Use two-hole compression connectors with self tapping screws and star lock washers. Use a wire brush wheel on drill motor to prep the area, and use a oxidant inhibitor on mating surfaces like Sanchem No-Ox-ID A Special. The stuff will last 50 years even with sea salt spray exposure (Golden Gate Bridge) . Water ,Bridge, POCO and Telco utilities demand it to be used. Really good stuff and cheap.
Dereck, what about Copper Shield or Penatrotx E. Both are copper compounds in oil. I use this on electrical connections and threads.
Its messy though, and "gets home before you do"