Unfortunately, after spending forever carving out the hinges (mdf is not easy to do this) and finally hanging the door, I painted the edge to see that the primer was ok.  It felt overly smooth and we didn't know if paint would stick to it.  Well, it didn't.  So I sanded the door and did a new primer.  I tried 2 different paints and it scratches right off!  So frustrating and I am unable to use this door at this point.