Spar Urethane Vs Polyurethane – What’s Better for My Project?

No matter how beautiful your woodworking creation is, you are aware that it could all be for nothing if the proper protective finish isn’t used.

Although this is usually a simple task, certain products strive to confuse users. One such instance is urethanes.It’s true that similar-sounding items can be used interchangeably. Although that is largely accurate, choosing between polyurethane and urethane spars can be a little challenging.

We’ll therefore outline their primary distinctions and when to apply each for the best outcomes.

You must take into account a few crucial variables when picking between polyurethane and spar urethane for your hardwood surfaces. Consider their resilience, simplicity of use, drying times, toxicity, ambering, adaptability, and weatherproofing. You can choose the one that is ideal for your project using these considerations.

Image	Product Name	Editor's Rating	Price
	Spar Urethane		Check Price
	Polyurethane		Check Price

What Distinguishes Spar Urethane from Polyurethane?

Spar urethane is more water-resistant than polyurethane, which is how they differ from one another. Where polyurethane could fail if not given enough time to cure before the humidity rises, it can be applied with ease in high humidity circumstances.

Yet compared to Spar Urethane Vs Polyurethane paint is more sensitive to solvents and alcohol. The finish of the wood may suffer if these chemicals are employed to clean the wood’s surface.

Contrarily, polyurethane is resistant to the majority of substances, including ethanol.

Spar Urethane: What is it?

A unique kind of varnish made specifically for boats is called spar urethane. Due to its use on the spar of sailing vessels, the earlier variant was known as spar varnish.

These goods are waterproof and effectively block UV rays, as you could expect. However, producers started including urethane plastic as part of the resins, which led to the development of spar urethane, making the product more appropriate for interior usage.

Thankfully, the urethane did not make it less UV and water resistant. The surfaces exposed to a lot of moisture and sunshine, as well as many indoor and exterior woodworking projects, can now be finished with spar urethane.

Spar urethane comes in two major varieties:

• urethane spar based on oil
• spar urethane with a water base

The tough finish spar urethane will shield your hardwood surfaces from dings, scratches, and chemical spills.

Both varieties of spar urethane perform the same functions, but oil-based spar urethane takes longer to dry, smells stronger, and has a propensity to become yellow over time.

Polyurethane: What is it?

A long-lasting, water-resistant finish with a very hard drying time is polyurethane. Although it may be applied to a variety of pieces of furniture, it is most frequently used on floors, tables, fences, and other surfaces that require water and scratch resistance.

Polyurethane is rarely used for high-end furniture because of how thick it may get.

There are two primary varieties of polyurethane:

• Polyurethane with an oil base
• Polyurethane with a water base

Despite the fact that they both do the same task, they each have particular benefits and drawbacks. For instance, oil-based polyurethane, which gives wood a warm glow, eventually becomes yellow.

Water-based polymer dries crystal clear and stays that way. When applied and maintained properly, both can be used to protect hardwood surfaces for more than ten years.

Benefits and Disadvantages of Spar Urethane

Pros

• Waterproof and scratch-resistant
• It is simple to use.
• It soon dries.
• It has UV shields.

Cons

• It doesn’t dry out all the way.
• Periodically, it needs to be reapplied.

Benefits and Disadvantages of Polyurethane

Pros

• Thick layer that is extremely durable
• Waterproof, chemical, and scratch resistant
• dries quickly and is durable enough to withstand heavy use.
• It can be used in a variety of ways.

Cons

• Drying takes a very long time.
• Emits significant amounts of VOCs

In-Depth Feature Comparison between Spar urethane vs Polyurethane

It’s time to pit these two items against one another and see who wins now that the formalities are out of the way.

But first, it’s vital to point out certain obvious discrepancies. Every widely available spar urethane product is suitable for both indoor and outdoor use. Best Little League Bats

Yet polyurethane is offered in interior and exterior varieties. As a result, polyurethane for interior and exterior uses has slightly varied qualities.

Hence, in order to keep things straightforward, we’ll concentrate more on how these goods are used inside.

Application Ease of Spar Urethane vs. Polyurethane

One of the first things you need to know when working with a new product is how simple it is to apply. Certainly, it might seem fantastic, but you are better off sticking with what you know if the process is complicated.

