Two of the most common finishes on hardwood are wood oil and varnish. Both finishes offer glossy protection, but what’s the difference between them?
The main difference is that wood oil needs to penetrate the wood to stick, while varnish binds to the top layer of wood. That means varnish is glossier, dries harder, and protects the wood better.
Varnish lasts longer on wood, usually up to 10 years if properly maintained. Wood oil needs to be re-coated every two years or less.
Wood Oil
Wood oil refers to different types of penetrating oil finishes:
- Linseed oil
- Tung oil
- Teak oil
- Danish oil
- Mineral oil
- Walnut oil
Many of these oils are plant-based meaning that they are gotten from parts of different plants. For instance, linseed oil is obtained from Flax seeds, while Tung oil is obtained from the Chinese Tung tree. So, they are generally a natural wood finish.
Being a natural oil, it penetrates deeply into the wood. This allows it to protect the wood from within. Since it penetrates, it can’t crack or peel off like other finishes. But it fades faster and would need a recoat every two years or less.
You can use wood oil:
- To enhance wood stain and paint.
- To reveal the texture and grain of the wood.
- For moisture and wood protection.
- They are often used as undercoats for polyurethane.
- Natural oil finishes help to give antique look to wood.
Varnish
Varnish is a strong and durable sealant used to protect wood. There are different types, so the term “varnish” is a family name for all types of it.
The list includes spirit, polyurethane, exterior, acrylic varnish, and so on. Though there are different types, they all have very similar features. The binding feature of all types is that they are topical finishes. This means they don’t penetrate wood as deeply and stay on the top layer of the wood.
Since varnish doesn’t penetrate, the top coat is harder and stronger making it capable of protecting the wood. Varnish has a very glossy finish that repels moisture. Exterior varnish especially is very moisture-resistant.
You can use varnish:
- To protect wood from dents, pest damage, and water.
- To protect wood stains and paints.
- For a glossy finish.
- To deepen or brighten wood stain color.
Related Read: Can You Varnish over Wood Oils?
Wood Oil vs Varnish
To compare both wood finishes, we’ll use the features of a proper wood finish and see how both finishes compare.
Here is a table that shows the major differences between them:
| Wood Oil | Varnish | |
|---|---|---|
| Wood Protection | Good | Great |
| Gloss or Sheen | Good | Varnish offers a higher sheen |
| Dry Time | Takes at least 3 days to fully dry | Dries fully in less than 3 days |
| Purpose | Common on bare wood | Common on stained wood |
| Water Resistance | Good | Better |
| Durability | Poor (recoat every two years) | Great (lasts about 10 years) |
Now, let’s go into detail to learn more about these differences.
Wood Protection
Varnish protects wood better than wood oil because doesn’t penetrate wood as deeply. Since it doesn’t penetrate as much, there is more varnish on the top layer of the wood. This equals more protection against moisture, dents, scratches, and blemishes.
Since wood oil penetrates wood deeply, there is less on the top of the wood and more inside the wood. Since there isn’t much wood oil over the wood, the finish won’t protect the wood as good.
Moisture Resistance
Both finishes offer impressive moisture-resistance qualities. However, varnish remains water-resistant for years while wood oil begins to allow moisture to seep in after a year.
Since there isn’t much wood oil on the top of the wood, it will wear off due to friction and moisture.
Dry Time
Varnish dries faster than wood oil. That’s because it has dry additives in the formula and a thinner flow.
The thicker the finish, the longer it will take to dry. Since wood oil is thicker, it will take longer to dry.
Purpose and Use
Varnish is often used to cover stains and finishes on wood. This is because it doesn’t penetrate deeply so it wouldn’t be repelled by the stain underneath. Also, it is a clear film that will enhance the wood stain’s color.
Wood oil is used on bare wood rather than over finishes. This is because it needs to penetrate to stick properly, and if there’s paint or stian on the surface, the wood oil won’t be able to penetrate the wood.
Durability
Varnish lasts longer than wood oil because it contains driers and additives that reinforce the finish. Also, it doesn’t penetrate the surface as deeply, so there’s more over the topcoat that can last for years.
On the other hand, wood oil fades quickly, so you must touch up (re-apply) it every 2 years.
The Price Tag
Wood oil costs more than varnish because it is a natural oil that takes longer to extract. For instance, the Tung tree from which Tung oil is gotten is native to southern china, so you can expect it to be costlier than an average finish.
Indoor or Outdoor Use?
Varnish can be used indoors and outdoors, but the finish is more suited to exterior wood. Since it offers better wood protection, it will last longer on outdoor wood. Also, exterior and polyurethane varnish offer resistance against rainfall, heat, and UV rays.
Wood oil offers medium-level protection to the wood. This means it will protect the wood for a few years (or months) before getting washed off.
Cleaning and Maintenance
Varnish is easier to clean than wood oil. Varnish has a synthetic formula and as such can be easily cleaned with solvents. Also, its glossy sheen means it doesn’t absorb dirt or dust nibs. So you’ll be doing less cleaning and maintenance.
Wood oil is harder to maintain. Its natural formula means that solvents may discolor the finish.
Sheen Level
Wood oil has less sheen than varnish. Vanish due to the compounds in the finish has more sheen and is glossier.
Compatibility
Varnish and wool oils are compatible with each other. You can apply varnish over wood oil. Since they both have oil in the formula, they are compatible.
However, you can’t put wood oil over varnish. Varnish when dry forms a strong and thick layer over wood, its thick layer won’t let any liquid go underneath it. So, wood oil won’t be able to penetrate the wood because of the thick layer of varnish.
Which One Do You Need?
- Budget – You should purchase a finish that you can afford. Pure wood oil is often costlier than varnish due to the natural matter in the finish.
- Wood Protection – If you want better protection for your wooden surface, use varnish.
- Indoor or outdoor – For indoor surfaces, use wood oil as its better. For outdoor surfaces, use varnish.
Final Words
In summary, both are great finishes. The one you go for depends on your needs and the type of surface. Wood oil penetrates deeply so it should be used on bare wood. While varnish can stay on an existing finish so you can use it over paints or stains.
