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.
Should I read that the anodizing off the frame and rims
Kind of figuring this out I build motorized bicycles and I stripped the emerald eyes off my bicycle frame and rims wet sanded and polished my aluminum looks like Chrome and the wax seems to protect it pretty well from what I read you saying that mind frame and rims will deteriorate
<p>Hello, I am a chemist that works in a metal finishing shop and we anodize parts for aerospace and the military. I'd like to shed some light on this process but I would pose some questions and information first.<br>1) why would you want to take the anodize off? Anodizing protects aluminum from corrosion. Without the coating, aluminum will corrode over time (white splotchy appearance) and will ruin the whole purpose of the item being used. If you don't like the color, why don't you buy a knife with the color you want? or without color? You can get anodized Items without a color and have them still be protected.<br>2) Bare aluminum will protect itself from the environment by forming a very thin layer of aluminum oxide (which is the same component of an anodized surface) but that will hardly protect itself from corrosion.<br>3) Stripping the anodize will also cause the material to change dimensions. When you anodize a part, the bare part will be a little smaller dimensionally before it gets anodized. The manufacturer does this on purpose because they know that anodizing will increase the thickness of the part evenly on all surfaces. Removing the anodizing changes its dimensions by making it smaller and then you will get other problems like..<br>4) The sheath not fitting correctly and the hardware attaching the knife to the sheath not fitting correctly. The manufacturer designs the part with a very high tolerance (like within 0.0002&quot;) to make sure everything fits correctly. If the hardware attaching the knife is too loose (because you stripped the anodize) your knife blade might fall off when using it. Also, the sheath might not fit correctly and will cause the knife blade to be exposed to the environment which will cause the knife blade to corrode. All of these are bad. <br>5) From your pictures and notes you said it was &quot;HAIII&quot; which means it was Type III anodized or &quot;hard anodized.&quot; Hard anodizing produces a harder more abrasion resistant coating than Type II anodizing (&quot;regular&quot; anodizing) but from looking at your pictures, the original sheath doesn't look hard anodized. Hard anodized coating will come out very dark. Depending on the alloy it will be dark brown or dark grey. Another issue is that hard anodizing produces smaller pores (look it up) that makes it very difficult to accept a dye color. Most of the parts we do here that are hard anodized will only accept a black color. Any other color makes it look weird. If the knife manufacturer said the sheath is &quot;hard anodized&quot; they are either lying or the coating is so thin, that its abrasion resistance will be the same as regular type II anodizing. <br><br>That out of the way, if you still want to remove the anodize, the best way is to use a drain cleaner of some sort. Drain cleaners have sodium hydroxide (caustic soda) and/or potassium hydroxide. **CAUTION! THEY ARE VERY NASTY AND CAUSE BURNS!!** Be EXTREMELY careful when handling these chemicals. When immersed, the part will bubble vigorously. You probably won't need to scrub if the drain cleaner is strong enough, plus that could cause the chemical to splash and you don't want that. <br>Once all the color is gone, if you just wanted to get rid of the color, you're done. Just wash off with PLENTY of water and dry it. If you want to remove all of the anodize layer, youre going to have to get a continuity meter/tester.<br>The aluminum oxide of the anodized layer is an insulator. This means it does not conduct electricity. A continuity meter checks if there is an electrical current flowing through objects. Attach the part you're checking to something conductive like steel or copper or maybe a piece of aluminum foil (make sure they are both touching). With the continuity meter clipped to the other metal, touch the tip of the meter to the part. If the light turns on, there is current flowing to the part and all the anodizing has been removed. If not, there is still coating on it and you have to strip it more. <br>You CANNOT re-anodize a part unless all the coating has been stripped off. You might be able to get the bare aluminum look (as opposed to the white above) if you polish the part again but usually it won't become bright and shiny again. Of course, you can always send it to a metal finishing shop and let the pros do it :)<br><br>Sorry for the long response but I like to educate :)</p>
<p>Useful info, but sometimes it is necessary to get to the SOFTER aluminum below the anodizing. For example the mounting rings for a rifle's scopes can sometimes slide back due to the force of the ammo being fired repeatedly. If the anodizing is removed and then the rings are remounted to the rail they are less likely to slide back over time causing the scope to no longer be zeroed in. Small area of aluminum oxidization right at the connection may actually help to hold it better. Aluminum oxide Al2O3 is insoluble in water, fairly hard and useful stuff once it forms around the joint, not as attractive or good as the if you could Anodize it but good enough.</p>
