I have painted,decorative posts holding up my patio roof. I stripped one and found out it is aluminum (they look like wrought iron). When I researched how to prep the aluminum for painting I got info on etching and harsh chemicals to prepare the aluminum to take the paint. There must be an easier, less toxic way to prime these posts. The posts are sitting on epoxy stone so I have to be careful about protecting that surface. The posts are exposed to the weather. I live in the mid-west where temps can be +100 to -10 degrees, although usually not in the same day!