Bubbles in polyurethane can be a major problem, leading to a weakened and less durable finish. There are a few key steps you can take to avoid bubbles in polyurethane, including using a clean brush or roller, applying thin coats, and allowing each coat to dry completely before applying the next. It is also important to avoid using too much thinner, as this can weaken the polyurethane and make it more prone to bubbling.
Avoiding bubbles in polyurethane is important for a number of reasons. First, bubbles can weaken the finish, making it more susceptible to damage. Second, bubbles can create an uneven surface, which can be unsightly. Third, bubbles can trap moisture, which can lead to the growth of mold and mildew.