In the paint aisle, two of the most common types are polyurethane and polyacrylic. Both provide a harsh protective coat that can be used to apply on wood or metal, but they serve different purposes and have slightly different properties. It is essential to understand these differences when selecting the appropriate paint for a project, and this is what we will discuss in this article.
Polyurethane is water-soluble and works best on metal items like furniture or tools exposed to moisture over time. Polycrylic is an excellent choice for wood surfaces like decks or fences, especially if needed to withstand outdoor weather conditions such as rain.
Both originate from polymers. Polymers are compounds that form when chemical bonds connect many identical repeating units. In the case of paint, these repeating units form a durable plastic film covering the surface without being absorbed into its pores. The thickness of this layer determines the quality, longevity, and price of the paint.
Polyurethane is created by reacting a liquid polymer with a catalyst called a urethane prepolymer, which causes it to expand and form a sticky resin mixture. Application is by brushing, and when it dries, it creates a stronger plastic coating than the original wood or metal. It comes in two forms: an aerosol can or quart containers used with an HVLP spray gun.
Polycrylic, on the other hand, is solid at room temperature. It has higher moisture resistance and is more flexible than polyurethane. When painted onto a porous surface such as wood, the difference decreases peeling as it dries because fewer air pockets are beneath the finish.
When applying either product to a project, use a primer first to help prep the surface. It helps ensure that the paint adheres better and lasts longer. After the primer is okay, apply either product and paint in the same manner.
Despite its greater flexibility, polyacrylic is best for outdoor projects that will be subject to moisture. It is less expensive than polyurethane and is the best choice for homeowners who do not have a large budget. If not sure which to use, try both and see which one to prefer.