Bumps in polyurethane

Michael White · 2005-03-17T04:39:20+00:00

Hi all,I'm trying to put a polyurethane coat onto a bookcase I'm building. Sinceit's a prototype, it's made out of cheap, soft pine. I've got it stained,and I'm trying to put on the final coat of polyurethane. But I keepgetting small bumps about 1 mm in diameter in the polyurethane coat. If Isand them down and put on another coat, they come back (although I'm notsure if they're in the same spot).This seems to occur no matter how thick or thin I put the polyurethane on. When I apply it, I've tried both not dragging the brush across the rim ofthe can and just knocking off the excess. I wipe down the surface aftersanding.I think I've got about five or six coats of varying thickness trying to getrid of these bumps. What the heck am I doing wrong?Thanks in advance.