The best metal for the job is steel. Hands down, it's the best.
Well, unless you nick it too deeply through its zinc oxide protective layer and it begins to rust - unless you're looking for the rust look.
Like discussing, what the best wood is for outdoor signs, the best metal for outdoor signage is less about the material and more about the branding and message.
...there are several ways to structure and support aluminum to keep it from becoming a hazard. With trusses, framing, and other methods, can keep aluminum looking bold and secure through the stiffest winds.
Aluminum doesn't need to be supported with other metals. Plastics and wood can be used to provide reinforcement.
Paints, stains, spackle, soldering, welding...it's both art and science.
As with aluminum above, when you pick a metal, it isn't always about durability. It's look and feel can also come into play. You want it to portray a certain identity, a metaphor for your overall brand. It's that simple.
As for the, "how to get it to last," well, that depends on signmakers like us. With over 30 years of experience, we can make the metal of your choice stand out. All we have to do is design the sign you need.