Tommy Mooney
David ! Your best bet is to get a fairly light sandpaper (120grade) and whilst wearing a mask , sand down the radiator until any loose paint is gone and radiator is smooth. Then depending on the finish of paint you'd like (satinwood/eggshell?) I would give a coat of zinsser (stain block and primer) then top coat using ordinary oil based paint . A radiator paint is not required . Alternatively , hammerite paint is available in white gloss and can be applied directly to rust . I hope that's of help , Tommy
