Some tips for painting wrought iron include covering nearby objects to protect them from paint spray, removing the old paint and rust, applying the primer and then the paint. Painting should be done on a warm, dry day, when temps are higher than 50 degrees Fahrenheit and the humidity is less than 80 percent. Don't paint directly in the sunlight.
If you are painting a wrought iron chair or table that can be moved away from other structures, this is the ideal solution. It just needs to be set up on tarps or ground cloths anywhere in the shade. If a fence is being painted, cover background areas completely to avoid paint over spray.
The old paint and any rust must be removed before the new paint is applied. Sanding, scraping and using rust remover products are all options. By the time the piece is thoroughly cleaned and dusted off it should be down to bare metal.
Primer coats the metal, giving the paint something more substantial to cling to. The primers and the paint are typically sprayed on, but some types of primer may be applied with a brush. The latter typically takes longer and may need two coats.
After the primer has dried for at least 24 hours, the first coat of paint should be sprayed on, followed by the second roughly an hour later. Spray wrought iron paint achieves even coverage. Some brands of wrought iron paint don't require the primer, which makes the job easier and faster.