The most widely used aluminum, 6061 is fabricated into everything from pipe fittings and containers to automotive and aerospace parts. It is strong and corrosion resistant, plus it's easy to machine and weld.

1000-, 3000-, and 5000-series aluminum alloys stand up to salt water, chemicals, and weather better than other types of aluminum. They're also the easiest to form and weld, so they're often made into storage tanks, architectural trim, awnings, and fan blades.