question about aluminum

[DwightSchrute]

i'm kinda embarassed to be asking such a newbie questioin, but i figured if anyone would know, it would be you guys.

my question is,

Can the gorillamaxx stuff rust? or would it just tarnish?

thanks people!

[phildogg]

alum doesn't rust. It may get hazy.
phil

[_paralyzed_]

can't rust. aluminum is a non-porous metal. No pores to let in oxygen or water. Peace

[redshift]

Every metal is porous, but only iron or certain iron-containing alloys will 'rust'.

Aluminum oxidizes, which is a protective layer actually. You can polish, sand it etc. and the oxide will immediately re-form.

So you can sort-of call oxidation "aluminum's rust" but it's only billionths of an inch thick, and will not corrode like iron will. It does corrode, but in a normal environment this will take decades or even centuries...

[DwightSchrute]

thanks guys, much appreciated.

[_paralyzed_]

Originally Posted by redshift

Every metal is porous, but only iron or certain iron-containing alloys will 'rust'.

Aluminum oxidizes, which is a protective layer actually. You can polish, sand it etc. and the oxide will immediately re-form.

So you can sort-of call oxidation "aluminum's rust" but it's only billionths of an inch thick, and will not corrode like iron will. It does corrode, but in a normal environment this will take decades or even centuries...

I sit corrected!

[brushlessboy16]

Originally Posted by _paralyzed_

I sit corrected!

lol


All metal (aside from gold and a few others) corrode, and oxidize.. aluminum oxide is easy to beat- some metal polish and a little elbow grease

[redshift]

The worst corrosion will happen with cast metals, they are more porous. Billet is less porous and more uniform, so polished billet will stay pretty a long time. Anyone who has tried to polish rough cast wheels knows it is all but impossible. Smooth cast is polishable, but won't usually hold it's luster very long.

Really unless it's in a corrosive environment, aluminum is a 'forever' metal, like better grades of stainless steel is.

[Bondonutz]

Jason,
Now when Aluminum and say Stainless are bolted together and the aluminum corrodes is that a form of "Electrolysis" or plain ol' corosion or one in the same ?
I ask because when I was still working on buses and had to take something apart that had ben together for years and exposed to enviroment sometimes the the Stainless would be eaten away and the Aluminum would be heavily pocked up from the corrosion in form of white scaley chaulky gunk.

[redshift]

That's bimetal corrosion, which I don't understand the chemistry of, but it's a matter of different metals' reactivity with the environment, and states of "charge". I've come across that myself a number of times!

But it also could simply be an area where corrosive material got trapped, and once one metal started corroding, it becomes more agressive against the other. That's about the best explanation can give you without boring you to tears lol.

[What's_nitro?]

@Bondo: Differential metals will always have some type of charge between them when they are exposed to each other. That's how a thermocouple works. I'm not positive on the actual chemistry involved but I would assume it had something to do with the stainless being corroded away.

Edit: Redshift.....

[redshift]

BLINDSIDED

Sorry! I guess that either proves both of us know our sheet, or neither?

[What's_nitro?]

True... Or false?

[redshift]

"I am faster than BL."

Alright what's that about?

I've seen some tall claims in my day, but mister I got a problem believin' that thurr...

[What's_nitro?]

Hahaha I don't need to prove myself to anyone!