How Polyurethane Protects Wood
The use of polyurethane as a sealant helps to protect wood surfaces. The properties of polyurethane seal and coat the wood’s surface, protecting it from damage. This clear finish is required in any woodworking project to provide the final level of protection and beauty.
Applying a Polyurethane Finish
Polyurethane can be found as a paint or varnish finish. It can be obtained from any paint or hardware store and is often labeled as a wood finish. Polyurethane is applied directly to the wood surface using a bristle brush, which reduces streaking and provides an even application of the varnish to the wood.
Polyurethane and Ultraviolet Rays
Polyurethane should not be applied in direct sunlight or heat. The ultraviolet (U.V.) rays from sunlight and excessive heat breaks down polyurethane and weakens its protection. All finishes will succumb eventually to U.V. rays exposure in time but polyurethane may be more susceptible since it does reside on top of the wood surface.
Polyurethane does not penetrate the surface of the wood like other types of finishes. It dries on top of the wood and becomes a clear finish that provides an abrasion-resistant seal for the wood. It dries clear so the finish is a transparent and hard protective coat.