Aluminium passivation - for aluminium to be used outside

[CHudson]

Aluminium on its own is not corrosive. It will only corrode when in contact with other metals such as steel bolts, etc as this triggers a Galvanic corrosion. So unless you are using dissimilar metals, there's no need to protect the aluminium as it has a natural oxide protection layer.

Its funny, i keep getting conflicting information. Some people have said that it will corrode badly in a salt water atmosphere reuslting in pitting and wearing away. I think Ill have to test this by using various peices of ally, non anodised, anodised, clear laquered etc and put it into a salt water mister for a week.