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How to strip hard chrome at home

adv.

Q. Having a hard time stripping hard chrome off some brake caliper pistons. Original chrome is peeling and badly pitted.

Tried HCl and didn't touch the chrome (but turned exposed base steel black). Then tried NaOH, sitting for 3 days with zero effect.

I'm ready to try anodic cleaning in NaOH but not sure what to do with the hexavalent chromium.

Andy Somo [last name deleted by Editor]
- Bloomington Indiana
October 8, 2023

It's a piston from a brake caliper. These are normally zinc, however one caliper looks like it was rebuilt before and looks like a thick layer of hard chrome. This is partially corroded where the seal was, as it sat for several decades.

I'm assuming it's hard chrome, as I can't really think of what else it could be.

The pistons in the other calipers were zinc and dissolved easily in 35% HCl. But the HCl would not touch the hard chrome.

Andy Somo [returning]
- Bloomington Indiana
October 17, 2023