Although polyurethane and spar urethane are similar in some ways, they also differ in other ways.
So, what are the differences between spa urethane and polyurethane?
Spar Urethane
Spar urethane is a protective finish that is used for interior and exterior woods that may be exposed to different weather conditions. It protects wood from fading by blocking UV rays.
Polyurethane
Polyurethane is a finish that comes in both oil and water form. Water polyurethane cannot withstand high temperatures or heat.
Polyurethane is used to get a smooth and blemish-free texture on woods.
The following information will help you to better understand the difference between polyurethane and spar urethane:
Application
Polyurethane will require someone with advanced skills, as the wrong application may cause brush strokes or bubbles.
Polyurethane will also dry slowly; this will make the application process longer.
Spar urethane, on the other hand, is much easier to apply than polyurethane. Spar urethane will also dry faster as it doesn’t require many layers to get a shiny finish.
Features
The main difference between spar urethane and polyurethane is the amount of oil mixed with each of them.
Polyurethane is mixed with less oil and it is more hard and stiff. Spar urethane is mixed with more oil and is softer than polyurethane.
Pros of Each
Polyurethane is much more resistant to harsh conditions, and it will last longer and produce a quality finish.
Spar urethane generally has low levels of toxins and does not produce any odor or fumes.
Cons of Each
The main disadvantage of using polyurethane is that it emits an odor and strong fumes during application. These strong fumes may cause headache and dizziness for those who are exposed to it for lengthy periods.
When it comes to spar urethane, the well-known disadvantage is that it does not mix well with oil-based substances like paints. This results in color imbalance during application.
Conclusion
Both polyurethane and spar urethane are useful compounds that can be used to add a touch of protection (and quality) to furniture.
When choosing between the two, you have to consider the materials that you will apply the finish to, the conditions these materials will be subjected to, and your goals.
I hope this article helps. If you want to read about choosing a table saw that can cut your wood pieces to perfection, go here. Good luck!