Pure Tung Oil Finish

[George Octon]

Does anybody use this and like it and could you say a little bit about using it. And I am talking about the 100% pure tung oil.

How much do you thin it to apply? I would assume you would thin it quite a bit, 25 - 30%, maybe more? What is the drying time like? Is Japan drier recommended? Thank you. This will be for 4 teak chairs that set on a deck on a boat that get a fair amount of shade, but some sum too, maybe half and half.

I would think this would be much better than already made up oil varnish finishes like Minwax or Formby's.

[Scott Holmes]

Tung oil by itself is not a good finish. Tung oils true "claim to fame" is VARNISH that is made from tung oil (instead of linseed oil or soya oil) is more waterproof than other varnishes. Your best option is an exterior varnish made from tung oil. NOT any of the big box store POLYS; it doesn't matter if they say exterior or not they are inferior because poly is highly susceptible to UV damage; why put it in the sun? Some of the best exterior marine varnishes are found at boat supply houses, not big box stores or even paint stores. Epifanes is one of the best probably $60 per quart or more; you get what you pay for. Formby's (you don't get what you pay for here, 80% of the contents is mineral spirits which evaporates)Formby's is not even tung oil; it's an alkyd resin/soya oil varnish (highly thinned). Minwax tung oil finish is an oil varnish blend that will not do well outside.

[Howard Acheson]

Why do you want to use tung oil? What are you going to use it on?

Tung oil not a very durable or protective finish. Unless a high number of coats are applied, it is not very water or moisture resistant. It loses whatever moisture resistance it has in a period of time necessitating a re-application. It forms a very soft finish that is subject abrasion. It polymerizes (sort of dries) very slowly.

It's probably OK to use on some item that won't be handled and is kept in a protected spot.

[Steve Schoene]

I agree with Scott and Howard about the weakness of pure tung oil as a finish. And, in those rare occasions you do want to use it there is no point in thinning. Thinning won't increase penetration, that depends on the size of the tung oil molecule, thinner just spaces those molecules farther apart so you get less tung oil on a given application. The thinner just evaporates before the real penetration begins anyway. Remember too that in using any oil, or oil/varnish as a finish, the material should be vigorously wiped off the surface before it can cure. Tung does take a long time to cure--requiring several days between applications. If you go too fast, it can cause problems down the road. A month or more later it can turn frosty colored on the surface. Fixing that requires stripping and starting over. Tung oil is a bear of a material to use as a finish.

[Randy Goodhew]

Formby's is not even tung oil; it's an alkyd resin/soya oil varnish (highly thinned).

From a more reliable source:

Dear Randy,

Thank you for contacting Formby's. We appreciate your inquiry.

The Formby's Tung Oil Finish is a blend of Tung oil derived varnish and solvents. Like most Tung Oil Finishes on the market, it is not pure Tung oil. The use of varnish created from Tung oil allows our finish penetrate the wood fibers then form light protective film. This film helps protect the wood from abrasion, moisture damage and every day wear, while producing a hand rubbed appearance for your project.

I hope this information is useful. Please let me know if you have any other questions.

Sincerely,
Feraas
Formby's Product Support