Polyurethane and varnish are two popular finishes used to protect and enhance the appearance of wood. While they share some similarities, there are significant differences between them that can impact the outcome of your project. In this article, we will explore the differences between polyurethane and varnish and help you understand which finish is best suited for your woodworking needs.
What is Varnish finish?
Varnish is a type of wood finish that has been used for centuries. Traditionally, varnish was made by cooking a curing or semi-curing oil with a resin, such as fossilized pine sap. The oil used for varnish was usually linseed oil, but tung oil was also used later on. The resulting mixture would create a hard and protective coating on wood surfaces.
Today, most varnish available in the market is a combination of alkyd-resin, which is a synthetic resin made by polymerizing fatty acids and polyols. However, with advancements in technology, polyurethane has also been introduced as a popular varnish option. The latest varnish options in the market are polyurethane-modified alkyd varnish, which is a combination of alkyd varnish and polyurethane resin.
What is polyurethane finish?
Polyurethane is an ingredient used in the production of certain types of wood finishes and is not a standalone finish. Once it has dried, polyurethane forms a hard, plastic resin coating on the surface of the wood. There are two primary types of polyurethane finish
Oil-based polyurethane
Oil-based polyurethane finishes have been popular for many years and offer a number of advantages, including a warm amber tone that enhances the natural beauty of the wood, superior durability, and resistance to scratches and stains. However, they tend to dry slowly, have a strong odor, and can yellow over time.
Water-based polyurethane
Water-based polyurethane finishes, on the other hand, dry much faster and do not have a strong odor. They are also less likely to yellow over time, making them a good choice for light-colored woods. However, they may not provide the same level of durability as oil-based finishes and can raise the grain of the wood, requiring additional sanding.
Polyurethane vs varnish
The main difference between polyurethane and varnish is their composition. Polyurethane is a synthetic material made by combining a resin with a hardener, while varnish is a clear coating made from a combination of resins, oils, and solvents. This difference in composition affects their durability, application, and final appearance.
Is polyurethane and varnish the same thing: verdict
No, polyurethane and varnish are not the same thing. They are both types of clear coatings used to protect and enhance the appearance of woodwork, but they are made from different materials and have slightly different properties.
