Can you stain wood after you put polyurethane on it?

if you have used a wax finishing agent on your subject piece, it might not be a good idea to use polyurethane over it. You probably should strip the wax coat as best as you can and then coat with poly. something tells me that since wax is an "organic base" material and urethane is synthetic, it might react with each other in a adverse way, or the poly won't adhere to the wood at all. Try contacting a builder's supply outfit and ask for specific information on this subject. Don't take a chance and ruin a good piece of wood. Good Luck!