|
Why not just leave the gate unpainted? Putting a finish on aluminum that will hold up is a lot of aggravation. For the best possible corrosion resistance, you need to clean, etch, alodine and prime the metal prior to applying a topcoat. Alodine is nasty stuff, you can simplify the process if you use a self-etching primer. I suggest that you go to an automotive paint store and use whatever they suggest. Here's how I prep aircraft parts: 1. Clean the part using soap, water and Scotchbright. The part is clean when de-ionized rinse water runs off the part in sheets, rather than beading up. 2. While still wet, dip in Alumiprep 33, which is a phosphoric acid-based cleaner/etcher, for about 3 minutes 3. Rinse in de-ionized water. 4. Dip in Alodine 1201 for about five minutes. 5. Rinse in de-ionized water and dry. 6. Prime with epoxy or zinc chromate primer. 7. Finish with whatever topcoat you like. Alodine and Alumiprep are trade names, most paint companies like PPG sell their own versions of these products. The problem with aluminum is that it starts to oxidize the instant bare metal is exposed to air. This oxidation is what protects it from further corrosion, but it also prevents paint from sticking. Hence the need to etch and alodine, or to use a self-etching primer.
| 