<p>Hey <a href="http://www.instructables.com/member/GmoTheChemist/" rel="nofollow">GmoTheChemist</a> , Thx for the comment really help full, I am looking to de anodize a part to gold plate it , any more tips , like how long to keep in drain cleaner? </p><p>etc </p><p>regards </p><p>syed </p>
<p>Hy SyedN2, unfortunately, aluminum is the hardest metal to plate on because of it's tendency to oxidize with the air (see point #2 above). To strip off the anodize, use the procedure above and you'll have to do the continuity test to make sure you removed all of the anodize. Time in the solution depends on how thick the anodize coating is. There is no real set time, it just all depends. </p><p>To replate, there will have to be some additional steps involved. The best method is to take it to a decorative plating shop and have them do it. They have the expertise to do it right the first time. Proper steps would be to clean/degrease the surface, deoxidize the surface using an acid step (50% nitric acid BE CAREFUL) and then the key part is you have to use whats called a &quot;zincate&quot; step. The zincate coats the aluminum with zinc hydroxide which protects the aluminum from the air so when it goes into the next tank, the plating will actually stick. After the zincate step it either needs a copper strike (thin copper plating layer) or an electroless nickel strike (thin nickel layer) you can plate the gold on top of the nickel. </p><p>I assume you wanted to try one of those home gold plating kits. I can assure you that they probably won't include the copper strike/electroless nickel strike or the zincate step. You can ask them if the kit can plate over aluminum but I would doubt it would actually stick. I would just take it to a plating shop.</p><p>Cheers,</p><p>GmoTheChemist</p>
<p><a href="http://www.instructables.com/member/GmoTheChemist/" rel="nofollow">GmoTheChemist</a> -</p><p>Yeah I see that now , I think I this would be a bit out of my league.</p><p>Was actually looking to gold plate my iPhone , why did thees things have to be made out of aluminum ! :P</p><p>I guess the crazy prices they charge for plating phones makes a bit more sense now.</p><p>I used to think it was a straight forward process.</p><p>You have been a grate help for me in understating some things I had no Idea about. </p><p>Thanks a lot! :)</p><p>Regards, </p><p>syed </p>
<p>You could have it re-anodized in a gold color...It would still look pretty cool! We have a gold color here at our shop. I'm sure you could find one close to where you are located. :)</p>
<p>I too prefer the clean aluminum look, I never new something like this existed. Thanks for the tutorial!</p>
I don't thing you removing the anodized surface. It looks like your just scrubbing the dye out of the anodized surface, as anodized aluminum has large amounts of microscopic pores and that's what enables it to be dyed so readily. The aluminum oxide(anodized surface) is harder than most steels (that's why its used in most grinding wheels and sand paper), albeit very thin, and scrubbing with cleaner and a brush would not scratch through it.
<p>Dan,</p><p> Just got a quick question for you. From what I could see in the picture, the brush didn't leave any scratch marks while removing the anodizing, but I still want to ask, did it scratch it at all? I'm working on something that I don't want scratches on. Hence why I don't want to use sandpaper.</p><p> Thanks.</p>
One thing you can consider, is using a plastic brush, which will definitely be softer than any metal or anodized finish. I got a pack of plastic bristle brushes from Harbor Freight for a couple bucks. In my case it definitely didn't scratch it all, but to be honest, I barely needed the brush. I'm still using this knife-- it's in my pocket right now and the scratches on it are fro sloppiness, not from removing the anodizing color. Good luck with your project, please let me know how it turns out
Will do. I was thinking of trying sandblasting first to be honest. I love the speckled finish afterwards. Either way, ill post pics when it's done.
<p>Very helpful article and thread. Thanks a lot. </p>
<p>Hi Daniel,</p><p>I'm really happy to have found this instructable. Although I do have a question:<br>Once the dye is fully removed, can I just dye the aluminum another color?</p><p>I'm currently debating of deanodizing the alloy parts of an RC car chassis and change it to a different color. Could I just follow your procedure and dye it with clothing dye?</p>
<p>Tried liquid plumber, couldn't get Lye at grocery store at 8PM on a Sunday. Soaked my 1965 headlight bezels in the stuff straight and it didnt do squat. I soaked for another hour and the anodizing is finally starting to feather off with sandpaper. Fast, I wouldn't say that. Easily? Not with Liquid plumber and it did contain Sodium Hydroxide. So maybe I got some weak sauce...Ill soak overnight. Even a sanding flapper wheel on a die grinder didnt just wipe this stuff off! </p>
Sodium hydroxide is also know as Lye, which is used to make soap and is also used in things like oven cleaner and other heavy duty cleaners. You can buy pure lye in flake form, used for clearing drains, at most hardware stores. Mixed with water, it will strip anodizing.
