Anodizing Polished Aluminum

[LodiWino]

George Anderson made a set of billet polished aluminum valve covers for my FE motor. I had them clear anodized and they came back a mat finish.

What needs to be done to restore the beautiful polish job?

[FWB]

anodizing does that, the process is an acid based wash. it creates porosity in the surface, which removed the polished surface treatment. to go back to the previous look they will need to be striped chemically, at the anodizer, repolished and then i would clearcoat.

Fred

[David Biele]

It also depends on how they sealed the anodize. Hot water or sodium dicromate. But the bottom line they will never look like virgin polished alum.

[MFE III]

I had my polished engine bay alum panels anodized thinking it would preotect the polished finish. They came out greyish with a matte finish. Had them stripped and repolished.

[bobcowan]

Anodizing hardens the surface and dye's it. The color becomes part of the alum. It's not a coating like paint. Stripping it off means removing material.

Anodized alum can still be stained by gas and some oils. Not nearly as much as raw alum, but it can still be stained.

You could probably get much of the shine back by having it powdercoated in high gloss. It will get most of the shine back, thouroughly seal the surface, and retain the color you want. Plus, it can be done in a few hours for just a few dollars (compared to re-polishing).

[David Biele]

Stripping the anodize on valve covers will not be a problem at all. It only will remove a few tenths of material.