sound like either pure polymerized tung oil with solvents and driers added, or oil/varnish blends (also with solvents and driers added). Some of them may be straight up varnish, I'm not sure.

You're a materials scientist, so I'm sure you know that Waterlox is, indeed, a varnish (as you said) whose main (only?) resin is phenolic. Apparently the phenolic is cooked with tung oil to make the varnish, but, despite the misleading labeling, the end product is not an oil nor an oil/varnish blend* - it's varnish.

*You know this stuff, Ben, but others may not: Varnish is made by cooking oils and resins together. The cooked product is no longer oil, it's varnish. If, AFTER the varnish is made, oil is then added to the varnish, the product is an oil/varnish blend. Solvents and driers are also generally added to all of the above. Tried and True makes the only products I know of that do not have solvents and driers added.

_________________
Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

Hi, Todd,

Thanks for your replies here and in the other thread.  You're right that both the T&TVO and the S-W products are more appropriately categorized long-oil varnishes.  Like you, I've had some success using T&TVO on a pau ferro fretboard.  The other application was with a mahogany neck and an ash body, so part of the issue I had was with pore seepage.  I wasn't trying to fill the pores, but that's how it eventually worked out.  I had to learn the hard way it seems....

Anyway, even with vigorous rubbing and thinning, the batch of T&TVO I have still takes awhile to fully harden.  It loses tack after 24-48 hours and can be recoated, but to build any sort of film thickness takes a really long time.  It's almost as much work as french polishing.

I was pretty happy with the shellac "composite" idea, which essentially substitutes the varnish for walnut oil in the LMI recipe (2 tbsp/pint).  The outcome was good for a wiping situation, and I may stick with it, but it will never produce a high gloss.

With the S-W product, I'm mostly curious how it works as a brushing varnish.  There is some solvent, but the solids content is the highest on the market for a tung oil varnish.  There are some added driers, but they are supposed to be safer the usual chromium variety.

-Ben

[QUOTE=Todd Rose]   
....*You know this stuff, Ben, but others may not: Varnish is made by cooking oils and resins together. The cooked product is no longer oil, it's varnish. If, AFTER the varnish is made, oil is then added to the varnish, the product is an oil/varnish blend. Solvents and driers are also generally added to all of the above....[/QUOTE]

Todd,
Cooking oil and resin together to make an oil varnish has largely gone the way of the buggy whip. This manner of making varnish was largely for natural resins like fossil copal, etc. The polyurethanes and alkyd oil varnishes we have today are cold cut, i.e. resins, oils and solvents mixed together just as we would make an alcohol spirit varnish. I wish someone was making a cooked short-oil, natural fossil resin varnish these days, but it is an art that has vanished due to cheaper alternatives becoming accepted in the marketplace.

_________________
Stay with the happy people.
--Reynolds Large

TRein,

Thanks, I was hoping that if I said something incorrect, somebody would correct me. I'm here to learn (and share what I can), not to be right.

Now, I don't mean to challenge or argue, but it is interesting that what you are saying contradicts information I've gathered from other sources. I am by no means an expert on the subject, just a woodworker and avid reader who tries to learn as much as I can about the materials I work with.

So, modern varnishes are "cold cut"? Can you point me to any sources of info on this process? There must be something about the making of the varnish itself - the way the oil and resin are combined - that is a chemically different process than what happens when you simply mix more oil with varnish. In other words (remember, I'm not a chemist, so bear with my imprecise language), when a varnish is made, it seems there is a chemical combination of the resin(s) and oil(s) that results in a product that behaves like _varnish_, that is, it cures hard. My understanding was that this chemical combination is accomplished with heat. By contrast, if you take a varnish (oil and resin chemically combined) and simply blend in some more oil (a drying oil, of course, or even a polymerized oil), you get an oil/varnish blend which will not cure hard - it will cure, but it will remain quite soft by comparison to a cured varnish, and will therefore perform quite differently.

An "oil/varnish blend", as I understand it, is a different beast from a "long oil varnish". A long oil varnish is made by combining relatively larger amounts of oil with the resin(s) to make the varnish (whereas a "short oil varnish" uses less oil). Both long oil and short oil varnishes are straight up varnish and cure hard, though short oil varnishes cure harder than long oil varnishes. An oil/varnish blend cures much softer than both of these and cannot be polished to a high gloss.

BTW, Ben, I believe the Tried and True Varnish Oil can best be described as an "oil/varnish blend" rather than a "long oil varnish".   

Everything I'm saying here is based on a combination of my observations of products I've worked with and information I've gathered from various sources. One of my primary sources is Bob Flexner's book, Understanding Wood Finishes. Please, TRein, Ben, anybody... correct anything I'm saying that's wrong, and, if possible point me to your sources of information. Thanks.

