Is there an easy to remove anodizing from aluminum?

DurocShark

Lifer
Apr 18, 2001
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I've got some aluminum (or similar alloy) parts that are anodized. I want to remove the anodizing without damaging the underlying metal. Any suggestions?
 

Bulk Beef

Diamond Member
Aug 14, 2001
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Easy-Off will do it, but don't leave it on for too long. Better to do a few short applications than one long one, and if you leave it on long enough, it will start to eat the aluminum (which might be why the can says "not for use on aluminum").
 

Harvey

Administrator<br>Elite Member
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Oct 9, 1999
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Anodizing is very thin coating of aluminum oxide, the same material as sapphire, rubies, and the abrasive, carburundum. You can grind or sand it off to the bare aluminum below the surface with a fine grit, durable sanding paper. Since it's quite hard, you can't use cheap sandpaper. You'll probably want to polish the surface when you're done.
 

Howard

Lifer
Oct 14, 1999
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Originally posted by: Harvey
Anodizing is very thin coating of aluminum oxide, the same material as sapphire, rubies, and the abrasive, carburundum. You can grind or sand it off to the bare aluminum below the surface with a fine grit, durable sanding paper. Since it's quite hard, you can't use cheap sandpaper. You'll probably want to polish the surface when you're done.
That would damage the underlying metal, would it not?
 

NogginBoink

Diamond Member
Feb 17, 2002
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Originally posted by: Harvey
Anodizing is very thin coating of aluminum oxide, the same material as sapphire, rubies, and the abrasive, carburundum. You can grind or sand it off to the bare aluminum below the surface with a fine grit, durable sanding paper. Since it's quite hard, you can't use cheap sandpaper. You'll probably want to polish the surface when you're done.
But then you expose fresh aluminum to the atmosphere, which will react with atmospheric oxygen, thus forming a layer of... aluminum oxide on the surface.

Really. Pure aluminum reacts with air to form aluminum oxide. The only way to prevent it is to coat the aluminum with something to keep it from the air.
 

Nitemare

Lifer
Feb 8, 2001
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Originally posted by: NogginBoink
Originally posted by: Harvey
Anodizing is very thin coating of aluminum oxide, the same material as sapphire, rubies, and the abrasive, carburundum. You can grind or sand it off to the bare aluminum below the surface with a fine grit, durable sanding paper. Since it's quite hard, you can't use cheap sandpaper. You'll probably want to polish the surface when you're done.
But then you expose fresh aluminum to the atmosphere, which will react with atmospheric oxygen, thus forming a layer of... aluminum oxide on the surface.

Really. Pure aluminum reacts with air to form aluminum oxide. The only way to prevent it is to coat the aluminum with something to keep it from the air.
like aluminum oxide....:D
 

Howard

Lifer
Oct 14, 1999
47,988
8
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Originally posted by: NogginBoink
Originally posted by: Harvey Anodizing is very thin coating of aluminum oxide, the same material as sapphire, rubies, and the abrasive, carburundum. You can grind or sand it off to the bare aluminum below the surface with a fine grit, durable sanding paper. Since it's quite hard, you can't use cheap sandpaper. You'll probably want to polish the surface when you're done.
But then you expose fresh aluminum to the atmosphere, which will react with atmospheric oxygen, thus forming a layer of... aluminum oxide on the surface. Really. Pure aluminum reacts with air to form aluminum oxide. The only way to prevent it is to coat the aluminum with something to keep it from the air.
Anodized aluminum leaves a layer of alumina on the surface which is thicker than it would be if it formed naturally. Maybe he just wants bare metal so he can get a powdercoat done, or maybe even just a normal paint job.
 

Howard

Lifer
Oct 14, 1999
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BTW, the best way is to dip the part in chromic-phosphoric acid. Don't even think of trying this yourself.
 

Bignate603

Lifer
Sep 5, 2000
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Originally posted by: Howard
BTW, the best way is to dip the part in chromic-phosphoric acid. Don't even think of trying this yourself.
I think i've used that stuff before... I used it to dissolve rust off my car. Strangely enough it also dissolves skin...
 

Bulk Beef

Diamond Member
Aug 14, 2001
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Apparently, sodium hydroxide will also work. Try drain cleaner (check ingredients to make sure what you're buying). I've never used it, so I can't vouch for it.

I have used Easy-Off on brand new color anodized motorcycle fork tubes and disc carriers, and it worked like a champ. Can be a little scary when the parts turn black, but that stuff rinses off.

The most important things are:

A. Pay attention while you're doing this. Don't apply and leave it soaking for a few hours, or your part just might disappear.

B. Wash your hands before you take a piss.
 

DurocShark

Lifer
Apr 18, 2001
15,708
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Thanks all... The oven cleaner sounds like a winner.

I plan on stripping the crappy blue off my external drive case, polishing it, and clear coating it. But I've always sanded this sort of thing, and this time would prefer not to.
 

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