Aluminum against inside of door ok?
I'm changing out the modern mirrors that were on my Spider for original style round mirrors. When the previous mirror was installed, large plastic inserts sort of like drywall anchors were used, so I have 5/16" holes where the original holes were. Looking at some other threads on the Board, looks like Alfa originally used a backing bar with in tapped hole on each end to receive the mirror screws and one in the middle that is attached to the door skin and holds the bar in place. I figured I probably make some backing bars since I won't need to pull the door apart in the future if I need to remove the mirror.
Anyway, to make my life easier, I was hoping to use 1/4" aluminum bar since it's a lot easier to work with than steel. Once installed, the bar pushes up against the inside of the door. Could this cause corrosion in the door? May just be overthinking it. Thanks for the help.