T&T: Rust stain removers

[Albin43SDtr]

'Lo All,

I hesitate to send this.... but......In another life, we often had 
the occasion to "permanently remove" rust from SS "stuff" bought by 
the Navy and other contractors and given to us ultimately for 
installation on Navy ships. The fancy name for this is passivation.

Our chemist gave me a small bottle of Nitric Acid - and a great 
number of warnings - and directions on how to swab the acid onto the 
SS. This supposedly removed any free iron, thus precluding rust. I do 
not know the concentration of the Nitric Acid, but I believe it was 
fairly strong.  After the brown stains disappeared, we neutralized 
the acid with baking soda and water. We never had any complaints from 
the Navy that I was made aware of.

I have also used Nitric acid on my own stuff and it worked well. 
Highly concentrated citric acid will also passivate SS, but I have 
never used it. It should be understood that the quality of the SS and 
any weldments bear directly upon the ability to permanently passivate 
the metal.

Nitric Acid is extremely NASTY stuff! Should you decide use it, be 
sure to scrupulously follow all safety precautions!!!! Not only the 
liquid, but the fumes are extremely dangerous!!!! Handling 
concentrated acid of any type is dangerous - DO NOT do it if you are 
not FULLY cognizant of the proper procedures! Google "Stainless Steel 
Passivation", and you should find many hours of reading about the 
subject. Also, be sure you are aware of the procedures - and follow 
them - for diluting acid: what you don't know can kill or permanently 
maim you or someone else! Soft tissue, such as eyes, nose and lungs 
are particularly vulnerable to acid and fumes.

Again, this stuff is not for "the casual user".

Take care and be safe.

Wayne
M/V Celestial
Albin43 Sundeck