Ever eyed pine and pondered its potential with spar urethane? Dive in to uncover this pairing’s magic!
Spar urethane is one of the best finishes you can apply on most woods especially before keeping them outside since it can protect the wood from extreme weather conditions.
I have applied spar urethane on many pine furniture, wood carvings, floorings, fences, and many other indoor and outdoor projects.
Here I’ll discuss everything I know about using spar urethane on pine.
Let’s figure out, Can you use Spar urethane on Pine?
Yes, you can use spar urethane on pine. Spar urethane is easy to apply on pine and it makes a protective coat over pine to protect the wood from moisture, UV light, and weather elements. Spar urethane makes pinewood waterproof and enhances the pinewood appearance by improving the sheen.
But that’s a quick snapshot and there’s a lot more to know about using spar urethane on pine.
In this article, I’ll explore whether can you use spar urethane on pine and how to do that properly with step-by-step guidelines.
I’ll talk about the benefits of using spar urethane on pine with some tips and techniques which are useful for you.
Furthermore, I’ll answer some frequently asked questions as well.
Let’s jump in!
Is Spar Urethane Good For Pine?
Yes, spar urethane is good for pine since pine wood takes spar urethane so well and it easily makes a nice and smooth finish over pinewood.
Spar urethane saturates the pinewood fibers and makes them more flexible. The excess spar urethane will remain on the pine surface and start to make a protective coating over the wood.
This spar urethane protective coat will harden upon exposure to the outside air. Then polymerize and makes a super tough barrier that isolates and separates pinewood from the outside world.
Spar urethane coating works as a barrier to moisture. Outside moisture won’t penetrate the wood. Therefore, pine wood underneath won’t rot and is protected from moisture damage.
Plus, spar urethane contains UV blockers which are also known as UV adhesives. Those UV blockers of spar urethane protect pine wood from UV light.
UV light can crack or split the pine upon exposure, causing fading of pinewood and discoloration.
By applying spar urethane over pine, the wood underneath will be protected from UV light and direct sunlight and prevent discolorations and fading.
This is so much useful for outdoor furniture and woodwork.
Spar urethane protects pinewood from weather elements such as rain, snow, and extreme temperature levels.
Therefore, you can use pine furniture or woodwork, finished with spar urethane for any indoor or outdoor environment. It will last forever with little maintenance.
Spar urethane gives a nice and even-looking finish to pinewood which improves the wood sheen by highlighting the natural color of the wood grain.
Spar urethane comes in different variants of sheens including gloss, semi-gloss, and satin which represent the reflectivity of its finish.
Generally, spar urethane is thicker and harder than regular polyurethane finish. Therefore, you can do the finishing with less number of coats. But the drying time is much longer.
There’re mainly two types of spar urethane that can use on pine,
- Oil-based spar urethane
- Water-based spar urethane
Here’s how different oil-based spar urethane and water-based spar urethane will work on pine,
| Oil-Based Spar Urethane On Pine | Water-Based Spar Urethane On Pine |
| Affordable | Expensive |
| Give a slight amber/ yellow tone to the wood | Provide a natural clear finish |
| Less flexible | More flexible |
| Harder coat | Thinner coat |
| Susceptible to dents | Susceptible to scratches |
| Slightly darkens the wood | Won’t darken the wood |
| Takes more time to cure | Takes less time to cure |
| Thin with mineral spirits before the application | Thin with denatured alcohol before the application |
| Difficult to clean and mineral spirits are required | Easy to clean with water |
Both oil-based spar urethane and water-based spar urethane protect pine furniture and woodwork from environmental elements such as moisture, high humidity, UV light, cracks, and insect attacks.
They are just different from the functionality. At the end of the day, your pinewood will be totally protected with both oil-based and water-based spar urethane.
Spar urethane finishing coat over pine is more flexible than regular finishing coats. Therefore, pinewood can easily expand and contract according to the humidity changes of the environment without warping or cracking the wood.
Overall, spar urethane will increase the pine wood’s durability and enhance the wood’s appearance with extra sheen.
