This Saturday I will rent a large sand blast set-up and blast 500 lb. of
steel ornamental fence and gate which will be set up outside. I stopped
by a NAPA auto store and bought "Rust Treatment, Destroys Rust". The
stuff is supposed to turn the surface metal black after two coats.
Should I use this stuff or should I just paint on a primer after sand
blasting, is this rust treatment step worth the effort?

After sand blasting I suspect there will be trace amounts of oil on the
fence from the air compressor. If I spray the gate and fence with an
airless sprayer with some paint thinner will that remove most of the
surface oil, there are too many cracks and crevices to wipe it by hand?

Will Rustoleum brand paint and primer sprayed from an airless sprayer
give good results, from this newsgroups it seems that the best paint for
exterior metal is an automotive type finish, though some people have
said they got good results from Rustoleum.

Thank you in advance for any help or suggestions.