For the first time I'm experimenting with pure tung oil and need some advice, or perspective as such. I'm refinishing a M2 Springfield stock and have been using pure tung oil as I want to stay as close to original with this project as I can. I am not a fan of boiled linseed oil. So far I probably have about six coats on this thing with the last few being thin "skim coats" that were put on with my hands and allowed to dry. It takes hours for the coats to dry (no surprises here) and within something like one hour the coat will dry up or soak in and go real dull. I don't want a built up finish nor one that looks as glossy as a pimp-mobile, but I also want to get the project done. Will the surface of the wood eventually become saturated and the finish stop turning dull or is this as good as it gets? What am I missing here as the dull sheen is a bit too dull for my taste and it just doesn't look any good? Should I top coat with something that will give a more satin look? Other than this problem pure tung oil is pretty cool stuff. Thanks much for any help.

You need to do a rottenstone finish after you get done with the oil finish.

Thanks. After sticking to it I think my skim coats are working out. There doesn't seem to be nearly as much oil soaking into the stock and the level of finish is still pretty low to the surface. The sheen is also turning into a nice satin. Since this is a milspec stock my goal wasn't to make a show piece, but rather something that fit within the context but at a grade a bit above average. I think I'll shoot for something a bit nicer on the next stock. I may be sold on tung oil.

Generally it's advised to fill the grain first. Spar varnish is suggested to get that done faster. Then sand to level the finish and then do your oil finish. And rottonstone (or whatever) to kill the glare. But I've done this myself only once or twice preferring other finishes.

I did sand with fine grain wet and dry paper, but with the tung oil and not spar varnish. I think I'm going to use your method on my next stock. Right now the grain is mostly filled, which is fine for what I'm trying to do. Thanks

And the "filled" grain will remain that way until the uncured oil down in the wood cures... oils shrink as they cure and those pores will telegraph very soon.

There is nothing tung oil does any better than linseed oil. "Boiled linseed oil" is simply low grade oil sold in hardware stores with lots of garbage added. Tung oil tends to be higher grade oil when purchased because none of it goes to "food grade," because many people are allergic to tung.

The finishing industry substitutes each for the other and many tung oil finishes have absolutely no tung oil in them.

There are many different ways to fill wood pores but none are as bad as sanding slurry left in them. Please make a sample board sometime with several different finishes, including wet-sanded slurry. If you do not see the loss in depth and luster you need to get your script changed. Shellac makes a great sealer for woods that will not be used in bad weather. It sticks to everything and about everything sticks to shellac.

Because oils used to be very expensive and often very old, hand-rubbing was a reasonable application method. Today, it is far easier to apply oil rather heavily and quickly. Then let cure for 10-15 minutes before wiping completely dry. Lots of coats can be applied quickly and will build to a beautiful luster.

Guess I should clarify - the advice I've read (Newell and others) is not to wet sand but brush on varnish to fill grain with just resin. No filler. Somewhere along the line I read it's ok to wet sand after the first coat as the "dust" is just resin. Thought is the fillers make the finish look muddy. Does to me. Never hurts to do a practice piece and make up your own mind on what works and looks good to you.

Yup...

Sitka knows.

Never had much luck with the heavy coat and wipe method. But that's me, don't have the technique right I'm sure. Why you make practice pieces.

Yes, I got that. I should have been clearer. I wet sanded the tung oil to create a grain filling "dough" from the oil and bits of saw dust. And yes I intend to use spar varnish and sand when dry on my next stock. I do believe both techniques have been used to success. Thanks again.

If you ever have problems with the "Apply Heavy, Wait, then Wipe" routine there are only two sources of issues, your oil or your rag. If your rag drags while wiping, you waited too long. If pieces of your rag end up in your finish you need a different fabric, old bedsheets work well. If it takes too long to build wait a little longer before rubbing dry, or learn to be more patient.

Old time gunsmiths got away with sanding slurry filling because they usually used much better wood with very fine pores.

That dough you speak of is what degrades a quality finish...