You can use spar urethane on pine with no issues. It will protect the wood from environmental elements and improves how the wood looks.
You won’t go wrong by applying spar urethane on pine.
What Can Spar Urethane Be Used On?
Spar urethane can use for any pinewood application. Here’re some common ones,
- Pine wood furniture
- Pine wood carvings
- Pine floorings
- Fences
- Patio Furniture
- Indoor and outdoor projects
- Cabinets
- Doors
- Window frames
As you can see, spar urethane can apply literally to any indoor and outdoor pinewood product.
To clarify things we discussed, let’s discuss some advantages of using spar urethane on pine.
Benefits Of Using Spar Urethane On Pine
- Spar urethane protects pine from UV light
- Spar urethane makes pine wood waterproof
- Makes a flexible finishing coat that prevents pine wood from warping
- Protects wood from extreme weather conditions such as rain, snow, temperature changes, high humidity levels
- Easy to apply
- Protect wood from cracks
- Avoid insect attacks
- Food safe when cured
- Spar urethane is non-toxic
- Improves the wood sheen
- Spar urethane increases the wood’s durability
- Makes tough and hard topcoat
Spar urethane is filled with lots of benefits. You can clear any doubts had with spar urethane. It is one of the best for pine to work under any condition.
Let’s head into the most interesting topic. The application part.
Tools And Materials To Apply Spar Urethane On Pine
- Spar urethane product (oil-based or water-based)
- Thinner (mineral spirits for oil-based spar urethane or denatured alcohol for water-based spar urethane)
- 120 grit sandpaper
- 320-grit or 400-grit sandpaper
- Lint-free tack cloth
- Clean rags
- Bristle brush or paint brush
- Mixing container (plastic or glass)
- Pine furniture or woodwork
- Pine scrap wood (optional)
- Face mask
- Latex gloves
Tip:
As you can see we have included scrap wood in the list.
This is because you can test the spar urethane fist on scrap wood before applying directly to your main pine wood project to see how spar urethane reacts with pine wood and to minimize application errors.
Gather the things up and get ready for the application process.
How To Use Spar Urethane On Pine?
- Surface preparation and cleaning
- Sand the pine wood surface
- Thin spar urethane with mineral spirits of denatured alcohol
- Apply the first coat of spar urethane
- Let the first coat dry properly
- Light sand the surface
- Apply more spar urethane coats
- Let the coats dry and cure
So, let’s discuss, each of the above steps in detail to get a wide and clear view of the application process of using spar urethane on pine.
1. Surface Preparation And Cleaning
First, you need to take your pine wood furniture or woodwork to a ventilated space because having good air circulation helps spar urethane coats to dry better.
Plus, finishing wood in a ventilated area is healthy because harsh chemicals and fumes that release upon finishing can cause skin and eye irritations.
Working in an area with good air circulation helps to remove those chemicals and fumes quickly from the working area causing no irritations or breathing issues. Weak mask and gloves for better protection.
Then, begin to clean the entire pine wood surface using clean rags to remove dust, debris, dirt, and grease.
Leaving dust and dirt on the surface can interrupt the functionalities of spar urethane on pine. Dust can trap inside the spar urethane finish and reduce its performance and ruin the wood’s appearance.
Wipe on the pinewood surface to remove dust and debris. You can remove stubborn dirt by cleaning the surface with TSP (Trisodium phosphate).
Saturate the clean rag with TSP and remove dirt and residues from the surface.
After cleaning the wood with TSP, let it dry completely.
Your surface needs to be super clean and nice before the application of spar urethane.
2. Sand The Pine Wood Surface
Sanding is essential before finishing any kind of wood to absorb and stick wood finish better to the surface.
Sand the entire pine wood surface with 120-grit sandpaper to eliminate dumps, surface randomness, and drips, and make it super nice and smooth.
Sanding opens the pores structure of pinewood which helps spar urethane to absorb well into the wood.
Sand evenly along the direction of the pine wood grain for even sanding without leaving sanding marks or scratches on the surface.
