Recently a neighbor recommended OSPHO, a product that bills itself as a primer for rusty metal. It chemically converts iron oxide (rust) to iron phosphate. This allows for any paint to better adhere to the OSPHO-treated rusty spots. It was pretty inexpensive and looked like a good approach. My tractor-restoring neighbor swears by it.
Does anyone have experience or opinions on this type of product? How does it compare to rust encapsulation? I welcome your responses.