Several individuals claim that spar urethane is simpler to apply than polyurethane, yet this claim may not be entirely accurate.

These products require the exact same application technique: scuff the underlying surface, clean it, apply the first coat, let it dry, add the second coat, and repeat as necessary.

Some people favor spar urethane over polyurethane because the brush strokes are less obvious. This is accurate because spar urethane tends to level out better because it is a softer substance.

But only when applying polyurethane with an oil base is it true. Brush strokes and dust nibs are not as problematic with water-based polyurethane as they are with oil-based polyurethane. Moreover, polyurethane can be applied with a brush or a cloth!

This is a crucial distinction because more people are using water-based poly, even though it won’t affect the final grade.

Spar urethane won, although by a small margin.

Drying times for urethane versus polyurethane clear coat

Another popular subject that receives a lot of biased responses is this one. Most people who have used these two chemicals would, however, agree that spar urethane dries far more quickly than polyurethane.

That’s incredibly misleading once more.

It is well known that polyurethane dries far too slowly. Prior to applying the next coat, the first coat may need to dry for up to 24 hours. One coat per day? absurdity absolute! Nevertheless, spar urethane takes just 4 hours to dry enough for a second coat.

It would be tempting to call it quits on the comparison at that point because that is a preposterous margin.

But only if you’re talking about conventional polyurethane that is based on oil, not the quick-drying varieties. Oil-based, quick-drying polyurethane dries in about 4 to 6 hours, which is a significant improvement.

It is significant to note that some businesses only currently market their quickest-drying oil-based polys, therefore applying outdated criteria is pointless.

Both of the water-based variants of the products can be recoated in just two hours.

Oil-based spar urethane and fast-drying oil-based Polyurethane have the same curing times as their water-based counterparts.

The drying time is now significantly shorter when alternatives like one-coat poly and wipe-on poly are taken into account, making it somewhat quicker than spar urethane. Overall, the race is closer than anticipated.

Decision: a tie

Toxicology of Spar urethane vs. Polyurethane

Now we reach a choice where there is no chance of a victory. Nevertheless, the environment is not one of the numerous things or applications that polyurethane excels at.

Isocyanates and other substances that emit a lot of volatile organic compounds are present in polyurethane (VOCs).

Certain VOCs, like Benzene, are recognized carcinogens and can irritate the skin, lungs, and eyes when used.

As a result, using polyurethane, especially oil-based polyurethane, requires considerable caution. The one saving grace is that Polyurethane no longer poses a threat after drying.

Before you get the incorrect impression, I should point out that spar urethane releases a lot of VOCs as well, albeit not as much as polyurethane. Both the water-based and the oil-based versions are true in this regard.

There are a few water-based forms of spar urethane that release fewer volatile organic compounds (VOCs) than water-based spar urethane, although this is not widespread.

Spar urethane is typically more safer for both humans and the environment.

Conclusion: Spar urethane

Durability of polyurethane versus urethane finishes

Now, this is where the comparison gets very, really tricky (pun intended). Thankfully, Polyurethane makes that quite simple.

Polyurethane is one of the strongest topcoats for interior woodwork, as you are likely already aware. It dries extremely hard thanks to its special resin and solvent blend, and it will retain this firmness for years to come.

Both water-based and oil-based polyurethane share this characteristic. Some people still maintain that oil-based polyurethane is more durable, but such critics are still fixated on earlier, subpar iterations of water-based polyurethane.

While polyurethane dries as hard as possible, spar urethane does not. These products maintain some flexibility because they can be used both inside and outside.

This is because outdoor wood will expand and compress as the weather changes. The topcoat must therefore be able to accomplish the same without cracking or peeling.

Spar urethane doesn’t dry as hard as interior poly as a result. As a result, spar urethane is less resilient.

While polyurethane can last between one and two decades, spar urethane that is water-based or oil-based can last between five and three times as long.

Spare urethane is also more susceptible to deterioration that cannot be repaired long before that time.

Conclusion: Polyurethane

Ambering of polyurethane against urethane

It is important to include a product’s appeal when evaluating how long it will last. When we say this, we mean when the finish starts to bother your eyes and you desire a change.