Sanding helps to even out the wood color and smoothen the wood for the greater good.
Sand the entire surface with even pressure without missing any spots.
Once you’re done with sanding, clean the entire surface with clean rags to remove sawdust and other residues.
Or you can use a proper dust collection pine system to collect the sawdust and make fertilizer upon them after drying.
Now your pine wood surface is super ready to take on spar urethane perfectly.
3. Thin Spar Urethane With Mineral Spirits Or Denatured Alcohol
Before applying spar urethane directly on the pine wood surface, you should thin it by mixing it with a thinner.
Even though thinning is an optional step, it is really important since spar urethane typically makes thick layers on wood which take too much time to dry. Sometimes even weeks.
By thinning, you’ll be able to apply thin coats of spar urethane on pine and able to get an even finish that dries and cures faster than un-thinned coats without forming blotches.
Thinning makes the application process lot easier and you’ll be able to get smooth, nice, and even finish quickly on pine with thin coats of spar urethane.
Thinning is easy. You just have to mix the spar urethane you selected with a solvent before the application.
Oil-based spar urethane can thin by mixing with mineral spirits. And water-based spar urethane can thin by mixing with denatured alcohol.
Minera spirits and denatured alcohol have high evaporation rate than spar urethane. By mixing those high evaporative chemicals with spar urethane the evaporation rate of spar urethane itself will also significantly improve.
This helps spar urethane to dry faster and more efficiently.
Here’s how to thin oil-based and water-based spar urethane before the application,
- Thin oil-based spar urethane by mixing four parts of spar urethane with one part of the mineral spirit in a mixing container
- Thin water-based spar urethane by mixing four parts of spar urethane with one part of denatured alcohol
Tip:
You can apply spar urethane on pine by wiping on, brushing, or spraying.
You don’t need to worry about thinning spar urethane when spraying because during spraying you can easily get a thin layer of finish. Not like the other two methods.
Thinning is good before wiping on or brushing methods.
Now your spar urethane is ready to apply on the pine wood surface.
4. Apply The First Coat Of Spar Urethane
Now apply the first coat of spar urethane over the pine wood surface along the direction of the wood grain without missing any spots.
Apply spar urethane on pine with even pressure to even out the wood color and to gain a nice looking, even finish without blotches and splotches.
You can apply spar urethane on pine by spraying, wiping on, or by brushing.
Apply thin coats of thinned spar urethane for about 10 to 15 minutes. but this can vary on the area you have to cover.
After the application, let the spar urethane absorb and settle on the surface for 30 minutes.
Then, wipe off the excess spar urethane on the surface with clean rags. Wiping off the excess is useful to get thin coats and to get an even finish that dries faster.
Once you apply the first coat of spar urethane on pine, you’ll notice it will quickly absorb into the surface. Spar urethane will saturate the pine wood fibers which makes them more flexible.
Being flexible is useful to avoid cracks and wood splits.
Once the wood fibers are saturated, the rest spar urethane will remain on the pine wood surface which contributes to making the protective topcoat.
You can first apply the spar urethane coat on scrap wood to identify how it will look and to minimize your application mistakes.
Tips:
- Do not shake the spar urethane container during the application process since air bubbles can trap inside the finish and they are hard to remove. Air bubbles can cause bumps on the spar urethane finish.
- Never use synthetic brushes to apply spar urethane since they contain a lot of air inside fibers which can release and trap the finished surface. Use a quality bristle brush to apply spar urethane on pine.
5. Let The First Coat Dry Properly
After applying the first spar urethane coat on pine wood, let it dry for 24 hours.
Generally, spar urethane takes longer time to dry than other finishes due to the high thickness of the coats.
This is why applying thin spar urethane coats is always recommended.
Drying time can vary on the environmental humidity and temperature changes. Sometimes it may take 12 hours or sometimes even days.
However, letting the existing spar urethane coat dry completely is your job before moving on to the next steps.
Because applying more spar urethane coats before the previous one dries completely can ruin the appearance and won’t give a good protective coat over the wood.
