Gentlemen:
One of Zero Rust's real benefits is that it can be used on BOTH clean bare metal AND on less than a white metal blasted surface! We all know that the latter is the ideal, but more often than not it just ain't practical or possible to get there.
As long as you remove any loose or flaky rust (which entraps oxygen and therefore rust will likely continue) you can then apply ZR and be assured that maximum adhesion will result.
I would advocate use of our Prep-Step as an added precaution to making sure that the metal is free of greases and any other contaminants that will interfere with paint adhesion - regardless of what kind of paint you use.
HTH
WK Irish
