I am getting ready to spray my car with Eastwood 2K epoxy primer then I plan to spray Eastwood 2k urethane high build primer and my question is on the prep of the epoxy primer for the application of the high build primer. Does the epoxy primer need to be sanded before applying the high build primer or is there a window of time that the epoxy primer can have the high build primer applied over it without sanding the epoxy primer first?