Q: "Doesn't Water + Bare Steel = Rust
I know its not going to pit in the hour it might take you to go from prep to etch or epoxy, but it will form an oxide very quickly. Correct?? "
A: Great question! And you would expect me to say "Correct." But, remember what my father said, "When all else fails... read the instructions - TWICE!"
The key is clean hot water with a damp (not soaking wet) cloth. The cloth is damp enough to remove the residue but not leave the metal wet; the reason the water is hot is to promote immediate evaporation and prevent the reaction of steel and water!
In the time it takes to wipe down the residue (as previously described) then Prep, using a phosphate-based metal prep product, you would not encounter rust.