What is the Difference Between Spar Varnish and Spar Urethane?

Spar varnish and spar urethane are both wood finishing products designed for outdoor use, but they have some differences in terms of durability, flexibility, and weather resistance. Here are the main differences between the two:

1. Ingredients: Spar varnish is a wood-finishing varnish that was originally developed for the coating of spars (long wooden poles that support the sails on boats). Spar urethane, on the other hand, is a type of spar varnish that consists of a polyurethane-based finish.
2. Durability: Spar urethane is harder, glossier, and more durable than spar varnish. It has excellent weather resistance and UV resistance, while spar varnish has comparatively lower resistance to weather and UV.
3. Flexibility: Spar urethane is more flexible than spar varnish due to its greater concentration of oil. This flexibility allows it to withstand the movement of wood caused by changes in humidity and temperature without chipping or cracking.
4. Finish: Spar varnish tends to chip, whereas spar urethane tends to remain a hard, shiny surface.

In summary, spar urethane is a more durable and flexible wood finishing product compared to spar varnish, making it a better choice for outdoor applications where the finish needs to withstand harsh weather conditions and UV exposure.

Comparative Table: Spar Varnish vs Spar Urethane

Spar varnish and spar urethane are both wood-finishing products designed for outdoor use, but they have different properties and compositions. Here is a table comparing the two:

Spar varnish is a wood-finishing varnish that was originally developed for coating spars (masts and rigging) and can withstand rough conditions. It allows objects to be flexed by wind loads, the effects of the sea, and bad weather. On the other hand, spar urethane is a type of spar varnish that has excellent weather resistance and UV resistance, making it more durable and less prone to chipping and yellowing.