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View Full Version : Aluminium passivation - for aluminium to be used outside



CHudson
05-04-2011, 06:23 PM
I'm building small parts of aluminium (6086-T6) for use outdoors. I'm trying to work out how to best seal the aluminium but I'm struggling to find any information. I want to be eco friendly as possible so would ideally prefer not to plate or anodise if I can avoid it.

I was hoping that using Desmut then boiling the aluminium would be enough.

However, speaking to one company who both sells and anodises aluminium reckons that to prevent corrosion I have to anodise. Where as Gateros Plating says that desmut and leaving in the air is sufficient.

Any ideas or any professionals out there that can give me advice on this? I just don't want my aluminium to corrode.

Thanks

birchy
06-04-2011, 08:14 PM
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.

CHudson
06-04-2011, 08:28 PM
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.

birchy
06-04-2011, 08:33 PM
Have you got extremely salty rain where you live? The fence posts down one side of our garden are made from 2" diameter aluminium tubes. I'm assuming they are ex scaffolding poles. They're not anodised or otherwise protected. They've been there for over 30 years and show no signs of corrosion or pitting, etc...

CHudson
06-04-2011, 10:18 PM
Thats good to know. Dont have any salty rain or anything but I intend on selling these parts so I need to ensure there suitable for purpose etc