Thank you for this. The <a href="http://www.vaughnmetal.ca/" rel="nofollow">metal finishing</a> on a lot of my knives is getting bad from all of the anodizing. I hope this works and thank you for posting this.
Hey, sorry I forgot to report back. The Multi-Purpose did not remove the anodizing, but it did change the surface texture of the metal.
Thanks for posting this! I had no idea removing this kind of <a href="http://www.vaughanmetal.com/" rel="nofollow">metal finishing</a> could be so quick and easy.
I know this post is old, but I have one question. Can I use Multi-Purpose Greased Lightning, or do I have to use the Auto and Shop that you used?
I don't know - but please report back if the Multi-Purpose works for you.
Hello guys ... I know it is a very old post but may be someone can reply ... I hope daniel_reetz is still around :-) <br>As you might already heard about anodize coating on the back aluminium of black iPhone 5 is susceptible to scratches. I've already dropped it once and got nasty marks on the corners. I'm thinking about removing this black anodized coating myself. What is the best method to do that, considering that I can't dip it in something? It has to be removed neatly and completely. Another thing I wonder is would I get a nice silver aluminium (like MacBooks) or some greyish silver aluminium? <br>
That's a very interesting idea, but I have no good idea on how to do it. Even the mild solution I mention here is a bit corrosive, so you definitely don't want any going inside the phone. Perhaps applying it with a slighly dampened Q-tip could control the fluid enough to make it work. I can tell you this, it will take time. Good luck!
Thanks for replying daniel. Couple of more questions :-) <br>Would a mild solution have any effect on plastic parts? <br>You said &quot;it will take time&quot;, are we talking about minutes or hours? <br>Your knife appears white after the treatment not silver, like aluminium, why? <br>One comment below said &quot;I think what you really did was remove the dye, not the anodizing&quot;. Does that mean my phone's back might not actually become silver?
...or you could just use paint remover...I accidentally discovered this today D:
I just soaked grease covered anodized parts in Lestoil to remove the grease and tar. It started foaming after 10-15 minutes and after 30min it had removed the red anodized color. I'm not sure if it is just leaching the color or stripping the anodized layer. Does anyone have any idea how/why a cleaner like Lestoil would have this reaction? It seems weird that a grease cleaner safe enough for laundry and mopping would have the power to do this.
oven cleaner works well also, but its really nasty stuff
oven cleaner is terrible. a few years back on a news program here in sydney a lady got some on her skin and it literally ate away at her flesh. she had a good 2 inch deep crater in her calf muscle. it was terrible
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?
No need to scrub. &nbsp;Just get some drain cleaner (sodium hydroxide), the granule type, and mix with water to whatever strength you desire. &nbsp;Dip the anodized part into the solution for about 15 seconds and rinse with fresh water.
Great 'ible! I would have never thought that something like this was possible until i saw this. +4.5!
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!
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.
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.
<em>The first step in the commercial production of aluminum is the separation of aluminum oxide from the iron oxide in bauxite. <a rel="nofollow" href="http://scifun.chem.wisc.edu/chemweek/aluminum/aluminum.html">This is accomplished by dissolving the aluminum oxide in a concentrated sodium hydroxide solution.</a> </em><br/><br/>From my dad, a chemist:<br/><br/>&quot;Aluminium oxide reacts with a solution of sodium hydroxide to yield a solution of sodium tetrahydroxoaluminate. Al203+2NaOH+3H2O ---&gt;2NAlOH4 &quot;<br/><br/>The whiteness of this surface is due to the bead blasting that they did pre-anodizing.<br/>
Ah, Google is my friend. <a rel="nofollow" href="http://www2.uni-siegen.de/~pci/versuche/english/v44-10.html">Here's the reaction with sodium hydroxide</a>. I'll check the MSDS for Greased Lightning and figure out the active ingredient. <br/>
The <a rel="nofollow" href="http://www.greased-lightning.com/products/MSDS.aspx">MSDS (material safety data sheets) for Greased Lightning</a> indicate that the active ingredient <em>is</em> sodium hydroxide. There's also a &quot;proprietary surfactant&quot; which probably increases the speed and efficacy of the reaction between the aluminum oxide and sodium hydroxide. <br/><br/>Sweet.<br/>
I wonder if ammonia would do it...maybe take longer.
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.
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.
agreed. dead sexy... roar.

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Bio: Hacker, Artist, Researcher, and founder of the diybookscanner.org community.
More by daniel_reetz: Bargain-Price Book Scanner From A Cardboard Box. DIY Camera Array 2: Computational Refocusing With Just One Camera Removing Anodizing From Aluminum Quickly and Easily.
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