_________________
Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

Todd,
Several years ago I researched exhaustively various types of oil varnishes. This entailed talking directly with the chemists at varnish manufacturers. I must have talked with at least 6 people who formulate their company's products. All the varnishes were cold cut, i.e. no running of the resin and incorporating oil into the liquid resin. There are various chemical processes that allow incorporating resins and oils together without heat. These are probably out of reach technically for us individual luthier types. I know I have no interest in figuring out how to dissolve cheap modern resins into a varnish. The chemists I talked with (this was about 15 years ago) usually remembered an old guy in the company who knew about running resins and oils and making cooked varnishes. These old timers were long retired and with them went the end of an era. There are a few specialty varnish makers who are still cooking varnishes for the violin trade, specifically fossil amber varnishes. These are too supple for guitar varnishes, IMO. I have xeroxed the chapters of an old book that details how varnish makers used to make natural resin varnishes pre WW1. It is fascinating reading and makes me envious of the choices wood finishers used to have in varnishes, from waterproof coach varnishes to church pew varnishes that would not stick to the sweaty congregants clothes!
--Tom

_________________
Stay with the happy people.
--Reynolds Large

I don't know about most manufacturers, but I'm fairly certain that the Tried and True products are cooked in an anaerobic environment to build up the molecular weight of the oil.  This is how the oil is pre-polymerized.  I can't imagine any reason why they'd want to do a solvent exchange before cooking the oil and alkyd resin together.  It's too much extra effort and generates hazardous waste.

These old-fashioned varnishes are rather expensive and don't generally receive good reviews in Fine Woodworking or the like.  I like them anyway.

-Ben

P.S.  I forgot to mention, Todd, that I tried the Birchwood Casey stuff on a non-guitar project and didn't much care for it.

Oh, yes, and Flexner's book is my own best source of finishing info, too.  It's been awhile since I've read the varnish chapter, though.  Thanks for the correction, Todd!

-Ben

[QUOTE=Ben Furman] I don't know about most manufacturers, but I'm fairly certain that the Tried and True products are cooked in an anaerobic environment to build up the molecular weight of the oil. This is how the oil is pre-polymerized.
[/QUOTE]

T & T products are unique, in that they don't use any solvents or driers at all. They do heat the oil and call it polymerized, but their products don't behave like other polymerized oil products. Actually, the only other polymerized oil product I've used myself is Tru-Oil, and the only other widely available one that I know of is Sutherland Welles. Both of those contain solvent(s) and drier(s). How, exactly, T & T makes their "varnish oil", I really don't know. I've been to their shop, which is about a half hour from where I live, and the guy who owns and runs the place (it's in like a big garage) is not very forthcoming with his trade secrets... I did see his cook pots - big, but not huge, not very high tech looking at all, and I'm not at all sure there's anything anaerobic about it...

If you try any of the Sutherland Welles products, please tell me about your experience with them. I'm especially interested in the one that is pure polymerized tung oil with solvent and driers added (i.e. no resin content). One of these days, I'll get around to trying it myself - maybe it's the cat's pajamas for necks (for those customers who love oiled necks)...?

_________________
Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

Since the market is limited, I'll probably go ahead and just try the Murdoch's.  Since that product has resin, I'll consider it primarily as less toxic alternative to the Waterlox.  I'll write about it here, although I'll probably try it on a few things around the house before using it on a guitar.

I'm also curious about the Livos product line, but that will have to wait for another time!

-Ben

[QUOTE=Todd Rose]...when a varnish is made, it seems there is a chemical combination of the resin(s) and oil(s) that results in a product that behaves like _varnish_, that is, it cures hard. My understanding was that this chemical combination is accomplished with heat. By contrast, if you take a varnish (oil and resin chemically combined) and simply blend in some more oil (a drying oil, of course, or even a polymerized oil), you get an oil/varnish blend which will not cure hard - it will cure, but it will remain quite soft by comparison to a cured varnish, and will therefore perform quite differently.


[/QUOTE]

Okay, after looking around on the 'net and poking through some books, I think I've got this varnish formulation figured out.

In the old days, vegetable oil was simply cooked with amber.  This served two purposes:  it partially polymerized, or "cured," the oil and solubilized the amber.  There really isn't any chemical reaction that goes on between the oil and the amber that I can find.  The thick goo had to be dissolved in turpentine to make it usable.

Later on, "modern" resins arrived on the scene, like phenolic (phenol-formaldehyde), alkyd (phthalic polyester - akin to soda pop bottle plastic), and urethane.  These also do not "react" with the vegetable oil but merely dissolve in it.  The blend nevertheless requires heating to combine the two unless a stronger solvent is used.  If a strong, volatile solvent is used, then both the resin and the oil can be combined in it at low temperature, and the low-boiling solvent can be pumped away.  The finish hardness and gloss depend mainly on the total proportion of resin and its inherent hardness.  Phenolics are the hardest; urethanes are the most scratch resistant; alkyds are the least likely to discolor or blush.

