How to Sand-blast Cast Iron Radiators
once you have removed your radiator and brought it either outside or in your garage, you will need to make sure the rust is just surface and not deep. if it is deep you must replace your radiator.
now that it is checked you are ready to sand blast it. hold the sand-blaster away from the radiator about 6-8 inches and adjust the tip so the spray is about 2 inches wide.
the most challenging part of sand-blasting a radiator is getting into every nook and cranny. this can be achieved by shooting the sand through every hole and in every direction.
from my experience the paint used on radiators will lift of pretty easily when sand-blasting. some paint may not want to come completely off, but just make sure you rough it up enough to repaint. also insure it is not to thick. if it is you will see it when you repaint. once you have finished just hose down your radiator to get rid of excess sand and dust. now your are ready for paint.