streaks in polyurethane finish on freshly stained farm table
I would go to a finer grit after the 220. Yes you need to sand until it is SMOOTH. Do you have a random orbit sander? Wipe on poly (50/50 poly and thinner) is a good way to go. The coats are thinner so you need 2 or3 more. Brushing works well but with a GOOD brush or a foam brush.