Thread: Home ‘bluing’

Originally Posted by SixtyTen

I have been doing a bit of reading into this and it seems a common modern rust blue solution is hydrogen peroxide saturated with salt.
You apply this liquid to the cleaned part, it causes red rust to appear very quickly, you rinse the part with water then boil in water for a few min. Remove, card off the black fluff and go again. Does anyone have any experience with a mix like this? Any idea as to the strength of hydrogen peroxide to use?

Depending on what you are bluing you may have an issue with hydrogen embrittlement doing hydrogen peroxide flash rust bluing on hardened or high stress metals. Won't hurt mild steels, but things like hardened parts or springs might become brittle. Just something to be aware of in relation to an otherwise excellent method for bluing parts.

A good basic video on the process, and mention of embrittlement



Somewhere in the depths of the internet is a video of a guy who caused embrittlement in flat springs to show what happens, but no idea where it is.