"DeepDiver" wrote in message
...
"Harold and Susan Vordos" wrote in message
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The harsh reality is that all 300 series stainless has the potential
to rusts to some degree unless it has been passivated. One of the
certified MIL processes is to soak the material in a heated solution
of nitric acid, distilled water and potassium (di)chromate for a
given period of time, which removes the free iron.


Is this passivating process something that could easily be done in a home
shop?

- Michael

It is, but you'd likely have a hard time buying the nitric acid and the
potassium dichromate. Chemicals are quite difficult to buy now, and even
more difficult to dispose of. It was simple when I did it way back in the
mid 70's. It was by rude awakening that I realized that what I was doing
was passivating when I processed some components for an aerial surveillance
camera developing unit many years ago (I still have some of the extra
components as a memento of the job).

Needless to say, this was a defense job, which normally would have specified
a MIL spec with reference to passivation. Instead, the print had specific
requirements for the parts to be processed as I had mentioned in my previous
post. I dutifully did exactly as the print specified, giving no thought to
what I was doing. It was well after the fact that I realized that I had
passivated the parts, nothing more. My biggest regret was not having made
an exact record of the components and process. I could have used in on
many occasions.

For me, it was no chore to do the process, because at that time I was
refining gold as a hobby, so I had a fume hood and all the necessary
chemicals at hand to do the job. Handling nitric acid can be
challenging. It is quite hard on flesh.

Harold