I like the procedure of first coat being cut with mineral spirits 1/1 allowing the mixture to soak in deeper. 2nd coat 2/1 and wipe dry after an hour or so. 3rd coat straight tung oil applied in thin coat. Wipe dry. 4th-6th coats usually 24 hours curing, wet sand very lightly with 800 grit. Finish coat. Wipe daily for a couple of days to remove any residue or bleeding of finish. Let cure for a week or more and finish with Johnson's paste wax. Week later with a coat of Renaissance wax.

Didn't know that. Thanks again

Sounds good. Thank you

Please make a sample board with your finish on one side and and the same finish on the opposite side but leave out the mineral spirits. Then cut the board in half, wait a day and look at the difference in penetration. Solvents improving penetration is a myth. And they create issues in other ways.

So you recommend not cutting tung oil with mineral spirits?

That is correct. Solvents seem to make finishes thinner, but the basic molecules are still the same size and the solvents simply run away from the finish... basically the wood acts like a filter. The reason for waiting a day after cutting the sample board is the wood is often still wet with the solvent and the finish looks to have penetrated more deeply. It doesn't.

Interesting. I never thought of it like that.

Sample boards will show you all kinds of things...

Jeff, you were well advised to use pure tung oil on your project. While tung oil and "boiled" linseed oil are totally interchangeable, it is so only when good linseed oil is used. To even the odds of getting good stuff I make a bee-line to the local art supply store. An added benefit of using their stuff is that they sell oil in small bottles with attendant lessened risk (guarantee) of it going bad before the project is completed or the next project is started.

As for filling pores, I learned loooong ago that filling with sanding slurry is a waste of time and energy for all the reasons Art outlined not to mention durability. But, we are all missing Jeff's point- he's going for a 1920'-1930's vintage Springfield Amory oil finish on his stock. Those folks back then didn't give a horse's patoot about filling pores in that black walnut they used. They used linseed oil and tung oil interchangeably in the process- whichever the procurement officer could get the best deal on at the moment. Into the vat of warm oil the stocks went, waited a few minutes, out they came and wiped down and then the next batch came through. (This I got from an old friend who witnessed it at Springfield when he was in training to be an Army ordinance field artificer early in WWII.)

Were it me when your project is done, I would wax that bare wood (which is essentially what you have after wiping oil on and off- it looks good but with no real protectiveness) with a good paste wax for a bit of protection. Remember the military with their oil finish didn't care that it wasn't the very best wood finish- it was cheap and quick. The Army didn't care that stocks would suffer as a result. Uncle Sam had deep pockets and would just buy you a new one if needs be.

One after-finish treatment that my old ordinance artificer friend showed me was the wax/rejuvenator/waterproofer they were taught to mix and issue the guys in the field for use on their stocks. It consisted of beeswax and oil (take your pick) melted and mixed to give the consistency of shoe polish, with turpentine to adjust the viscosity. Rub on, buff off. It's what I have used for decades to spiff up Springfield stocks. (I like the smell of turpentine, but if you don't just substitute mineral spirits.) Note: be careful when melting the beeswax. Do it in a double boiler or you might have an epic fire emergency.

Another point about stocks of the era which I also failed to mention was boning. Just rubbing the stock carefully and firmly with a piece of bone.

Gary - thanks. I checked my last application this morning and I think I like how its turning out. My last thee applications have been thin skim coats that were rubbed in with my hands. I used no cloth. And by skim I mean that I barely got my hands oily with just enough finish to bring a shine to the wood (like you would get if you wiped it down with water) before I set it aside to dry. Personally, I like the smell of tung oil. My goal was to get a finish that looks like what you see on some of the more better finished rifles from the US arsenals and I think I did it. With a standard issue 03 or 1917 I would have been happy with just getting oil into the wood and calling it a day. But for this one I was shooting for what you would see on a NM or NRA Sporter. That is, something that was just a cut above standard issue and with the M2 I was happy with the grain not being fully filled. My next projects are the NRA Sporter I told you about, a Savage Super Sporter in 250-3000, and a standard issue Remington 1917. This project was a trial run for those as its been a few years since my last stock refinishing projects.

