How I anodize aluminum

[Jaakko]

Few questions.... Im about to try this using an off cut piece of aluminium not an actual work so could I just suspednd the part using regular electrical wire instead of aluminium wire(dont have Al wire around and im dying to try this)....in theory it works as long as you have current flowing.

Should work, but I'm not 100% sure. Try it out

number 2 is cant you just use salt water as the electrolyte instead of sulfuric acid or is there a particular reason for the H2SO4???
cheers

Nope. (Sulfuric) acid dissolves the aluminium oxide and it is thus needed in the process. Check this: http://en.wikipedia.org/wiki/Anodizing

[Darrylportelli]

Ok thanks jaakko then in theory hydrochloric acid should work too (mentioning it cos hydrochloric acis is cheaper and found in hardware stores easily) since hydrochloric acid reacts with the oxide too: AL2O3(s) + 6HCL(aq) -> 2ALCL3(aq) + 3H2O(aq). If some one tries it out please let us know how it went.

[Jaakko]

Ok thanks jaakko then in theory hydrochloric acid should work too (mentioning it cos hydrochloric acis is cheaper and found in hardware stores easily) since hydrochloric acid reacts with the oxide too: AL2O3(s) + 6HCL(aq) -> 2ALCL3(aq) + 3H2O(aq). If some one tries it out please let us know how it went.

The idea is not to react the aluminium oxide with the acid, but to dissolve it. Hydrochloric acid reacts with aluminum, so it is not a good choice.

[Darrylportelli]

Ok...Trying anodizing right now 10 mins have gone by..ill let you know how it turns out....im using dylon chlotes dye btw

[Darrylportelli]

the aluminium part is turning kinda dark grey....is that supposed to happen???

[danceswithpins]

THANKS!!!! This tutorial is beyond belief. I am very glad you choose to share this with us.

Thanks!!
DancesWithPins

[Ortin468]

[quote="ratyoke"]I told someone I would make this months ago. Well here it is. Better late than never, I guess.


Caustic soda/lye/sodium hydroxide - Different names for the same thing. About the only time I use this anymore is to remove anodizing. This can be found as drain opener, it's usually sold in a granular form. Some of them contain something in addition to the sodium hydroxide. Try to find one that does not contain anything in addition to the sodium hydroxide. I bought some once that was white and blue granules, it didn't work so well. I was told that only the white granules are sodium hydroxide.

If you want a cheap supply of Sodium Hydroxide for removing the anodizing use spray on oven cleaner, the cheaper one, not the fume free. I have used it to take the anodizing off on paint ball gun stuff to polish it up. Spray wait a few,rinse repeat if needed. Just don't leave it on for long periods of time, the surface will pit.


Maybe you can market designer picks in colors nowadays ...lol Nice looking stuff.

[cowbite]

Few questions.... Im about to try this using an off cut piece of aluminium not an actual work so could I just suspednd the part using regular electrical wire instead of aluminium wire(dont have Al wire around and im dying to try this)....in theory it works as long as you have current flowing.
number 2 is cant you just use salt water as the electrolyte instead of sulfuric acid or is there a particular reason for the H2SO4???
cheers

Not that i'm an expert but my experience is that this will not work. The reason being is that you want the current going through the aluminum part and not the so much the wire its hanging from. When you put a regular wire in the bath, attached to the part, the wire goes crazy fizzing and being eaten away...the cathode (lead/alum) also starts to fizz like mad. It looks impressive but you aren't really anodizing the part, just destroying the wire and contaminating your acid.

I had an alligator clip entirely eaten away within 30 mins like this and the part wasn't anodized at all.
I figured that all the bubbles was a good thing but...nope.

cow

[blackjacker2]

GREAT stuff dude!
you would say it come's out of a great shop

[viduata]

A lot of people have asked about acquiring sulfuric acid, and a lot of weird workarounds and low-quality household products have been suggested.

From experience, I can tell you that you can generally buy it from your local chemical supply house for just a few bucks. Believe it or not, it's the single most common chemical in the world, used for an uncountable number of industrial and scientific processes.
I know the idea of walking into a chem supply is weird, but I used to do it a lot in the 90s, and never a worry did I face. Just call ahead and make your order so they can prep it. It's a bit like filling a prescription. "I'll need 1 liter of 16-molar sulfuric acid. It's for use in anodizing aluminum." And you're done. You'll get a higher quality product for less money.

Of course, there will be some distributors that want to see your university ID or something, but these are the minority. Most reagent-grade chemicals are not under any serious gov't control, and there is no reason for them to say "no" to the order if you behave professionally.

And remember the old adage: Do it like you oughta. Add the acid to the water.

Adding water to a liter of high-molarity sulfuric acid can sometimes cause it to get very hot. Add small amounts of acid to water. Use a glass thermometer to check the temp and hold off if it needs to cool.

[HirosStorageUnit]

wow I have an ar15 lower that could use this treatment.

Kewl

[dusanp]

I would so love to try this... but I worry I cant. Well, maybe I will have some luck later...

[Artedo]

Haven't tried, but i believe this post will be of interest. Have a look: www.focuser.com/anodize.html

[C185]

Genius! Wow, I have some many projects to do now...

[mikus]

I have to try anodizing! I was thinking about making pins from aluminium and then anodizing them, could they be put into steel "cage" and anodized in it?