How to rust wrought iron?

A. The specific application will matter, Connie. It is possible to do a "black oxide" coating, which is similar to what you would see on a rifle barrel, although you'd probably have to send it out. But this must be kept lightly oiled, and it won't hold up outdoors or in a difficult environment.

It's easy enough to get cast iron to rust, but how are you going to stop it, and how are you going to keep the rust from rubbing off and getting onto everything? The basic problem is that a natural rust on steel or iron is a fluffy, non-adherent, water-absorbing surface. To stop it, you generally have to apply a clear coat after it, but the clear coat has to reach through the rust to sound metal, or the clear coat and rust will just flake off together.

Good luck, and please spend some patient time with the search engine because we have long and interesting threads on this subject.