Oh goody one of my favorites...
Evaporust is just a product name on a Phosphoric acid based liquid. read the label and see what it's contents are.
Lookup "phosphoric acid and epoxy paint" and you'll find the answer is if the product (be it evaporust, Ospho,or PPG's own rust converter) to going to be painted with todays high quality epoxy primers IT MUST BE WASHED OFF WHILE STILL WET.
You can let it sit for days dried on and you're safe from rust but, when you're ready to prime first re-apply the 'whatever name it is' phosphoric acid and let it sit a few minutes. Then wash it off, I use an old scuff pad.
It doesn't matter that the product label says "apply, let dry, ready for paint". That's fine for rustoleum, it's a different type of paint (Acrylic) but for the price of even off brand products not to mention the TIME involved in the first let alone the second place I ask myself, "how can leaving an Acid under my paint against my bare metal even sound like a good idea?"
