English Tudor completed in 1930.

Good sized heat feed and return pipes in basement and garage
need rust removal. I am using a cup shaped wire brush with
a drill. (That seems most efficient)

Ok, what paint or paints should be used with mostly bare
clean metal of these large heating pipes?
I think 1**a one-step rust fighter (like Benj-Moore Pro Spec
------- or Benj-Moore Ironclad)
2**and then a high tempurature radiator paint

There's a 1969 American Standard gas hot water boiler that
has no circulating pump. These pipes do sweat. I've learned that the water has to heat up to 180F or more to be able to circulate and have the radiators throw enough heat.

The pipes are "black pipe" with rust on some not all areas.
Assuming I get just about all the rust off, I'm not sure of what paint or combination will stop the rust from returning from the sweat and not flake off sooner due to the heat..

Thank you for your best info and/or advice
,

Brian Skinner