Many older homes have radiant heat. Radiators are very heavy and after a while they can look very unattractive. The hardest part of restoring a cast iron radiator is getting it out of the house so you can work on it outside or in an outdoor shop. Newly restored radiators add to the character of an older home and today's paints make them more efficient to use.
Start this project at the beginning of the summer. Allow plenty of time to do the work of restoring the radiators and also to give the freshly painted radiators plenty of time to cure before using them in the cooler months.
Get a friend or two to help you move the radiators outside. Be careful since radiators are very heavy. Use a wheeled dolly to help you move the radiators to and from the house.
Sandblast the radiator to remove as much of the previous paint as you can. Use a wire brush to work on the stubborn or hard to reach parts.
Call local auto machine shops if you do not own a sandblaster. Find out which machine shops have dip tanks. Ask them to dip your radiators which easily removes all the paint and rust.
Cover the radiator with a spray on zinc primer. Priming your radiator helps the paint to adhere better and also makes the paint job last longer.
Brush on an oil-based paint. Be careful to get into all the grooves and in between each section. Allow the paint to dry completely. Remember that oil-based paints take longer to dry than water-based.
Apply a second coat of paint if necessary.
Re-install your radiators in the house. Give them at least two weeks for the paint to cure before starting up your heat. Turn on the heat for the first time after the new paint job on a day when you can open the windows, since the first time the radiators heat up they will smell strongly of paint.
Do not use a metallic paint as it decreases the amount of heat that the radiators put out.