Do I have to use Mastercoat Metal Prep for my application/can I use another metal prep if yours is not available?

Metal prep is a very good step to take but not necessary in every application. It is highly recommended to use to dissolve surface rust, etch the surface, and ensure a toothy surface for adhesion for our permanent rust sealer. However the rust sealer will still adhere to surfaces that have been cleaned of oil and grease (use mineral spirits), and loose scale removed. If our metal prep is unavailable, other brands of metal prep can be used. We recommend phosphoric acid, preferably with zinc as an ingredient.