Radiators are common heating elements in older homes. They come in many shapes and sizes and can use different heating systems. What is common to all radiators is that eventually their paint ages, and it becomes necessary to repaint them. It's best to paint a radiator in the early summer or early fall, before you need to close the windows on the house since you must bake off the odours of fresh paint.
Remove any drapes or objects that are close to the radiator. Place plastic sheeting around the radiator so that debris and paint are contained to the area around the radiator.
Sand, scrape and brush the radiator to remove all loose paint, dirt, debris, wedged objects or anything behind the radiator. Rough the finish surface with sandpaper.
Wipe the entire radiator down with Willbond degreaser.
Spray or brush on a zinc chromate primer so that the entire surface of the radiator is primed. Primer sticks to the metal and paint sticks to the primer so any untreated surface won't hold the paint as well. Allow the primer to dry 24 hours.
Paint the radiator with an oil-based paint, which is available in both spray and brush on types; either will work. You may need several coats to create the appearance you want. Allow the paint to dry 24 hours.
Open your windows. Turn on your radiator heat system. Allow the radiator heat to bake the paint. This is often smelly and uncomfortable and best done when you can leave windows open, and fans can direct the stink outside. When the odour is gone, turn off your radiator until it is needed in the winter.
Even though you bake off the paint odour, some residual will remain, and you may need to air out your rooms a few times over the winter to completely remove the smell.