My neighbor used bake on ceramic paint on his chimney flue pipes. He followed the procedures accurately and his pipes are still a nice matte black after 15 years. Recently he did another section of pipe with VHT and it is holding color very well thru two winters.
I agree, sand blast the part completely bare first. Wear some of those surgical type gloves when handling the part after blasting to keep it super clean. Then it is good to heat the part to 200 F first and let it cool off to about 100 F in a dry environment before painting. Lastly I would shoot a bunch of pure denatured alcohol all over it while it is warm and let that dry really well. Then follow paint and cure procedures on product.
Preparation steps are super important.
You may look at ceramic stove pipe paint as an option.
Heck, I sand blasted a set of generic headers, washed them with denatured alcohol and painted them with a can of 97% pure galvi-paint from ace hardware and it lasted 4 years in a light grey color before little spots of surface rust started showing. And all that paint contains is lacquer thinner and zinc.
