As winter approaches, it’s important to remember that all finishes dry slower in lower temperatures. Runs, sags and pressmarks are all more likely to occur.
To avoid runs and sags, watch the finish in a reflected light as you’re applying it. The reflection allows you to see if either of these problems is developing and you can brush them out to remove them. If you’re spraying you’ll also learn to spray thinner coats. If you’re brushing you’ll learn to brush the finish out thinner.
Pressmarks occur when something is pressed up against a finish that hasn’t fully hardened. The accompanying picture shows an example. The only thing you can do if you get a pressmark is sand out the damage (after the finish has hardened enough to sand) and apply more finish.
To prevent more pressmarking warm your finishing area or give the finish more time to harden, or both.