So, for a more historical method of finishing gun stocks, here's what I learned:

1. Use tung oil or a high quality linseed oil from a art supply shop
2 Use spar varnish to fill the grain and don't bother with the "sand to make dough method" for any quality of finish above military grade
3. Don't cut the oil, but put it on full strength from the start
4. Apply the final coats very (and I mean very) thin until they no longer "suck" into the surface of the wood
4. Allow plenty of time for drying between coats (a good reason to have multiple projects in the works)
5. Top off the final product with a good paste wax or for a military grade finish use the beeswax/turpentine concoction mixed to a consistency of shoe polish
6. Be patient and have a snort of good whiskey between each step

This leaves me with one more question about paste waxes. Based on auto projects in the past I learned to stay away from any product that contains silicone as it plays hell with the surface should you ever need to repaint the car. Is there a similar issue with gun stocks?

I appreciate all of your advice and I'll have a snort for each of you. This is a great forum with participants like you guys!

Does this increase or knock down the sheen?

Silicone will contaminate any finish, you'll wind up with a bad case of fish-eye.

Thinning the initial coats with mineral spirits WILL be absorbed a little deeper (wood cell structure does that by capillary action) and has the added benefit of drying the application a bit faster to allow subsequent coats sooner.

Actual testing over many years with many different finishes shows both assumptions to be wrong. The mineral spirits outruns the finish and goes deeper, but the finish does not. In most cases it reduces the finish penetration. It also slows curing of oil finishes rather than speeding them up.

Also, in some non-oil finishes, like epoxies, mineral spirits and acetone will create pores through the finish as the solvents leave, greatly reducing waterproofing.

To test drying speed make two sample cubes and weigh them on a powder scale. Finish them two different ways and monitor their weights... very quick and easy test and then you can prove it for yourself. Penetration is easy to prove by the method I posted earlier.

Good oil with driers will cure very fast... several coats per day is usually possible.

And it will be very hard to eliminate without far more work than the original job.

It is hard to say as it depends on a lot of factors. Basically you are crushing the surface by burnishing.

when I use tung oil I use an applicator, then use my bare hand to rub, when it starts to getting warm, that's tells me its good, when I am satisfied with however many coats I want, I finish with bee's wax or Johnson paste wax.

I suspected this as silicone additives always caused problems with auto body work.

Sitka deer...

Alaska is Alaska so keep doing what works for YOU.

Hey guys, it's all good. We all have our own ways and techniques for doing things. Take me for instance. I had been doing the dumb approach for years until you guys set me straight. My thanks to all. I appreciate it!

Physics remains constant in all 50 states... lab tests back up everything I have posted here and I gave very simple ways to test those tests. In no way did I attack you or your posts beyond pointing out the fact you have fallen for very commonly held myths.

How about you take the few minutes required to show you are correct? If my comments are proven wrong, please call me on it. Nothing personal intended in any way. But I will tell you I have done the tests many times under very controlled conditions and helped many folks from here repeat them for themselves. Not one test has been anything but proof my comments are correct. I apologize in advance for not guessing about applying finish.

No, things work differently in Alaska, radiation from the aurora don't ya know.
Do your research. Sitka is in the mainstream of the experts' writings.

Even if the laws of physics didn't apply in Alaska, would it not behoove the responsible finisher to follow protocols worked out and proven in a harsh environment, making his finished product universally adaptable? (Uh, I better not take my treasured go-to gun on that dream hunt. It was given an oil finish in Santa Fe and it might not withstand the weather swings on the Kenai.)

Got ya there! My tinfoil hat provides a radiation shield because I use a 3' brim!

Radiation an auroras? Meh. Ain't nothing compared to the humidity and heat of a summer on the Chesapeake Bay. That stuff will shrivel your gonads quicker than any wimpy-assed radiation! For that you need hog grease and a Mexican sombrero.

There is saltwater just a block from my front door... But the stifling heat remains well below triple digits. I did turn on the AC a couple days ago at 61F.

Having once called "The Land of Enchantment" home, I can say the state can get high and dry, and in the winter at altitude, cold. It's a great state and if I could have made a living in my chosen career I would have stayed there.

