I have an old steel metal bathtub. It was pink so shortly after I bought the house I used that tub painting kit, forget who makes it. Looked good for about three months then started wearing off, paint coming up and chipping. Been fighting it for a couple years now, touching it up. It looks hideous and I would've been better off leaving it pink. Is there something I can do to make this more permament, a certain type of paint or something?