I had a new radiator and aircon condenser to paint. I'm not keen on leaving the aluminium bare as the oxidation makes a very good thermal barrier thus reducing the cooling efficient. I got recommend by a car buddy to use frost extreme radiator paint which I picked up from demon tweeks. I dry blasted with glass grit on a very low pressure to prep the surface and remove the oxidation which starts to form within 24hrs. The paint sprays and covers very well, by far the best paint I've used from a rattle can. I only applied one coat and im very impressed with the results