Is raw aluminum safe for birds or does it have to be powder coated?
"There must be a beginning of any great matter, but the continuing unto the end until it be thoroughly finished yields the true glory." Sir Francis Drake
No idea about raw aluminum. But when aluminum oxide is refined through electrolysis it becomes a very stable material naturally resistant to corrosion. The whole point of buying an aluminum cage is that it can be washed without any need for powder coating and it never wears off.
My aviary is made out of aluminum. It houses budgies and tiels, but I know people who have bigger birds housed in it. They sell the aluminum for aviaries over here powdercoated, anodized or raw.