Oil finishes are commonly used on wood furniture and kitchen utensils. Generally speaking, oil finishes are eco-friendly, food-safe, and non-toxic. They're also easy to repair and produce a more textured grain pattern than many alternatives. They tend to be considered a more traditional finish, as oils have been used as wood finishes for thousands of years.
However, oil finishes generally don't offer the same level of protection and durability that you'd find with a lacquer or varnish.
Here are five of the most commonly used oil finishes:
1. Linseed Oil
Linseed oil, also known as flaxseed oil, is one of the most popular wood finishes in the world. Like other hand-rubbed oil finishes, linseed oil saturates deep into the wood grain to protect against scratches and changes in humidity. It is easy to care for, eco-friendly, and produces a satin finish that really brings out the color and grain of the wood underneath.
Raw, polymerized, and boiled linseed oil are all derived from the flaxseed plant, but have been processed differently and to varying degrees. Raw linseed oil is the purest form, but is sometimes impractical as a furniture finish due to the extended drying times- it can take several weeks for each coat of raw linseed oil to cure. Boiled linseed oil is common as a wood finish, but contains some potentially hazardous drying compounds. Polymerized linseed oil is the best of both worlds: pure and non-toxic with quick drying times.
2. Tung Oil
Tung oil is a plant-based oil used as a wood finish. It is clear, quick-drying, and penetrates the grain to enhance and protect the wood. It’s one of the oldest and most popular wood finishes in the world and is derived from the seeds of the tung tree in Eastern Asia. Tung oil has become a staple among fine furniture craftsmen in the United States and beyond. It is eco-friendly, non-toxic, and food-safe.
Tung oil is derived from pressing the seeds of the tung tree, which is native to Eastern Asia. The oil has been cultivated and used in China as a wood finish for at least 2,500 years.
Similarly to linseed oil, it is difficult to find furniture that is made with raw or 100% pure tung oil. Many craftsmen will use boiled or polymerized tung oil, and it’s also common for manufacturers to mislabel products as tung oil when they’re not. If you’re interested in a tung oil finish, it’s worth doing a bit of digging to understand exactly what finish is being used and what it’s comprised of. You can find pure tung oil from Real Milk Paint.
There are many reasons a craftsman might consider using tung oil to finish wood furniture. It’s all natural, non-toxic, and eco-friendly, and it doesn’t yellow as much over time as common finishes like linseed oil, nitrocellulose lacquer, or varnishes like polyurethane.
3. Mineral Oil
Mineral oil is a broadly used term to describe a clear, odorless oil. Most often, mineral oil refers to a derivative of petroleum. Despite this, mineral oil is generally seen as non-toxic and food safe. In fact, it's especially common on cutting boards, wood kitchen utensils, wood bowls, and any other wood products that frequently come into contact with food. It's also a common ingredient in baby oil, as it's been tested and approved for dermatological use.
Although mineral oil is non-toxic and food safe, it is not used often as a finish for wood furniture, as other oils on this list offer more desirable traits.
4. Walnut Oil
Walnut oil is derived from the nuts of the juglans regia tree, a relative of juglans nigra (which produces the black walnut wood used in our furniture). Walnut oil, like mineral oil, is often used on cutting boards and kitchen utensils due to it's food-safe properties. Raw walnut oil, like linseed oil and tung oil, possesses a fairly long drying time, so it's not uncommon for walnut oil to be cut with mineral spirits (boiling) or heated (polymerized) to speed up the time it takes for the oil to cure.
5. Danish Oil
Danish oil is a super common finish among woodworkers, although it isn't clearly defined. Similarly to mineral oil, the term danish oil can apply to many different substances. In fact, the ambiguity with danish oil is even more severe. The term "Danish Oil" is basically a catch all term for any oil-based wood finish.
Danish oil often contains tung oil or linseed oil along with several other ingredients– thickeners, thinners, drying agents, binding compounds, and more. Usually, danish oil finishes are a mixture of some type of varnish with either tung oil or linseed oil, but not always.
For example, Tried & True sells a polymerized linseed oil under the trade name of "Danish Oil."