My husband and I are in the process of repairing our tub. We had a few professionals tell us their process was to sandblast and then paint. We took it to a sandblaster ourselves and they sandblasted the outside only right to the metal. Do not let them do the inside because it will pit it. That was $45. We then took a belt sander (can purchase at Sears or possibly rent) and sanded it. This made it smoother for a better paint and it took approximately 1 hour. Very easy. It is now at a powder coating painting place. My brother makes wrought iron fences and uses this technique. It is a process that bakes the paint on. The formula is very durable and my brother uses it for all of his fencing. They will charge us $80 and it will be ready in one week. We had the outside painted white with black legs, but they can do several different combinations. Good luck!