Tung Oil vs. Linseed Oil: Which Should You Use?
Woodworkers have been using oils for finishes for many centuries. And in most places, this is only because they are all they had and also because they would get finer finishes when they used them.
For the modern woodworkers, oils are still an essential part of finishing projects. Tung and linseed oils are the two most common types and if you do not have enough experience with both, you cannot always know what to use.
Each of the two oils is made up of different compounds and will be suitable for different finishes. Hence, they are ideal for different projects.
While having both tung oil and linseed oil in the workshop is a great idea, it is vital to know what each is all about plus its pros and cons so as to know what to use on your projects.
1. Tung Oil
Tung oil is a drying oil which means that it will dry by exposure to oxygen and not by evaporation. It is non-toxic and penetrating oil that is very useful for refinishing furniture.
Although tung oil will dry and penetrate into the wood slowly, you can quicken the drying time and also the time it takes to penetrate wood by adding turpentine or mineral spirits.
Tung oils come from the seeds of the tung tree. When you dry and press these seeds you get about 20% of tung oil.
This oil creates a clear and transparent coating on the workpiece which is great when you want to show the wood grain. But despite it being transparent, tung oil will tint the surface to a bit of a golden color. However, tung oil will not ‘yellow' or turn orange as much as linseed oil will as it ages.
Since it will not discolor over time, it will be a long time before you need to reapply it or use a different oil on the surface.
However, the fact that it is not scratch resistant might reduce its lifespan. If your project gets scratched it will be exposed as tung oil does not offer any scratch protection.
The coating that tung oil will produce is more water-resistant than what you get with linseed oil, and so it is suitable for use on outdoor projects and for things like bowls that will require regular washing.
Pure tung oil is also a food-safe product which also makes it ideal for application on cutting boards, plates, and bowls. Most linseed oils are not food safe.
Unlike linseed oil, tung oil is not prone to mold and this can be a significant advantage for projects that will be exposed to moist conditions often.
- More water-resistant. Tung oil is more water resistant than linseed oil and this is one of the factors that make it a popular finish oil. Also, the water-resistance makes it ideal for use on outdoor projects and for application on food-related items such as bowls and plates that will require regular washing.
- Elastic finish. Using tung oil to finish your projects will provide an elastic layer and this means that no cracking will occur as a result of the wood’s expansion and contraction due to the changes in temperature.
- Enhances wood’s sheen. The appearance of the workpiece is always vital and it is one of the key determinants of the correct oil to use. Tung oil will provide a semi-clear coating with a slight amber tint, unlike linseed which is more yellowish. This fantastic coating will help to enhance the wood’s sheen.
- Requires more coats. When using boiled linseed oil you will need just 2 or 3 coats to create a presentable finish, and you will only need to sand the piece smooth after the first coat. However, with tung oil, you will need up to 5 coats of the oil and you need to sand between the coats to remove roughness and this means more work.
- Slow drying time. Compared to boiled linseed oil, tung oil has a slow drying time. Since you need to apply more coats of it to get a presentable finish you should be ready to wait for 2 to 3 days for the tung oil to cure completely.
2. Linseed Oil
Linseed oil is another great natural finish and it comes from flax seeds. And just like tung oil, it is a drying oil that you apply in liquid form but it turns solid as it dries.
The finish that linseed oil produces falls between clear and a yellowish shade but it will turn into a more orange shade as it continues to age.
There are two common kinds of linseed oils which are raw and boiled linseed oil. The raw type is the kind that is fresh from the seeds and with no preservatives or additives and it takes a long time to cure. Sometimes it can remain sticky for weeks.
The other type which is also the most common for finishing among the two is the boiled linseed oil. And contrary to what its name suggests, this finishing oil is not boiled, but it instead has some solvents mixed in that make it act like it is boiled.
The addition of the solvents or metallic dryers to boiled linseed oil speeds up the curing and it takes about a day for it to cure.
And you will not have to apply a lot of coats of the boiled linseed to get the finish that you desire. Two to three coats with sanding after the first one should be enough to produce a presentable finish.
- More versatile. Besides from use as a top coat, linseed oil also has various other applications including in nutritional vitamins due to the high omega 3 content. Also, it is a common paint binder for oil paints. Tung oils, on the other hand, might produce a great finish but there are not many other ways of using them.
- Requires fewer coats. Unlike when using tung oil, you only need a couple of coats of linseed oil to get a good finish. And this not only speeds up the application process but also means that you will end up using less oil and hence saving some cash.
- Cures fast. Provided you do not apply it thickly and you wipe off any excesses, boiled linseed oil will cue much faster than tung oil. In most cases, a day or overnight in a warm room should be enough to cure the workpiece with the boiled linseed. With tung oil, you would have to wait anywhere between two and three days for the same piece to cure. But, also note that raw linseed takes longer than tung oil to cure, and it can remain sticky for more than a week.
- Not very durable. Unlike tung oil, linseed oil it will not harden adequately, and so it is not a highly durable finish. In some cases you still need wax to enhance its durability which means more work and cost for you.
- Not water-resistant. Linseed oil offers little to not water, chemical and heat resistance and so it will not be a good idea to use it on projects that will be exposed to these elements. Unlike tung oil, a surface with linseed oil tends to dull when it comes into contact with water.
Each seasoned woodworker seems to have oils that work well for most projects. While most will use both tung and linseed for different projects some only trust one of the two for all their projects.
If you have to pick one of the two common oils you should use your projects as a guide to make sure that you make the right choice.
When working for something for use outdoors or somewhere it will be at the mercy of the elements, tung oil is by far the best choice. Also, it is the best finish oil for food-related pieces that require regular washing as it is both food-safe and water-resistant.
Although linseed oil might not be as popular as it was in the past, it can still be handy for use with other types of finishes.
Also using boiled linseed oil takes less effort than tung oil. If you do not want to apply several coats of oil and wait for several days to get a presentable finish, boiled linseed oil is the better option.