Nope, nothing to do with "physics"...Alaska is Alaska is like California is California...state of mind of the denizens of different kinds of Wilderness.

???

Channeling Gus?

gnoahhh, I read an article by a respected finisher in I think it was a Rifle reprint where he discovered a technique that gave him the finish he always wanted and in a shore time. He shared the technique with another respected finisher who couldn't get even acceptable (to him) results. Told me some good methods may work for one guy but not another. Practice boards, find the technique that works for you if you want more than an average finish.

Lived in Alexandria/Arlington but worth it for the oysters and crabs.

There are lousy teachers and lousy students...

And sometimes they cross paths.

There is no reason for incantations, lip sets, oblique lighting, or secret codes...

Some of you mean to turn this into alchemy...

If a method works, it always works or it’s a different method.

Yeah, next old rifle I buy, am making sure I get another with the same stock so that I can saw it in half after using it as a "practice board".

How I'd say it. Like me and the slop on - wipe off method. Like Sitka pointed out (thanks) I'm using the same method but probably out of habit doing something wrong with the way I'm doing it.

??? You don't have scraps of walnut where you live? Doing a test board is, like, Finishing 101.

Menard's etc. sells pieces of plain walnut cheap enough. Not the same but close enough I've found.

More like a prerequisite for High School Wood Shop back in the day...

Sad when someone was mislead and insists on passing bad info on. Even when good info, and an easy route to proving it, is available.

Well it seems like there's controversy regarding the ability of solvents to cause tung or linseed oils to penetrate deeper into wood. My two cents, which are worth a penny these days, is that the particles that make up tung or linseed oils are larger than those that constitute solvents - I may be wrong. But if so, the oil is only going to go down so deep into the wood - based on its density - and the solvent will go deeper - based on lesser density. Its kind of like how things migrate through soil (or how soil is formed) if you ever look at the sidewall profile of a trench. To me, solvents have always been a way to thin the materiel I use for the finish. So if the tung oil I am using is too thick and gooey I can make it work better by thinning it out with a solvent (being the son of a mechanic I have to say that solvents were usually good for cleaning up parts and jobs and not much else). I think artist use this idea when adding linseed oil to paint to make it flow better or to increase its working time before drying. Anyhow, that's my two cents worth which I'm sure has suffered considerably from the effects of inflation in the short time it took to write this post. Thanks again to everyone who kicked in on this post. I appreciate your help.

Bingo. I use solvents (usually naptha) to slightly thin top coats of varnish precisely for that reason- to make it flow better.

A very important point you made is about increasing working time of your finish... that is absolutely true. But because the solvent evaporates leaving less finish it is often confused with speeding the drying...

There is no magic; it cannot increase working time (pot life, open time, etc) without delaying curing.

Makes sense to me. Seems like you can have, say, 8-oz of tung oil in a cup to use on your stock. The 8-oz in the cup represents 100% of your finishing material and it is 100% tung. Now I can drain 4-oz out of that cup and add 4-oz of mineral spirits and still have the original 100% (quantity) of finishing material, but now 50% is solvent and only 50% is tung. And, as such, I would expect for that 50/50 solution to only be half as effective in accomplishing the job of finishing a gun stock because it contains less oil. Funny how its called thinner, eh? So now I have to ask if penetration actually decreases with the use of solvents as I would assume such solutions evaporate faster and transport less oil to he wood for every individual application. I also have to ask if it takes longer to get a stock job done for the same reasons. I guess I just came full circle with my dad and now see solvents as primarily good for cleaning up. Sorry for yammering on but I’m sitting here with a cup of coffee waiting on an oil change and as Paul Harvey used to say, “and now you know the rest of the story.”

Tell the oil change guys to thin the oil with some mineral spirits. It'll soak into the bearings better.

Will do and they’ll dig selling me a new engine too!

Laughing!

But BINGO!

Same mindset in Berkeley, Seattle, Portland, San Francisco. When are you guys having your parade?

