I recently painted a pipe with Platikote high temp paint for exhaust headers on cars. The can says to "cure" the paint at high temperature in an oven (non-household) at 600 for 5 hours or something like that or to just run the motor to cure it. I sandblasted the pipe to bare metal and painted it. I let it dry for about 5 hours (it was touch dry in 5-10 mins), wiped the dryfall off and put it on and rode for a couple hours. It looks like new and no paint has come off so far. The biggest thing with surface prep, in addition to sanding and removing any loose paint or rust scale, is to make SURE there is no oil of any kind on the surface. When you are doing the prep and painting you should wear some clean gloves so you don't get any of the oil from yer greezy paws on it.
Good luck.
P.S. If you have a compressor, you can get a very cost effective suction type sand blaster from sears (or other places) for about $40. A bag of silica will run you about $3 at most of Menards,Lowes,Home Depot type places. These are a very handy thing to have if you have an outdoor area to use them. Don't forget to wear safety glasses,hat,and somthing over your mouth if you use one of these.