Nederlands | English | Deutsch | Türkçe

Project Sports

Questions and answers about sports

What does spar urethane mean?

4 min read

Asked by: Julia Schroeder

Whats the difference between polyurethane and spar urethane?

What is the Difference Between Spar urethane and Polyurethane. The difference between polyurethane and spar urethane is that Spar urethane is a more water-resistant finish. It can easily be applied in high humidity conditions, where polyurethane might fail if not given time to cure before the humidity rises.

Which is better spar varnish or spar urethane?

Spar varnish and spar urethane are two very different compounds. The main difference between the two is spar varnish will eventually chip or chalk off over time, while spar urethane will maintain a hard, shiny surface.

What is the benefit of spar urethane?

It is less susceptible to damage from UV rays and can prevent the wood from changing color. Spar urethane also offers slightly more flexibility so that the finish does not chip or crack as much when exposed to the changing temperatures, elements, or humidity levels.

Why do they call it spar urethane?

What is Spar Varnish? The term “spar varnish” comes from the boating world, where the long wooden poles that support the sails are known as spars. A spar varnish is a finish specifically designed withstand the rigorous conditions of seafaring life, which means it can also handle anything your backyard throws at it.

Should I use urethane or polyurethane?

In short, polyurethanes are far more durable and can be molded into a wider degree of applications than urethane, leading to harder, stronger and longer-lasting products depending on how many urethanes are added and what specific products a manufacturer desires.

Which is better oil based or water based spar urethane?

Oil-based polyurethanes tend to give a slight yellow color to the wood. Water-based polyurethanes are easier to clean up, but they’re slightly softer and don’t last quite as long as oil-based. Again the varnish needs to harden before applying a second coat. Water-based varnishes can be almost totally clear.

How many coats of spar urethane do I need?

Spar urethane is a type of clear wood finish that’s easy to apply, very durable, and protects outdoor furniture. It takes 3-5 coats of spar urethane to give your wooden furniture adequate protection. The more coats of spar urethane the better the protection from water, moisture, and the sun.

What is the best way to apply spar urethane?


  1. Apply a thin coat of Helmsman® Spar Urethane using a high- quality, natural bristle brush. …
  2. Let dry at least 4 hours, then sand entire surface lightly with very fine sandpaper (220 grit) to ensure an even finish and proper adhesion of additional coats.
  3. Apply second coat.

Can I use spar urethane over stain?

Greg Williams: Most stains, dye or pigment type, can be used under spar varnish. The most important caution with regard to a pigmented stain is to avoid applying too thick or heavy a coat of stain without properly wiping it off before brushing on the varnish, and to avoid over brushing the varnish.

Can you paint over spar urethane?

An acrylic latex paint is preferred because it is capable of forming a hard but flexible film over the relatively soft Helmsman spar urethane.

Is urethane same as varnish?

Unlike polyurethane, varnish is designed for outdoor projects and is not typically used for indoor surfaces such as a hardwood floor. While polyurethane is water- or oil-based plastic resin, varnish is older and made from resins, oils, and solvents.

Does water based spar urethane yellow?

About Ultimate Spar Urethane Water Based
Varathane® Ultimate Spar Urethane Water Based features a clear, non-yellowing finish that resists scratches and stays beautiful over time.

Why does spar urethane turn white?

You probably caused the problem by thinning the spar varnish. The wiping part was a good idea, you just used the wrong product. If you still have the cloudy finish, you will probably have to strip or sand it off—stripping being the safest(for the wood) choice.

Why did my spar urethane turn yellow?

According to Minwax, their Helmsman Spar Urethane may cause mild yellowing over light wood finishes, but their Water Based Helmsman Spar Urethane is supposed to be crystal clear and will not yellow. If used over some other type of light finish, the underlying finish may yellow slightly.