Ah man. That wasn't called for. This is just a forum. When things make me pissed I just tell myself that all I'm reacting to are an ordered set of electrons on a computer screen that may, or may not, represent an actual human being. Its just talk and furthermore its just talk about ideas. Nobody has a gun to their heads. Its all cool.

Please, wake up and smell the solvent!

You have to know you are only guessing and continuing to dig when you are in a deep hole makes you look foolish and butthurt.

Okay, to throw a wrench in this- how do you think the new formulations of thinner ("Safe thinner, I wouldn't call them solvents) affect all of this? In my experience, the original formulations of solvents/thinners were pretty predictable in how they reacted with "Tung oil" and other oils, but the new formulations, courtesy of our friends in California, are just a pain to work with and in my experience pretty unpredictable in how they react with finishes. Now, try to find the "original formulation" thinners these days...

The other thing is, what lots of guys are calling Tung Oil may or may not be actual Tung oil unless you can determine it's chemical content from the label, if the manufacturer is generous enough to supply one. Most of the cans marked Tung oil these days are filled with a synthetic material that is definitely not plant or animal based. This can also cause difficulty with predicting how materials will react with solvents and other materials called thinners...

Bob

Good point, re: California-driven solvents. I don't know the answer. Like I said, I don't thin finishes except to thin spar varnish with naptha for top coating. The jugs of mineral spirits, acetone, and denatured alcohol I keep around are mainly employed as de-greasers and for mopping up epoxy squeeze out on glue joints and to de-oil oily woods such as teak and rosewood before gluing them.

You have been surprisingly civil. Kudos!

It's almost like you are trying to be less prickish!

Just admit that you don't understand the concept of a practice board.

Hey guys, I happen to be a "California-driven solvent" so be nice. Just kidding. The tung oil I'm using, the tung oil on which I based this thread, is identified on the label as "100% Natural Unprocessed Tung Oil." At least that'show the guys at Wood River bottled it the fine fellows at Wood Craft sold it to me. So I m assuming that I've been using the pure stuff with absolutely no added crap (geez, I wish our gas was that way). After going through the exercise of this thread I've become convinced that solvents are not necessary and that its just as well to use the pure stuff as, how they say, "straight with no chaser." And that includes both tung and, as Gary wisened me up to, refined linseed oil bought from an art supply shop and not BLO from a big box DIY center.

Sadly by some standards, but really no big deal at all... there is absolutely NO guarantee there is ANY tung oil in 100% tung oil bottles. It is no different from linseed oil in any significant respect and is legally bottled as "100% tung oil" if it is an oil that acts just like tung oil. Not long ago the label had to say "tung oil FINISH" in order to be marked as pure tung oil, but that appears to have been dropped fairly recently.

I would sure love to know how they managed to make the oil without processing it

And there are few other uses for thinners in finishes...

Back in the day when good oil was hard to come by a little thinner in oil made it easier to apply. But these days, thickened oil should be tossed.

CA did some ridiculous things based on a couple major advances they claimed could be duplicated... they were very wrong. Last I looked their limit on VOCs is 3% and that started about 5 years ago. Just shortly before that it had been 30%. The 30% goal had been reached by major advances and with nothing else on the horizon they demanded an order of magnitude reduction. They have placed a ridiculous burden on the industry and so far, they have failed to make anything resembling a user-friendly finish. I suspect there are a significant number of folks using non-CA finishes there simply because they have to to stay viable.

Sitka deer - where do you get tung oil? You can do a google search for what I have. It's distributed by Wind Rover and the label also says Filtered, No Fillers, No Additives and No Dryers. I got it from Wood Craft, which is a store that services wood workers. It is thick like honey. Wood Craft also has a catalog and I don't know if they have outlets in Alaska. If I can't get the real deal there then I don't know where I can. Thanks again.

Woodworkers supply houses on line is where I buy mine. You won't find it in your local hardware store. The stuff they sell is tung oil finish- actually a diluted wiping varnish full of dryers, resins, and god knows what else, not bad stuff in its own right but not what we're addressing here, intended for Happy Harry Homeowners and their weekend projects. And there's a good chance it doesn't even contain tung oil- linseed oil has virtually identical properties and is used interchangeably in the industry depending solely upon economics.

