Aspis shield - did they ever cover them in copper?

[Dan Howard]

Going thru the materials themselves, I would think it is just as good a material as bronze for it, but I am probably missing something.

The difference between copper and bronze is just as dramatic as the difference between iron and steel. Pure copper is useless as a weapon or armour but bronze was as effective as all but the best quench-hardened steels. I'm talking about proper tin-bronze, not the rubbish that pretends to be bronze today.