Rust mort ? or something else

[kcfirstbuild]

so I have a body guy working on my 68 cab. I'm just wondering what we should use once we get the paint off and we are down to metal. I dont want rust coming back so im looking for something I can spray on the metal to just make sure rust wont come back if we miss a small pit.

I have messed around with Sem's Rust-mort. Its worked good some small parts. Is this product something that can be used for prepping the metal prior to putting on an epoxy primer ?