Brownells lists the Old Master's brand at $45/quart(!!). "specs: 100% pure, natural tung oil without additives or driers, for beautiful, hand-rubbed, in-the-wood finishes" Between Old Master's and Brownells reputations it's a brand to look for anyway. A quart is A LOT. Most of it has probably gone bad in the can and I didn't pay anything like $45 at the time. But it gave the finish I was looking for, pure or not. Bought a can of BLO at the same time, the tung oil came out a little less glossy on the test boards but otherwise the same.

I buy oil from an art store usually. I do not request tung oil, just oil. A very good local paint supplier sells it but their smallest container is bigger than I like. I like a 4 ounce bottle.

The last thing you want is pure oil with the consistency of honey. It should be very thin and runny.

I add a commercial drier.

You sure like hearing yourself talk...you a BPD, NPD, ASTD or combination of all of them? No one listening to you in the Anchorage tattoo shop?

Angle those walls some, you are getting deep enough to worry about a cave-in.

Unless they lied about no driers/additives (could be) IIRC correctly the tung oil hardened a little faster than the BLO which I'm assuming had a drier added. But not enough difference to make an impression. Also IIRC Newell in his book said that a drier wasn't necessary for tung oil and you can get crackling problems.

Next, how many angels can dance on the head of a pin I suppose. Test board whatever you come up with, also the little practice applying the stuff couldn't hurt.

Thanks

Interesting about the thickness. I recently picked up a bottle of refined linseed oil from an art store. Is this the same stuff you are talking about?

Yes, that is the right stuff.

Not correct, driers are required for natural oils to cure, without exception. Those driers can be produced naturally in the oil by heating, but that process kicks off the curing very quickly and to do that with a commercial oil would require inhibitors. Those are the things that take bad oil and make it virtually useless, as in BLO.

There are no physical differences between linseed and tung in use. Tung does not dry faster than linseed when applied in exactly the same way with the same driers. Without carefully sourced oils it is impossible to know what you actually have in the bottle.

Crackling problems are easily produced with any oils. Start by using heavy coats; do not allow them to dry completely between coats; and use different brands or formulas to guarantee the coats dry at different rates. That will cause some layers to shrink faster than others and it will produce a very interesting alligator pattern, that still feels extremely smooth. Only problem with it is after a significant period of time the finish will cure completely at all levels and the cool pattern will disappear. Years down the road the finish may start to fail if there are old-style resins mixed with the oil. That will cause actual alligatoring of the finish and there will be surface cracks.

I've been happy with the results from Hope's pure tung oil on my last two projects, which were english walnut and curly maple. Found the stuff on Amazon. I may try rubbing in some Birchwood Casey stock wax on one of my test pieces to see if it shines up just a bit. I've had this oil for at least two years now and it's still as thin as the day I bought it. I store it in one of those collapsible water/wine bladder bottles and squeeze all the air out.

Thanks. I'll have to check out "Hope's" brand of tung oil. The stuff I have been using is distributed by Wind River and it is thick. I previously described it as thick as honey but on second thought its more like pancake syrup.

Put it on your flapjacks. Perhaps thin it first so it digests better.

I will remember to do that! I'll have to add that its not as runny as that low calorie pancake syrup crap, but instead its more like high grade maple syrup.

With the delightful golden amber color?

Is there anything else?!

Comes right down to it, any more it is easier to skip the guessing game and I just go straight for Truoil. It seems they've all become some type of wiping varnish these days. Unless I want a clear finish, then I'll go for a good spray lacquer. As most finishers know, most of the finish is in the prep.

True, but I was intentionally going with the “old timey” approach to this project.

Truoil- solely a success because of Birchwood Casey's shrewd marketing in getting it on the rack in every gun shop in America. No more, no less.

While their marketing plan was brilliant, their product did not suck... TruOil is a viable finish at a relatively high price.

When I was a kid I knew a guy who had a tree trimming business and made gunstock blanks on the side. He, and others too, said that the beauty of Tureoil was that it allowed you to get a stock finished fast. After going "old school" with my M2 stock I now have a greater appreciation for what those guys said.

