Removing Anodizing From Aluminum Quickly and Easily.

I dislike the color of many anodized parts and tools, and I love the look of bare aluminum. Fortunately, it's easy to remove the anodized coating from most things.

I first heard about this here, but I found their instructions lacking.

The pictures below show what we want -- and what we have.

Step 1 Materials.

You need:

1. Some Greased Lightning Cleaner.
2. A plastic dish of some kind.
3. A brush.
4. Something with a coating that you just can't stand. I had a new folding knife which was a particularly nasty shade of olive drab.

Comments

[junits15]

oven cleaner works well also, but its really nasty stuff

[spyderbyte]

I have heard that both drain cleaner such as Draino and oven cleaner will remove the anodizing on aluminum. I am re-finishing the aluminum trim on my antique automobile and have been told that once you have removed the anodizing the aluminum can be polished and then protected with a clear spray plastic sealer. I've seen the finished product and was impressed. Does anyone know what to use for the plastic sealer to maintain the polished look?

[deega]

No need to scrub.  Just get some drain cleaner (sodium hydroxide), the granule type, and mix with water to whatever strength you desire.  Dip the anodized part into the solution for about 15 seconds and rinse with fresh water.

[tubbychick3n]

Great 'ible! I would have never thought that something like this was possible until i saw this. +4.5!

[sr1sws]

I think what you really did was remove the dye, not the anodizing. The anodizing is actually aluminum oxide - which if you look it up, is one of the various abrasives used in sandpaper etc - e.g. "it's hard". I don't think a simple cleaner removed it... of course I'm surprised it removed the dye, so I don't know for sure ;-D Anyway, it WAS an ugly color!

[daniel_reetz]

Actually, you'd be surprised -- you can remove aluminum oxide with pretty much any caustic. Most people use oven cleaner, which contains sodium hydroxide (lye). Just like you, I doubted that it would work -- so before I spent the money on Greased Lightning I called my dad (he's a chemist) and he assured me that any base should eventually destroy it. I can ask him for the reaction and post it here if you're interested. Might be a nice addition to the instructable.

[plasticbiker]

Actually, reading the link you included, this process oxidizes the aluminum, which softens the anodizing. You need to sand and polish the aluminum to get rid of the white Aluminum Oxide.

[daniel_reetz]

The first step in the commercial production of aluminum is the separation of aluminum oxide from the iron oxide in bauxite. This is accomplished by dissolving the aluminum oxide in a concentrated sodium hydroxide solution.

From my dad, a chemist:

"Aluminium oxide reacts with a solution of sodium hydroxide to yield a solution of sodium tetrahydroxoaluminate. Al203+2NaOH+3H2O --->2NAlOH4 "

The whiteness of this surface is due to the bead blasting that they did pre-anodizing.

[daniel_reetz]

Ah, Google is my friend. Here's the reaction with sodium hydroxide. I'll check the MSDS for Greased Lightning and figure out the active ingredient.

[daniel_reetz]

The MSDS (material safety data sheets) for Greased Lightning indicate that the active ingredient is sodium hydroxide. There's also a "proprietary surfactant" which probably increases the speed and efficacy of the reaction between the aluminum oxide and sodium hydroxide.

Sweet.

[dchall8]

I wonder if ammonia would do it...maybe take longer.

[Scott_Tx]

You should note that the surface anodizing hardens the surface of the aluminum. Scratch prevention and all that. But aluminum is self anodizing on exposure to air so it'll eventually turn gray and take on light surface hardening again.

[daniel_reetz]

Good point. I did leave out the fact that it will self-anodize a little, and that this process definitely reduces the scratch-resistance of the surface. However, one good thing is that if you scratch the surface, the underlying material is now the same color. Hence scratches are much less obvious.

[misformiche]

agreed. dead sexy... roar.