Por 15, rust oleum, tractor implement paint, what to use on rusted metal

I'm using Eastwoods rust encapsulator on my duster project and my buddy is using it on his 63 f100 project... seems to be good stuff but I haven't given it the test of time yet .
I am trying to remove all rust either mechanically ,chemically ,and or electrically before using it so I feel pretty confident in the areas I do use it.