Mesa,
If you must use paint on Aluminum alloy parts ....
1. Strip the parts to base metal with plastic media in a suitable blast cabinet.
2. Wash the parts with 100% Isopropyl Alcohol.
3. Etch the parts with ALUMIPREP (follow label instructions

)
4. Alodine the parts with ALODINE solution.
5. Prime the parts with 2 part epoxy, zinc chromate primer.
6. Topcoat with a 2 part epoxy paint, JET GLO, ALUMA GRIP, or IMRON.
Or powdercoat the parts. Powdercoat will not be as durable though.
Best Regards,
Scott