Debunking Tung Oil Myths (canadianwoodworking.com)

At Halo, we often get requests for tung oil necks and we're always glad to oblige. We charge a little extra for it, as it takes more care and time... but if you love a fast neck and the feel of the actual wood on the back of the guitar's neck (as opposed to a poly clear coat), then a tung oiled neck might be for you!

I recently stumbled upon this article by Cynthia White and really enjoyed reading it, so I had to re-post some of the key points...

Wood Finishing: Take a closer look at this common finish; there are many things we can all learn about this ancient, and misunderstood, substance.

Myth #1

Tung Oil was invented by Homer Formsby in 1965 (Formsby’s Tung Oil Finish).

Nope. Tung oil has been around for thousands of years. There’s no doubt that Homer Formsby put tung oil on the map in North America in the late 1960s, when he started marketing his special finish. However, according to Bob Flexner in his book, “Flexner on Finishing”, Formsby’s concoction was really a wiping varnish made with (maybe) a little tung oil, a resin and a thinner.

The earliest reference I can find to the use of tung oil is in the writings of Confucius around 500 B.C. The Chinese have used tung oil, also known as China wood oil, for at least 2500 years for wood finishing, wood waterproofing, caulking, inks and paints. I also found some references to using tung oil for medicinal purposes in ancient history. I don’t suggest you ingest it or take a bath in it, but apparently some primitive cultures did. In the 13th century, Marco Polo wrote about the Chinese using tung oil to build and waterproof their traditional boats called “junks”.

Today, world tung oil production comes mostly from China (83 percent), then from Paraguay (about 14 percent), Argentina (2.75 percent), and Brazil (a tiny bit) and it is used in wood finishing, paints, inks, fuels and other things. According to Professor B. Sivasankar, who wrote a recent textbook on engineering chemistry, these drying oils form stable films that protect surfaces from corrosion and weather. This is why tung oil and linseed oil, for example, are essential components in paints. “Without these drying oils, paints cannot function as protective coatings.”

Myth #2

Tung Oil dries in the air by evaporation.

Nope. Tung oil definitely gets hard, but it doesn’t happen by evaporation. Chemists classify oils as “non-drying”, “semi-drying”, and “drying”. The word “drying” is misleading because the oils don’t really “dry” or evaporate; they “harden” or cure.

The most commonly known drying oils in woodworking are tung and linseed oil. They polymerize or solidify by a chemical process that requires oxygen (from the air) to create cross-linked compounds that make the oil get hard little by little, until it is completely hard all the way through.

Myth #3

BLO is just like tung oil, but better and cheaper.

Sorry, but that’s wrong too. Comparing BLO (boiled linseed oil) to (pure) tung oil is like comparing apples to oranges. So let’s look at both:

Linseed oil, which comes from flax seeds, has a long history.

Flax (cloth) fibres have been found from 30,000 years ago, and we know linseed oil was used in oil paints in Europe in the 14th century. Woodworkers have used linseed oil in wood finishes for a long time because it was readily available, flax being grown easily all over the world. Pure linseed oil dries more slowly than pure tung oil, but no one knows that because everyone buys BLO, which dries fast because of all the added chemicals! BLO is definitely cheaper, and it is good; but it’s not better.

Myth #4

Don’t use tung oil on food surfaces (like counters and cutting boards) because it’s risky for people with nut allergies.

Wrong. I heard this information stated adamantly and authoritatively several times in a few different places, but it’s just simply not true.

Myth #5

Tung Oil never dries and you can’t get a good result from it.

Yes it does, and yes you can.

So let’s recap: tung oil is more expensive than BLO, and it takes longer to dry. The chances of allergy to tung oil are remote, and tung oil has several other advantages over linseed oil. Professor Norm Kenkel, a biologist at the University of Manitoba, reminded me of another reason to use it: “Tung oil is an environmentally safe and sustainable wood finishing product.” There are reasons why tung oil has been used as a wood finish for thousands of years. It’s great stuff. For a traditional pure oil-rubbed finish, it’s the only game in town.