Tung oil and polyurethane are two finishes that protect wooden surfaces from moisture and water. But, what’s the difference between these two finishes?
Tung oil is a natural oil extracted from the Chinese Tung tree, while polyurethane is a synthetic finish gotten from several resins, urethane compounds, and solvents. To stick, Tung oil needs to penetrate a surface, while polyurethane doesn’t.
Tung oil takes longer to dry than polyurethane. On average, Tung oil fully dries within 3 days, while polyurethane dries within 48-72 hours.
Tung oil is a natural finish gotten from the extracts and seeds of the Chinese Tung tree. It’s an old and traditional finish used on wood surfaces such as furniture. It’s a penetrating film (coating) that soaks into the wood fibers to stick.
You must apply 5-7 coats of Tung oil for proper coverage, however, this prolongs its dry time. On average, Tung oil takes 3 days to fully dry while Raw Tung Oil takes weeks to dry. Once it dries, it forms a hard top layer that isn’t resistant to scratches or stains.
You must re-apply (touch-up) it every year because this wood oil isn’t durable and wears off fast. This means you shouldn’t use it for high-traffic surfaces.
You can use Tung oil:
- To get a glossy finish.
- To reveal the wood grain.
- Over wood décor and sculptures to reveal the details and carvings in the wood.
- To cover and protect the wood.
Polyurethane is a synthetic varnish made by combining solvents, resins, and urethane compounds. When dry, it forms a glossy clear coat resistant to water, moisture, and scratches.
Its main ingredient is urethane compounds. Urethane is a plastic-like substance that is flexible, moisture-resistant, and durable. Aside from urethane compounds, it also has several additives in its formula designed to reinforce the finish. This makes its finish durable.
There are two main types; oil-based and water-based polyurethane. The oil-based type is more common because it is stronger and more durable, and has better coverage. On the other hand, water-based polyurethane needs 4-5 coats, but the sealant is easier to apply.
You can use polyurethane:
- To seal stains and paints.
- To protect the wood from water and moisture.
- Over high-traffic surfaces.
- For outdoor surfaces.
- To protect floors from scratches.
- Over paints to make the finish moisture-resistant.
Polyurethane vs Tung Oil
To compare these two finishes, we will use the features of both finishes and see which finish is better.
Here is a table that shows the major differences between them:
|Color||Tung oil has an amber-like tone||Polyurethane is a clear coat so it doesn’t have any color|
|Application||Tung oil is applied with a cloth||Polyurethane is applied with a paintbrush or spray gun|
|Price Tag||Expensive||Cheaper than Tung oil|
|Moisture Resistance||Average||Very good|
Now, let’s check the differences in detail.
Tung oil adheres or sticks better to wood than polyurethane because it penetrates the wood pores to stick. When you apply it the wood oil soaks and binds to the wood grain.
Since Tung oil penetrates the wood pores and fibers, it’s harder to remove it from the wood. In most cases, removing it will damage the wood surface.
On the other hand, polyurethane binds (sticks) to the top layer of wood, meaning the sealant has a weaker adhesion to the wood.
Polyurethane protects wood better than Tung oil because it’s a hard and moisture-resistant sealant that protects wood from scratches, dents, and water.
Tung oil doesn’t protect wood as good because it doesn’t have a hard or rigid layer. Instead, its finish is prone to scratches, stains, and water rings. So, it’s not the best finish to protect wood.
Polyurethane will last longer than Tung oil because it has a more durable, harder, and stronger finish. On average, it will last up to 10 years (if properly maintained).
On the other hand, Tung oil won’t last more than 1 year and you must touch-up its finish every year because it wears off.
Polyurethane is a clear coat finish that doesn’t give any color to surfaces. Instead, it forms a transparent layer that reveals the color and texture of the surface underneath. This is because polyurethane doesn’t have paint pigments on its formula.
To get a color finish, you must mix it with flat or acrylic paint. The tinted polyurethane will have a colorful and durable finish. Also, oil-based polyurethane tends to yellow over time; this happens when you apply too many coats.
On the other hand, Tung oil has an amber-like or gold color. Its color is similar to the natural color of wood.
You can apply polyurethane with a spray gun, paintbrush, or roller. Polyurethane also comes in ready-to-use spray cans. So, applying it is easy.
To apply Tung oil you must use a rag as the wood oil must be wiped on the wood. For small surfaces, applying Tung oil is easier than polyurethane. However, for large surfaces, applying polyurethane is easier.
Generally, Tung oil costs more than polyurethane because making it is harder. The Tung tree, where Tung oil is gotten from, is only native to China. This makes it difficult to get the needed resources to make the wood oil. Also, the wood oil must go through processing to make it lighter since raw Tung oil takes forever to dry.
On the other hand, polyurethane is easier to manufacture.
Polyurethane offers better moisture resistance than Tung oil. The presence of urethane (plastic-like) compounds in the polyurethane formula makes it impossible for moisture (water or oil) to penetrate its coating. Also, the paint particles are tightly bonded, making it even more difficult for water to get through.
Tung oil is also moisture-resistant, but after a while, water rings and irregular lines will form over the finish due to moisture exposure.
Cleaning and Maintenance
Cleaning polyurethane is easier than cleaning Tung oil because the sealant doesn’t absorb stains or filth. So, you have less cleaning to do with polyurethane. Also, it has a slick finish, so you can wipe off the dirt and stains with a dampened rag.
Tung oil has a softer texture, meaning stains and filth will stick to it, so you must clean it more frequently. Also this wood oil doesn’t have good moisture resistance, so if you use a solvent to clean it you can remove it.
Which One Do You Need?
It’s difficult to choose between these two finishes, but here are a few factors to consider to make your decision easier:
- Budget – If you have a low budget, use polyurethane because it costs less.
- Moisture-resistance – If you need a finish with better moisture-resistant features, use polyurethane as it can protect a surface from constant moisture better. You can also wash and clean it more often, and the coating won’t wash off.
- The Application – Applying Tung oil is easier than applying polyurethane. You can apply it (for small surfaces) with a rag, while you must use a paintbrush or sprayer for polyurethane. However, you must re-apply (touch-up) Tung oil every year, while polyurethane can last up to 5 years without re-applying.
- Wood Protection – Polyurethane offers superior wood protection compared to Tung oil. When dry, it from a thick clear coat that protects wood from moisture, water, and scratches.
- Color – If you want to deepen the color of the wood, use Tung oil as it has an amber-like color that will enhance the wood grain color. On the other hand, polyurethane is a clear coat with no paint pigments, so the finish will be transparent.
Polyurethane and Tung oil are great choices as a wood finish. However, polyurethane lasts longer, protects the wood better, and is more durable. While, tung oil has an amber-like finish that reveals the wood grain and deepens the wood color, and it’s easier to apply.
Tung oil is suited for indoor surfaces, while polyurethane can be used indoors and outdoors.
Tony is a professional painter and an author of DIY Geeks. Tony has completed over 1,000 painting projects for his clients. It's safe to say he knows what he Is talking about,