I've tried some retail store cold bluing products on cold & hot rolled steel
parts, and have seen the sketchy results which weren't impressive.
I was looking for a cold method to darken a small stainless part (no idea
which alloy) and thought this video was very impressive.
First, I used silicon carbide abrasive to break up the straight/parallel
graining lines of the manufacturer's finish. This dulled the sparkle
I tried phosphoric to knock down the sparkle, but it didn't show much effect
after ~1/2 hour.
Then tried liquid Harris Stay Brite flux (zinc chloride and hydrochloric),
and it had little effect.
It now has a more weathered look which was about all I wanted.
The company selling the product has an 8oz size for ~$15, not sure about
where in the US they are, or how much shipping would be.
It appears to me that an 8oz bottle would blacken a lot of small parts. They
have a lot of other products for other metals and various results/colors.
9 years ago