Lbxpdx

I salvaged some old XT thumb shifters and brake levers for a rebuild, but the black anodizing is terribly faded. What is the preferred method of removing the anodizing?

Chombi1 

Better double check whether that's anodizing or just black paint.......

Lbxpdx

It is a mix.

rjhammett

I have used Drano (I use Target equivalent) to remove anodizing. I put some Drano in a zip lock bag along with the part. Watch it carefully because it doesn't take to long. I then put it in water with baking soda to neutralize it then rinse it off well.

merziac

Lbxpdx

I soak in the cleaner and dip in water, scrub very carefully with stainless brush, gloves and resoak as needed.

If its a mix, acetone, stripper would be my first assault.

Steel Charlie

Zepp to strip the anno. Check YouTube. And search anodizing on this forum

Citrastrip for th paint

gugie 

I stripped hard anodizing from a pair of rims once.

Never again. Once you remove the anodizing, you'll have a mottled mess, and you'll want to polish the parts. Polishing will hold up fine until you sweat on them, and then they'll look mottled again.

randyjawa 

I use Extra Strength Eazy Off. Slap on some EO, wait a few minutes (two to three tops) and wipe/water wash the goo off. Repeat as required. Caution - if you leave the EO on too long it will attack the aluminum alloy and that would be an unsolvable problem. Good luck.

mgopack42 

I just wanted to say, that since Drano is lye (sodium hydroxide) which is a strong base, baking soda (a weak base) will not neutralize it. Better is to use vinegar, which is a weak (5% acetic) acid. Be careful whenever working with somethng as strong as lye.
As an aside, I have read that just pure lye from the Ace Hardware store might be better, since it doesnt have all of the additives (scents, surfactants, etc.) that Drano or Easy Off has. Anecdotaly, I have heard this helps with the blotchy, post strip apearance. I have no actual experience, but I read the internet A LOT!

SwimmerMike 

I use Easy Off also. You still need to polish after, but much less work. My first attempt, which looked great when done but a lot of work, was to just sand the anodization off, then go finer and finer until I got to the final polishing compound.

Camilo

I've used Zepp per Youtube and other guides (probably found on bikeforums) and it worked easily and well.

Steel Charlie

So here's what I did not that long ago

https://www.bikeforums.net/classic-v...p-success.html

omijay 

I have looked at a number ot of these recipes form removing anadizing on the forum, and decided there had to be a safer way to do this where I did not expose myself to a bunch of caustic fumes in either my house or my garage. I am a chemist so I ran several tries on some old pieces in my lab.

Here is a detailed version of what I came up with recently after reading someone else's post a few years back about a general description of using sodium hydroxide and vinegar.

It involves two baths and the size of the bath will depend on the size of your parts you are stripping
.
1) Make an appropriate size bath of 5% w/v Sodium hydroxide- This is 5 grams per every 100 ml or 50 grams for every liter (4 cups). You can buy a pound (454 grams) of sodium hydroxide on Amazon for $12.99. So that is enough to make more or less 40 cups of the solution.
2) Make a similar size bath of vinegar, which is essentially 5-10% acetic acid. I used 10% acetic acid, but not everyone has acetic acid at their disposal. So household vinegar is a simpler solution
3) Place the part(s) in the sodium hydroxide bath for 1 minute (You will see bubbles forming don't panic, it will not explode, but there will be some heat generated)
4) Transfer the part to the acetic acid bath for 1 minute.
5) Rinse with cold water and rub with a rag to clean.
6) Place the part a second time in the sodium hydroxide bath for 1 minute.
7) Place the part a second time in the acetic acid bath for 1 minute.
8) Rinse with cold water and rub with a rag to clean.

Notes:
1) There are no fumes to worry about breathing in.
2) I would wear some plastic gloves
3) You can reuse the solutions several times, but you might want to store them in a sealed bottle. Particles will settle on the bottom so you can decant them away
4) Plan on polishing a lot if you strip the parts. Maintaining beautiful shiny bike parts requires work.

reconnaissance

Just want to point out that actual true anodizing penetrates into the surface of the aluminum and serves to prevent corrosion and also hardens the aluminum as far as the anodization penetrates. So the best course depends on what the goal is. If it is just color change, then a good, durable paint in the color of choice is best. Actual removal of the anodization, weakens the item (somewhat). There are other surface colorization methods, which aren’t actually anodization. Chipping is a condition of painted parts. Fading to lighter color, (purple, gray) is true anodization affected by sunlight.

Sorry to complicate things, but accuracy is important to some folks.

icemilkcoffee 

What is the best way to mask off threaded holes or machined holes if you don't want the lye corroding the threads or precision machining?

Velo Mule

It looks like the brake levers that @Lbxpdx is posting a picture of looks to is painted black. The black paint is in poor condition.

Use paint remover to remove the black stuff. Follow up with sanding, Scotchbrite or similar abrasive.

It is also possible that this is powder coat, but it look like paint to me.

Whether there is anodizing on there I cannot say. But once you have the black off, you can repaint if that is your goal. If you want to get a polished finish and think that the finish is anodized then you can follow one of the above solutions.

By the way, there is a way to check if a piece of aluminum is anodized or not. Aluminum is electrically conductive. If you have a multimeter, set it to ohms and place the two probes on a the surface of the aluminum part. If the aluminum surface has no anodizing the reading will be under 2 ohms. If the part is anodized it will be well above 2 ohms, likely in the k-ohms range or higher.

Don't insert the points of the probes into the surface because the sharp point may penetrate through the anodized layer. Just touch the surface.

Steel Charlie

It is always interesting to see the lengths people will go to in making something really simple really complicated.
JMO of course

SurferRosa

That's true with rims (IME). I tried it once with a rim, and it simply wasn't worth all the trouble. And who wants to keep a deanodized rim polished and looking perfect? That's a component that attracts all kinds of road mess.

On the other hand, I've found every other deanodized component super easy to keep polished and looking great. But I don't ride in the rain.

omijay 

I tried to minimize the time the parts were exposed to either the basic or acidic conditions. I also tried to neutralize as fast as possible.

I have not had any trouble with threading after the treatment, but I see where this could be a concern on delicate threading.

One simple solution might be to fill the threads with a layer of petroleum jelly/vaseline during the treatment. This would act as a waterproof
barrier that would be easy to wipe off.

Someone might have a better idea, but this would be a cheap and safe option.