Sitka, Who said start with a small bottle, like 4 oz., of 50/50 spar varnish/drying oil and top it off with more oil after every application? Was that you? Pretty much Tru-Oil, no?

Yes, it is a common quick finish for me to use a new 4oz container of Spar Varnish and top it off with oil as I go... I never start with a 50/50 mix, but the end result is probably well over 50% oil. I slather the finish on and wait before wiping, so I use plenty.

TruOil is a proprietary blend and hard to know exactly what they use, but it has lots of the same resins commonly used in spar varnishes and very similar to the final total assay. However it gives the advantage (over TruOil) in giving resins in the base coat where it will do the most good and oils on the surface where it will produce the nicest finish.

Where I use TruOil over an epoxy base coat it works very well on myrtle... for some reason I have found the combination to work extremely well there. Pretty much to the exclusion of every other finish there. However, on walnuts I have found it is good, but I like other combinations, though I often (almost always) put a single coat of TruOil over epoxy and different oil finishes over that. I hate to admit I do not have a sound basis to justify it. But, I "feel" the TruOil makes a great binder coat between epoxy and oil. That is NOT based on any science or testing, but it makes me feel better doing it.

I have done many test boards with it and never really saw any difference or reason for it, but it makes me feel good...

Absolutely! And a new coat every few hours when the TruOil is fresh is very easy to do.

Thanks for the explanation. I have a second stock I'm prepping for finish. I have been tinking for some time about using spar varnish as a base coat and I now think i'll do it - though I may stick with tung or refined linseed oil as the top coat.

Somewhere buried in my boxes of crud I have a NRA publication from the late 50s/early 60s that talks about spar varnish and TruOil. And that was the golden era of DIY milspec sporter conversions so I suspect they had a big audience for publishing DIY gunsmithing articles.

Spar varnish builds awfully fast for true mil-spec finishing... TruOil does not build as fast, but does create a very glossy surface eventually. To improve the authentic look it does require a rub-out.

I think that's where I got the idea of starting with the 50/50 mix. Best I've been able to tell from a lot of reading Tru-Oil is a blend of spar varnish and drying oil, either BLO or tung (as if it really mattered) though no good hints on proportions.

Did a quick check and found a MSDS I don't remember seeing before:
Mineral spirits > 56% (by weight)
Modified oil < 33% (could be a cryptic way of saying varnish, or not)
Linseed oil < 11%

The next stock project is a Savage 40/45 stock from the 1930s. So I'll be shooting for something that looks appropriate for a commercial firearm from that period. I used to think it was more of an open grain finish, but after looking at a number of well preserved specimens from the period I pretty convinced the grain was filled. When refinishing stocks on older rifles I also try to make the finish on the wood match the condition of the metal, otherwise it ends up looking painfully obvious that the stock had be redone.

Didn't read all the advice but what I am doing is oiling then varnishing or sometimes a varnish shellac mix like Parker and other shot gun companies used. The fill coat is sanded back to almost bare wood. Then I go with what Art has advised an oil/spar varnish mix. I also add some Japan dryer or cobalt as these help the oils to dry from the inside. As you start to get a build up wait longer and longer each coat. I like James Howes method on "Modern Gunsmithing" of using a rotten stone & oil felt buffing wheel to apply the coats after the filler is done. This starts the buffing process and can take weeks off the finishing time. The wood is burnished in the process. It develops a fair amount of heat and you can actually burn the wood if you over do it.

A final couple of coats are Slacum which is oil, turpentine, Carnuba/Bees Wax, and some dryer. This is for the final buffing out and the Beeswax adds a soft luster better than anything else I have tried. The final slacum coat is not very durable for several years but is easy to re-apply. It eventually gets quite hard and the Carnuba speeds this up but doesn't buff out as satiny as the Beeswax. You can skip all this and just buff any modern finish and wax and then one final buffing for a similar result which is more durable.

Same here. I bought a bottle of Hope's pure tung oil off Amazon for an 870 stock and forearm. The shipping took for-friggen-ever, but it was worth the wait. Can vouch it is good stuff.