I bought a gallon of the OSPHO product. It seems to work well but I am new to using these types of products. What happens to the bare metal that has been treated by using OSPHO or some other phosphoric acid product if you simply apply the acid and leave the metal alone (do not rinse, clean or prime/paint)? Does the acid wash process provide some long term/permanent coating to the metal, thus reducing the need to paint? Curious about applying the acid wash to metal in areas that will not be easily accessible to apply paint? Will the acid wash stop/convert the rust and then also leave some type of phosphate coating to protect the metal long term? Thanks!