Keep the finished pinewood furniture or woodwork in a dust-free environment until spar urethane is fully dried, it is so difficult to remove dust once they are attached to the wet surface.
Upon drying, spar urethane starts hardening on pinewood and makes a protective coat to protect pine wood furniture or woodwork from weather elements such as moisture, UV light, water damage, and other elements.
Spar urethane improves the sheen of pine wood and gives a fresh appearance to your furniture.
If you’ve identified the missing spots upon drying, reapply spar urethane quickly for those areas. Most of the minimal mistakes can be fixed when applying extra coats.
Make sure to check the dryness of the surface before moving on to the next steps.
6. Light Sand The Surface
After applying the first coat of spar urethane on pine, let it dry and then lightly sand with 320 grit or finer sandpaper to smoothen the surface and to give adhesive properties to the coat.
Sanding the existing spar urethane coat helps the next coat to stick well onto the previous one because sanding builds good adhesion between the surfaces.
This is so useful since by light sanding you won’t see any layer separation once you apply the second or more coats over the existing spar urethane finish.
Light sand along the direction of the wood grain with even pressure covering the entire surface.
Once you’re done with sanding, clean the whole surface with clean rags to remove dust and other residues before applying the next spar urethane coat over the pine.
7. Apply More Spar Urethane Coats
Now apply the second coat of spar urethane over the first one along the direction of the wood grain with even pressure on the applicator.
Apply a thin coat of spar urethane to get a nice and even finish with no blotches, or tacky surfaces.
Likewise, apply 3 to 5 coats of spar urethane coats on pine to get promising results with a super protective coat.
Follow the same procedure when applying more spar urethane coats over pine. But you don’t need to sand the final coat of spar urethane since that’ll be the last one and you don’t need to make it adhesive for additional coats.
Apply a thin coat along the wood grain, let each sand for 24 hours, and then lightly sand before the next coat and then apply the next coat.
After 3 to 5 coats your pine wood furniture surface will be super protected from weather elements, moisture damage, and rotting and it waterproofs the wood perfectly.
You can see how spar urethane gradually improves the pinewood appearance with extra sheen.
8. Let The Coats Dry And Cure
After applying the final coat of spar urethane on the pinewood let it dry for 24 hours and cure for 2 to 3 days.
Yes, curing time is higher than drying time and it can even take days or even weeks due to air humidity and the weather of the area you live.
Upon curing spar urethane will reach its final status with a super hard protective coat over pine and improves wood appearance.
Spar urethane makes a hard tough coat over pine which protects the wood underneath from extreme weather conditions like snow, rain, high humidity levels, and temperature fluctuations.
Plus, it enhances the wood’s appearance by highlighting the pine wood grain.
Don’t use the spar urethane applied pine wood furniture or woodwork until it is fully dried and cured. Leave it a maximum of up to 5 to 7 days until fully cured.
That’s it, folks! Now you know the proper way of applying spar urethane on pine without making any mistakes.
Simple as that!
How Long Does Spar Urethane Last Outside?
Spar urethane last outside for about 2 to 3 years under extreme weather. With proper care and maintenance, you can keep spar urethane outside even over a decade.
Apply spar urethane on pine wood at least once per two years to keep the wood protected for so long and to keep it fresh.
After two years, the spar urethane coat tends to peel off from pine wood, which makes pine wood exposed to the outside world and the wood tends to discolor and color will fade away eventually.
Plus, wood will get damaged from moisture and UV light as well.
Therefore, clean the spar urethane applied pine wood regularly and restore the finish at least once per two years for the long run.
Reapplying spar urethane help to remove the amber/ yellowed tone that gives by oil-based spar urethane from wood and wood discolorations.
Once the seal is broken, spar urethane can last outside for around 5 years. Keep the container in a dust-free, dry environment to use for several applications.
Using proper storing techniques saves remaining spar urethane and your money.
What Is The Best Finish For Pine Wood?
Here’re some of the best finishes for pinewood,
- Tung oil
- Linseed oil
- Spar urethane
- Spar varnish
- Lacquer
- Shellac
Above finishes help pine wood to get protected from weather elements and they also improve the wood’s appearance a lot.
