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 between wood oil and varnish 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 than wood oil.
Wood oil penetrates wood deeply while varnish stays on the top of the wood. 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.
So, do you need wood oil or varnish? Let’s find out in this article.
What is Wood Oil?
Wood oil refers to different types of penetrating oil finishes.
Wood oils include:
- 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 part of different plants. For instance, linseed oil is obtained from Flax’s seeds, while Tung oil is obtained from the Chinese Tung tree. So wood oil is generally a natural wood finish.
Being a natural oil, wood oil penetrates deeply into the wood. This allows the wood oil to protect the wood from within. Since wood oil penetrates, it can’t crack or peel off like other finishes. But wood oil fades faster and would need a recoat every two years or less.
What is Wood Oil Used For?
- You can use wood oil to enhance wood stain and paint.
- Wood oil reveals the texture and grain of the wood.
- Wood oil offers moisture and wood protection.
- Dry wood oil finishes are often used as undercoats for polyurethane.
- Natural oil finishes help to give antique look to wood.
Now that we know what wood oil is, let’s check out what varnish is.
What is Varnish?
Varnish is a strong and durable sealant used to protect wood. There are different types of varnish, so the term “varnish” is a family name for all types of varnish.
The list includes spirit varnish, polyurethane varnish, exterior varnish, acrylic varnish, and so on. Though there are different types of varnishes, they all have very similar features.
The binding feature of all types of varnish is that they are topical finishes. This means varnish doesn’t penetrate wood as deeply as wood oils. Instead, varnish binds to the top layer of the wood.
Since varnish doesn’t penetrate, the top coat is harder and stronger making varnish capable of protecting the wood. Varnish has a very glossy finish that repels moisture. Exterior varnish especially is very moisture-resistant.
What Is Varnish Used For?
- Varnish protects wood from dents, pest damage and water.
- Varnish protects wood stain and paints.
- Varnish offers a glossy finish.
- Varnish can be used to deepen or brighten wood stain color.
Let’s now find out which wood finish is superior.
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 wood oil and varnish:
|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|
|Durability||Poor (recoat every two years)||Great (lasts about 10 years)|
Now, let’s go into detail to learn more about these differences.
Varnish protects wood better than wood oil. That’s because varnish doesn’t penetrate wood like wood oil does. Since the varnish doesn’t penetrate as much, there is more varnish on the top layer of the wood. More varnish on the wood equals more protection against moisture, dents, scratches, and blemishes.
Since wood oil penetrates wood deeply, there is less wood oil on the top of the wood and more wood oil inside the wood. Since there isn’t much wood oil over the wood, the wood oil won’t protect the wood as varnish does.
Both wood oil and varnish 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, the wood oil will wear off due to friction and moisture.
Verdict: Varnish offers better moisture resistance long term.
Varnish dries faster than wood oil. Dried additives in the varnish make the varnish coat evaporate and dry quicker.
Also, varnish is often thinner or lighter than wood oil. The thicker the finish, the longer it will take to dry. Since wood oil is thicker than varnish, it will take longer to dry.
Purpose and Use
Varnish is often used to cover stains and finishes on wood. This is because varnish doesn’t penetrate deeply so it wouldn’t be repelled by the stain underneath. Also, varnish is a clear film that will enhance the wood stain’s color.
Wood oil is used on bare wood rather than stains. This is because wood oil needs to penetrate to stick properly. If you put wood oil over wood stain, the stain will prevent the wood oil from penetrating deeply as it’s supposed to, and the wood oil will peel off. So wood oil is better on bare wood or unfinished wood.
Verdict: Varnish can be used over wood stain. But, wood oil should be used only for bare or unfinished wood.
Varnish lasts longer than wood oil. That’s because varnish contains driers and additives that reinforce the finish. Wood oil on the other hand has natural makeup with no solvent or additives.
Asides from this, varnish doesn’t penetrate as deeply as wood oil meaning that there is more varnish on the top of the wood to last for years. Wood oil will need to be reapplied every 2 years or less. This is because wood oil fades quickly. So you’ll need to touch up the wood oil.
The Price Tag
Varnish is cheaper than wood oil. Wood oil is costlier since it’s natural and takes longer to extract. Also, you can get varnish from a blend of other compounds so it’s not scarce.
The scarcity of the source of wood oil also makes it more expensive. For instance, the Tung tree from which Tung oil is gotten is native to southern china, so you can expect Tung oil to be costlier than your average varnish.
Indoor or Outdoor Use?
Varnish can be used indoors and outdoors, but the finish is more suited to exterior wood. Since varnish offers better wood protection, it will last longer on outdoor wood than wood oil. Also, exterior and polyurethane varnish offer resistance against rainfall, heat, and UV rays.
Wood oil can’t compete with varnish for exterior protection since wood oil has low weather resistance. However, you can use varnish for every type of indoor surface.
Verdict: Wood oil is better for indoor use. While varnish is better for outdoor wood.
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, the glossy sheen on the varnish means it doesn’t absorb dirt or dust nibs. So you’ll be doing less cleaning and maintenance.
Wood oil is harder to maintain. The natural formula of wood oil means that solvents may discolor the finish.
Wood oil has less sheen than varnish. Vanish due to the compounds in the finish has more sheen and is glossier than wood oil.
Varnish and wool oils are compatible with each other. You can apply varnish over wood oil. Since varnish and wood oils 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, the thick layer of varnish 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. You need to remove the varnish completely before you apply wood oil.
Do You Need Wood Oil or Varnish?
If you are still confused about if to buy varnish or wood oil, here is a guide showing important factors to consider. Hopefully, something here will make your decision easier.
The Price Tag
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. A pocket-friendly option is varnish.
Since varnish protects wood better, it will be ideal for floors and busy surfaces. Wood oil can be used to protect wood that wouldn’t be used heavily. Examples of such wood include photo frames, kitchen equipment, and the likes.
Indoor or Outdoor Use?
If you want a finish for indoor use, wood oil is better. Since wood oil is natural and pure, it is safer for indoor surfaces. The high level of additives in varnish means it’s not always the best option indoors but varnish will perform well outdoors.
Overall, varnish and wood oil are both great finishes. The one you go for depends on your needs and type of surface.
Wood oil penetrates deeply so it should be used on bare wood. While varnish can stay on an existing finish since it doesn’t penetrate as deeply as wood oil. Also, varnish offers better wood protection than wood oil. Wood oils are more suited to decorative tasks.