Oil/varnish blends are simply varnishes that have been diluted with fresh oil, which has not been pre-polymerized and so has a lower viscosity.  It seems to me that the T&T products shouldn't fall into this category, else the cure time would be even longer than it already is.

Most manufacturers want the lowest viscosity possible with a given solids content.  Thus, it is in their best interest to use unpolymerized oils so long as oxidation catalysts (driers) are being added to accelerate the cure anyway.  (The downside to catalysts is that they are toxic and have a limited shelf life.)

Pre-polymerized formulas naturally have higher viscosity and require either more solvent or a different technique to apply them.  Higher resin content also require the use of cosolvents, such as mineral spirits and aromatics, to keep the resin from settling out.

***

I also found some info in the Sutherland Welles "flooring" pages that I had not seen before.  The Murdoch's line requires two separate applications of completely different materials.  The base coat is a penetrating tung oil varnish with a low polyurethane content.  The topcoat is a pure spirit varnish containing urethane resins and other additives but no tung oil.  It is a hard, clear finish primarily by virtue of the separate topcoat.  The manufacturer claims that the topcoat bonds well to the underlying sealer.  I'm not sold on it, but it's an interesting approach.

-Ben

Thanks, Ben. I have to admit that I'm in over my head at this point. That is to say, the information coming from different sources seems mutually contradictory and I really couldn't even begin to guess what's really going on...

Everything you're saying makes sense, though, and, for all I know, you're exactly right. You seem to have a good handle on it.

I'm beginning to think I should give up trying to really understand or sort out the chemistry of varnishes, and simply run tests with the ones I'm interested in, basing my ultimate choices on my own observations of how each one behaves and performs, not whether they're supposedly this type or that type.

OTOH, knowing at least what kind of resin the varnish is made with should help predict certain results, e.g. that phenolic is likely to yellow the most. Unfortunately, I don't think it's always so easy to determine what resin(s) is/are in a varnish. For example, I've read that varnishes labeled polyurethane often contain both urethane and alkyd resins.

One of these days, I'll try the Sutherland Welles "Original", which I _think_ is nothing but polymerized tung oil with solvent(s) and drier(s), and see if that makes an excellent oil finish for necks. I'll let you know what I find.

_________________
Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

[QUOTE=Todd Rose]   

I'm beginning to think I should give up trying to really understand or sort out the chemistry of varnishes, and simply run tests with the ones I'm interested in, basing my ultimate choices on my own observations of how each one behaves and performs, not whether they're supposedly this type or that type.

[/QUOTE]

In fact, that's essentially what I've done up to now, though I keep thinking it'll be helpful to me to have a grasp on the chemistry. I guess that's just my curiosity more than anything. What really matters is how the stuff works.

_________________
Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

[QUOTE=Todd Rose]I'm beginning to think I should give up trying to really understand or sort out the chemistry of varnishes....
[/QUOTE]

Dear Todd,

I hope I haven't contributed to your confusion and frustration!  The definitions seem to have evolved over the years.  "Varnish" can mean many things to many people, or so it seems....

Trust Flexner and Jewitt.  Other sources are suspect.  I'm still troubled by web site I ran across suggesting that alkyd resin is made by adding a chemical directly to vegetable oil.  Without belaboring the details, I can't see any way this would result in a polymer.

The bottom line is always how the stuff works in practice.  The only value in understanding the underlying material is when you want to make an incremental improvement in your result by changing to a different formulation.  Since nobody wants to disclose exactly what they're selling, this becomes frustratingly difficult.  S-W is pretty frank about their products, but you still have to read between the lines.

There are two downsides of polyurethane: optical clarity and UV resistance.  Some manufacturers have switched to "modified" polyurethanes, which I can only guess are admixtures of other resins.  It's possible that someone has invented a copolymer with urethane "segments," but that seems unlikely to me.  S-W admits to using a simple mixture of urethane and alkyd (polyester) resins.

"Spar" varnishes are virtually guaranteed to contain phenolic.  It is the hardest wearing and resists UV breakdown.  The downside is that it turns yellow with UV exposure.  (The Waterlox High Gloss that I used was formulated with a phenolic.)

No matter what the resin is, they all improve the wear resistance and moisture resistance of the base oil whether it's pre-polymerized or not.  The more resin, the better the protection and the harder the repair.  It's a direct trade-off.  I've decided to try the S-W wiping varnish first because of its balance of repairability and hardness.

-Ben