A couple of months ago, Rick Mosher responded to a question about painting insides and undersides of a piece saying:
"The purpose of a finish is to limit moisture exposure of the wood to control the amount of seasonal movement and prevent checking as well as making it look awesome. So the last thing you want to do is have one surface more susceptible to moisture than the other. This will cause warping. Just wet one side of a board and you will see what I mean. So to make a long story short, you should strive for a balanced panel, finished the same on all sides."Does this apply to MDF as well? If so, if I prime the inside of a piece of MDF, must I apply a finish coat as well?