I stained a box, and have yet to put a coat of polyurethane over it because i want to do an acrylic painting on the front of the box. Do I put the polyurethane first and then paint with acrylics, or can i paint the acrylic then use a top coat? I just don't want the acrylic to peel off over time if i don't put a top coat on it, but i also don't want to ruin my painting by using polyurethane if its bad for acrylics. What is the best way to do it?