Spar Urethane Products To Use On Pine
- Helmsman Spar Urethane
- Water-Based Helsman Spar Urethane
- Behlen’s Rockhard Tabletop Spar Urethane
- BEHR Oil-Based Spr Urethane
- Ultimate Spar Urethane
- Olympic Spar Urethane
Above spar urethane products work well on pin wood. I personally recommend Helmsman Spar urethane since that’s the one I use most due to its high availability in my living area.
How To Protect Pine Wood For Outdoors?
You can protect pine wood outdoors by cleaning and finishing with a waterproofing sealer that contains UV blockers to protect pine wood from outdoor elements such as moisture, UV light, water damage, and temperature changes.
Apply spar urethane, spar varnish, lacquer, tung oil, or polyurethane over pine wood for outdoors. This is the best way to seal pinewood.
Those finished will make a protective coat over pine wood and enhance the wood’s appearance.
Clean the surface regularly and reapply before the existing coat fades away completely.
Use quality branded products to finish pine wood before keeping it outside. Follow proper application techniques as we discussed above to get a nice and even finish.
How Do You Weatherproof Pine Wood?
You can weatherproof pine wood by applying 3 to 5 coats of spar urethane, spar varnish, or polyurethane over pine wood and letting each one dry and cure completely.
Thin each coat with mineral spirits or denatured alcohol before the application.
Apply thin coats and let each coat dry for at least 24 hours and then lightly sand to build good adhesion between surfaces.
Once the protective coats are cured and hardened it makes the pine wood weatherproof and able to tolerate extreme weather conditions.
What Is the Best Exterior Oil For Pine Wood?
- Tung oil
- Linseed oil
- Danish oil
- Teak oil
Apply thin coats over pine and let each coat dry before applying another for the best results.
Let’s answer some frequently asked questions.
FAQs
Why should I consider using spar urethane on pine?
Pine is a softwood that can be prone to damage; spar urethane not only enhances its appearance but also provides an extra layer of protection against the elements.
How many coats of spar urethane should I apply on pine?
Typically, for maximum protection and a smooth finish, it’s recommended to apply 2-3 coats, allowing adequate drying time between each.
Can spar urethane change the color of pine wood?
While spar urethane is clear, it can slightly deepen the color of pine, giving it a richer, more enhanced look.
How long does it take for spar urethane to dry on pine?
Depending on the brand and environmental conditions, it generally takes 24 hours for each coat to dry thoroughly.
Is there a specific technique to apply spar urethane on pine?
For the best results, apply in thin, even strokes along the grain of the wood, using a good-quality brush or foam applicator.
Can spar urethane be used on both interior and exterior pine projects?
While spar urethane is especially known for exterior use due to its UV and water resistance, it can certainly be used for interior projects to offer a durable and glossy finish.
How do I prepare pine wood before applying spar urethane?
Ensure the pine surface is clean, dry, and sanded smooth, removing any dust or debris for optimal adherence of the urethane.
Does spar urethane have a strong odor?
Like many finishes, spar urethane has an initial odor when applied, but it dissipates as the finish dries.
How often should I reapply spar urethane to my pine furniture or structures?
For exterior items exposed to heavy wear or severe weather, consider reapplying every 1-2 years to maintain optimal protection and appearance.
Did I cover all you wanted to know about: Using Spar Urethane On Pine
In this article, I discussed, whether can you use spar urethane on pine and how to do that properly with the correct steps.
I have talked about the best finishes for pinewood with some tips and techniques.
Spar urethane can apply to pine with no issues. Apply 3 to 5 thin coats of spar urethane along the wood grain on the pine and let each coat dry for at least 24 hours before applying another. Lightly sand between each coat to get a nice and even finish on pine wood.
Furthermore, I’ve answered some frequently asked questions as well.
Hope you learned many new things about using spar urethane on pine without making any mistakes.
Try to apply spar urethane over your pinewood furniture to see promising results, especially for outdoor furniture.
