The Difference Between Polyurethane and Spar Urethane

The Polyurethane and Spar Urethane Vanishes are the standard terms that are frequently used when it comes to having a perfect finish in your woodwork technology. Thus if you are an enthusiast in the DIY Projects, then this is one of the standard terms that any DIY Enthusiast is likely to come across. Spar Urethane is a common type of Urethane that is normally carried in water. On the other hand, the Polyurethane is a plastic resin that is also carried in water, and it typically meant for woodwork finishing. The two coats are often used interchangeably, but they usually have a big difference when it comes to their usage.

The two coatings are normally used in one or two pieces of furniture that we normally use or even come across. The two coatings have a very great difference, and one of the greatest differences is that the two Polyurethane has got a vast number of different compounds of Urethane despite the fact that we do have a significant number of differences between the two products. While on the other side the Spar Urethane is made up of many oil compounds which are cooked to form a varnish.

Spar Urethane Vs. Polyurethane

Spar Urethane

Spar Urethane is a common type of Urethane that is normally carried in water. It's one of the best varnish Products for outdoor purposes because it does not yellow as compared to other types of varnishes. Thus if you are doing an outdoor woodwork project, then this is one of the highly recommended Varnishes that you can consider. The fact that it's also water resistant makes it the best choice for finishing purposes on wood projects that are exposed to a lot of water.

When it comes to furniture that is usually moved often then this is not the best choice that you can consider. This is because the softness and pliability of urethane make its expansion and contraction very easy. Despite that, you can use the Spar Urethane with mineral spirits so as to form a thin layer which will reduce the effect of contraction and expansion of the wood.

Recommended Read: ​How To Apply Spar Urethane

                                                Can You Use Spar Urethane Over Paint


Polyurethane is a plastic resin that is also carried in water, and it normally meant for woodwork finishing. As the name sounds Poly- it made up of some Urethane which is joined through the Polymerization process. Polyurethane is usually non-toxic that is why they are commonly preferred in various woodwork purposes. They are the best varnishes that you can use for solid materials such as foot wears foams because they are very stiff and hard. They also provide a better coating that is shiny that giving your woodwork project a lustrous look. When you use this varnish, then your project is highly susceptible to dust because an ordinary polyurethane takes about 8 hours to dry. Despite that when you use the water base polyurethane then it's likely to dry very fast.

It's one of the best products since it's not only used for woodwork purposes, but it also bonds well with both the plastics and metals. It's also known to be very resistant to the harsh environmental conditions and oxidation levels. Its stability against the hydrocarbon solvents is also very high thus making it one of the best products that you can use.

Their resistance to wear is also high as compared to the Spar Urethane, despite that; they are commonly used for indoor furniture instead of outdoor furniture. When compared to the Spar Urethane then the Polyurethane have got a better compressive loading and also a better aging property. Thus for long lasting coating purposes, they are the highly recommended coating that you really ought to consider.

Usage Or Purpose

The polyurethane is commonly used for indoor wood furnishes because of the properties that they do have such as

  • Good aging properties.
  • Perfect Compressive loading.
  • High resistance to wear and tear.

On the other side, the Spar Urethane is best for Outdoor furnishing of the woodwork projects, and this is attributed to the properties that they do have such as;

  • High stability against hydrocarbons
  • High resistant to harsh environmental conditions and oxidation levels
  • They are stiff and hard.
  • High water resistant levels


Having a perfect and attractive is all that matters especially when you are a DIY Woodwork enthusiast. This is what will give you the motivation to work hard when you are dealing with your next project. That is why the choice of varnish that you will use plays a very critical role when it comes to having a perfect finish for your woodwork project. Also how you do apply the varnish also matters a lot, for instance when the Polyurethane is not applied in the perfect way the finished products might have some bubbles and brush strokes. This usually occurs when the solution is very thick. Such like imperfections might be avoided when you use the right brush and a very thin solution.

Related Posts:

The Difference Between Spar Varnish And Spar Urethane

Top 5 Best Spar Varnish Reviews 2017

How To Apply Spar Urethane

How To Remove Spar Varnish From Wood

Can You Use Spar Urethane Over Paint

Leave a comment:

Leave a comment:

Scroll Up