Carl,
I just received a new aluminum radiator for my 1949 3100 1/2 ton truck. The silver coating you are referring to is a light coat of aluminum spray paint to prevent corrosion during shipping. I spoke to the a technical representative with Eastwood Company and was told in order to paint the radiator it would need to be cleaned with aluminum wheel cleaner. I used Mequires Hot Rims aluminum wheel cleaner. Lightly dry the sides and tanks and set it in the sun to dry the core. Use a 3M red scuff pad to scuff the tanks, sides and necks. Then use a clean dry cotton cloth (old t-shirt) with acetone to remove the dust, any oil or grease and residual aluminum paint. Let the radiator dry completely. I purchased the radiator black paint from Eastwood in the satin finish. They also have a gloss finish. I sprayed the complete radiator with 3 light coats (2 spray bombs). The tech advisor with Eastwood Company told me NOT to use any metal etching primer or the paint would peel. Just spray the radiator black directly onto the scuffed aluminum. Cleanliness and preparation are your friends here. Let the radiator dry for 3-5 days before install and this paint will harden and stay put. Painted mine and it turned out GREAT!! Hope this helps. If you have any more questions, let me know.
Tim
