Try aluminum conduit, aluminum oxide doesn't scale off like copper's.
Aluminum is actually the best conductor, copper is the cheapest conductor.
Correct me if I'm wrong, but isn't copper usually like 5 times more expensive than aluminum by weight? Most recent time I was at the junk yard copper wire was going for just over 5x what cast aluminum was per lb.
or is aluminum conduit just more expensive than copper due to manufacturing issues? I'm just curious.