Ambering is the main cause for which you would wish to alter the finish on the intact wood. Oil-based finishes have an amber color that gradually darkens with use. On dark wood, this might not be a problem, but on lighter wood or light paint colors, it might be an eyesore.

But, even if the woods are darker, you might not complain for the first few years, but ultimately it might irritate you. It is safe to say that ambering should likewise be regarded as a component of durability.

Oil-based polyurethane has no defense in this debate. It is clearly yellow, and as it ages, it becomes more so. The same is true for spar urethane with an oil base.

Let’s compare polyurethane and water-based spar urethane.

The water-based options are where we draw the distinction. Water-based poly is transparent till the end of time and will always be so. For water-based spar urethane, sadly, the same cannot be stated.

It technically is a crystal clear coat, however against light stains and woods, it ambers. So, you must first test it on a discrete area of the surface to verify it won’t turn yellow before using it in this manner.

Does polyurethane made with water yellow? Fair enough, certain low-quality water-based polyurethanes will yellow when they come into contact with white paint, and other products will yellow, but they often behave well when they come into contact with light-colored wood and stains.

Conclusion: Polyurethane won with ease.

Comparing polyurethane with helmsman-spar urethane for weather protection

Now, this is where spar urethanes excel and the comparison is maybe a little unfair. Spar urethane, which was initially developed for boats, is unmatched in its ability to withstand weather.

Spare urethane is resistant to water damage and UV radiation without causing the wood to turn gray.

However, spar urethane might seem milky when exposed to a lot of moisture since it has a slightly softer finish than polyurethane.

This can give you the impression that the finish is no longer functioning, but after it dries, it becomes apparent once again. Although polyurethane does not have this issue, it cannot withstand as much rain or sunlight.

UV blockers are often only included in external polyurethane. Interior versions fall far short of spar urethane in comparison.

Hence, spar urethane is preferable if you need to apply a top coat to inside wood that will be exposed to the sun all day.

Conclusion: Spar urethane

Versatility of Spar Urethane vs. Polyurethane

One of the many great things about polyurethane is how versatile it is. It can be used on any wooden surface because it is a very durable product.

Sadly, spar urethane does not work the same way. The main variation in how the two products are used is the flooring.

While polyurethane can be applied to wood floors, spar urethane cannot be used in the same way. Due of its relative softness, spar urethane will quickly lose its effectiveness in high-traffic areas.

It will be harmed by being repeatedly pounded by feet, objects, footwear, golf clubs, chairs falling, and anything else.

Polyurethane, on the other hand, dries hard and is tough enough to withstand any type of damage for years without degrading.

You might not want to use spar urethane on any surface you want to be rock hard, save from flooring. If you’re like me and like to put your feet up on coffee tables or tabletops, this might also apply to those surfaces.

Even while spar urethane is fantastic, the fact that some surfaces can’t utilize it is a little of a problem.

Conclusion: Polyurethane

Can Polyurethane Be Placed Over Spare Urethane?

No, polyurethane shouldn’t be applied over urethane spars. This is due to the fact that interior varnish or oil-based polyurethane have a lower oil ratio than spar urethane.

The old finish should be removed, and then the same finish that was previously applied should be applied. This will result in a quality finish for you without adding any extra work.

Can Spar Urethane Be Used Over Polyurethane?

Yes, you can apply spar urethane on top of polyurethane as long as it is completely dry. Spar urethanes are a little more difficult to apply, but they can be highly forgiving and stick to many different kinds of paint.

Before committing fully to your project, it is advised that you test the adhesion on a tiny, discrete area.

Judgment on Spar Urethane vs. Polyurethane

It’s seldom simple to compare excellent topcoats, especially when they serve diverse functions.

As a result, you must make a decision depending on your usage expectations.

When to use spar urethane

• The hardwood surface will be exposed to sunlight,
• You need some flexibility on the surface when there is a lot of moisture,
• Reducing toxicity is a top priority.

When to use polyurethane

• Focusing on regions with heavy traffic
• You want to keep a surface protected for a year,
• working with expansive surfaces,
• Developing bright colors