If the surface of the metal is rusty but it also has old paint on it do you have to remove the old paint before using this product? I want to resurface a utility trailer I have.

RustSeal is best applied to bare metal where it can seep deep into the metal pores, interlock with it and cure watertight. If it is not possible to remove the old paint and it appears to be sticking well, you can apply RustSeal over it. You must first, however, wirebrush, etch or sand the old paint to create enough texture for RustSeal to bite into. Keep in mind that if that old paint should ever fail, RustSeal will peel off still attached to it.

If you choose to sandblast the trailer, RustSeal can be applied directly to the metal without any cleaning or additional prep.

If sandblasting is not an option, it would be best to remove as much of the paint as possible because the RustSeal works best as a rust preventative when applied directly to the treated metal. But, you can also remove the loose flaky paint and then clean the entire surface with KBS Klean and etch any areas down to bare metal with RustBlast before apply a minimum of 2 coats of RustSeal and then a topcoat (like BlackTop or KBS MAXX) because the trailer will be exposed to sunlight.

Please review the RustSeal Directions and let us know if you have any additional questions.