Removing Annodizing

[proffighter]

Originally Posted by stormin48061

Profighter, are u saying I left the oven cleaner on too long? I sanded some of the black spots with 600 grit water and it seem to remove the spots. How long should I leave the oven cleaner on? I'm on the verge of going down to my friendly lab and getting some sodium hydroxide and now maybe some nitric acid....

No I say don't use oven cleaner at all. Poor if any control and simply not made for this. To much contamination by other chemicals do lead to a maybe bad result. Use correct chemicals in a bath, part completely under fluid, check the process and then dipp immediatly into destilled water. leave a few minutes and then flush with destilled water. If black (due the alloy) dipp into nitric acid and after a few seconds the part is clean. Flush again.

Check this site for details (a guide in english is there too):

Electronic Thingks - Anodising guide

[Elombard]

I have not looked around yet but can I get these chemicals at the hardware store?

[Josh D]

Just an FYI, your local dollar store will have sodium hydroxide oven cleaner for a buck under various generic names. Same as Easyoff HD, only a lot cheaper. I've used it quite a bit as a degreaser.

[stormin48061]

i bought about a pound of crystal drain opener at home depot for $3, called ro-tyme. don't know if its 100% NaOH, but gonna try that instead of easy off. I'm finding it difficult to see/control the removal of the anodizing with easy off and plus I don't know the concentration level in the easy off. Gonna go to the lab and get a little jar of nitric acid from my friend. Gotta remove the black paint from the paddles first, using spray air craft paint remover from Autozone. I tested an area, removes the black paint on the paddles with 2 applications. then it's buff time.

[Darkly-Noon]

Easy-Off Heavy Duty oven cleaner (yellow can) worked for me, but my results were not consistent. I bought a second-hand set of 16x8's, and did those first, followed by the original 16x7's that came with the car. I was only polishing the rims of the wheels, so I only sprayed oven cleaner there. It took 4-5 applications, leaving it on about 30 min - 1 hour, wiping and sanding the resulting grey sludge off, rinsing and repeating. Use the oven cleaner in a well-ventilated area and wear rubber gloves and a face mask.

For some reason I had a harder time with the 16x7's, and had to sand (hard) with 220 grit paper to get all the remaining anodizing off. If the surface looks a bit speckled, then all the anodizing is not off yet. Change your sandpaper often at this stage, as it dulls quickly. Once that was done, I moved on to 400, 1000, 1500 grit, then polish. I used Mothers mag and aluminum polish with the red foam polishing cone in my drill, and it worked well. Then I masked and sprayed Tremclad (Canadian version of Rustoleum) semi-gloss black.

It was a lot of work, but I am very happy with the results. It's not flawless, as I probably would have gone crazy trying to get a perfect mirror finish, plus it will eventually gain some scratches from normal driving and have to be re-polished. I like it - I think it compliments my particular paint colour well, better than the dull anodized finish did. Center caps are next...