I found this & thought you all might like to read it.

Tung oil has been used for centuries to waterproof all types of exterior woods. The ancient Chinese recognized the amazing qualities of Tung Oil. Throughout history, the Chinese have used Tung Oil to waterproof the masts and sails of junks and according to legend, to seal the Great Wall! During World War II, Tung Oil was used by the military in the Pacific to coat engine parts to prevent rusting . Tung Oil is resistant to many alkalis and acids as well. After its resistance to water, Tung Oil’s ability to remain flexible yet durable makes it perfect for exterior applications where the continual expansion and contraction of wood surfaces as they are exposed to moisture and drying heat stress the integrity of the coating. Moreover, unlike linseed oil, which darkens with age and exposure to UV light, Tung Oil’s light amber color is consistent throughout the life of the coating.

POLYMERIZATION AND FORMULATION

As Tung Oil dries and cures, the molecules join together in a tight complex formation. This process is the secret to Tung Oil’s effectiveness as a finish. The cross linking of the oil’s molecules makes the surface waterproof and impervious to many chemicals. The bonding also gives flexibility to the surface, making it capable of withstanding wear and tear.

Sutherland Welles Ltd.â uses a process called polymerization to intensify Tung Oil’s natural cross- bonding tendency. Polymerization is a cooking process that changes the molecular structure of the oil and further improves the natural cross-bonding reaction of raw Tung Oil.

Many other manufacturers of Polymerized Tung Oil will claim they polymerize their oil, but their "cook" is not as extensive as ours and requires formulation which includes additives such as varnishes and urethanes to improve the hardness, durability, and lustre of the finish. This adds to the toxicity of the finish and inhibits the penetration of the oil into the wood fibers.

The polymerization process used by Sutherland Welles Ltd.â is very sophisticated and "cooks" the pure, raw Tung Oil to its "maximum thermal threshold". Controlling the "cooking" and the "cooling" is an expensive process that at its perfect point produces an oil that has maximum durability and a gorgeous sheen. If the process isn’t well controlled the oil solidifies to the consistency of an erasure and the entire batch is lost. The intricacy and therefore expense of the process is what leads most companies to formulate with modifiers. They believe they can achieve the same results with a cheaper process and formulation. In time, the varnishes and urethanes discolor and deteriorate and with it the wood.

Thats good because I spend yesturday refinishing a book shelf with Tung oil. Tung oil really does
take a mediocre piece of wood and add a rich lustre...

Thanks for posting!

Regards,
Dave

Interesting read...thanks. Now I know just why folks say to stay away from Formby's, etc. Some years ago I was looking for pure tung oil and it took a bit of searching to find some.

I use Sutherland/Wells tung oil products and really like them allot. Their Tung Oil sealer is really nice stuff to use prior to starting the finishing process, and their Tung Oil Marine Spar Varnish makes a great finish for rifle stocks. Pricey...but really good stuff.

I don’t usually stain rifle stocks but I have done a small amount of testing and the Sutherland/Wells sealer works really well for getting stain mixed with it to penetrate deeply into the wood. The literature that comes with it states that this is one of the design features of the sealer.

Pure Tung oil, by itself, is not the best choice to use for finishing a rifle stock though.

I sent some Southerland/Wells sealer and spar varnish to Chic awhile back for him to try out and I would respect his opinion on how it compares with other products since he has far more experience in finishing stocks than I do.

In my experience, tung oil not optimal as a stock finish unless you're building a safe queen or else something that'll only see use in dry weather, and those versions with additives are also ineffective. There are so many more effective sythetic finishes available today that provide a pleasing "traditional" oil-looking finish that I don't see any reason go with tung oil.

I had a particularly bad experience with a tung oil finished stock on a custom 300 Win. Mag., which I used on a British Columbia goat hunt. One morning we rode to the based of a mountain that was known to hold some big billies, and half-way up it started to snow, and the flakes were big and wet. At the end of the day, back in camp, I looked the stock over, and all the finished was completely washed out of pores and the wood grain was pale and raised; it was a mess. Tung oil might have been used to preserve the Great Wall in the low-tech days, but in my case it wasn't even capable of keeping moisture out for one wet, snowy morning in B.C.........

One of my friends had a riflestock finished with tung oil that he's had to have refinished FOUR times now, and he hunts in all weather, from the Arizona desert to the Wrangells in Alaska.

I visited with a stockmaker who was all big on tung oil who stated that one of the virtues of that fihish is that it allows the wood to "breath". As I've found out, if it can "breath" it can also drown..........

AD

Allen,

If you are talking about straight, pure tung oil I would agree with you. Just the oil by itself is probably just slightly better than linseed oil as a finish.

The Marine Spar varnishes though are extremely resistant to moisture, in my experience with them, on rifle stocks, outdoor furniture and decks, and even wooden boats that sit in salt water 24/7/365.

I did a deck in my back yard with Marine Spar Varnish about three years ago and water still beads up on it.

Varnish is nothing more than paint without a color pigment added to it, so I’m not quite sure how a synthetic finish would be any different or more durable unless you are talking about maybe encapsulating the stock in liquid plastic or epoxy...and if that’s how one wants to go why not just get a synthetic stock and be done with it?

Back in ancient times when I still used wood stocked rifles and was making and finishing my own stocks, I used nothing but Tung Oil. I never ever had a problem.

The way I finished my stocks always included sealing the wood with a 50/50 mixture of spar varnish and benzene before applying the finish. I still have a some of those old stocks, one almost 50 years old. They've all been out in extreme weather and the stocks have never moved nor has the finish "washed off". It IS highly water resistant. The beauty of Tung is that a dab on your fingers at any time can restore the finish to "like new" when they suffer the usual scratches and dings from hard use.

One point about Tung Oil and the Chinese using it for waterproofing is how they applied it. The applied it on the underside and kept applying it till it soaked through to the top!
Most of our methods of applying it differ somewhat.
It is easy to repair, but wood probably needs to be sealed some other way before applying the tung oil as a top finish. Also don't forget to use a dryer with pure tung oil, it takes forever without it................DJ

You should try TEAK oil. Gives a very nice and durable finish