UPDATED 27Mar2020: Many people have trouble getting a nice smooth polyurethane finish on wood. I know because of all the questions I get on this topic. Click above to watch and learn about a very powerful technique for creating a glass-smooth polyurethane finish on any kind of wood. It works even when you’re starting with a not-so-great, brush-applied coating with bumps, bubbles and brush marks. I buy the pads you see in this video from Lee Valley Tools