Getting rid of salt residue, corrosion in regulator at home.

[Pearlman]

My rusty steel knife in almost mint condition after 15 mins in the ultrasonic cleaner with kitchen grade citric acid. I did not use phosphoric acid that I had because Google told me citric acid would deposit a “passivation layer” or coating on top of stainless steel. Needed about 5 mins of brushing and scraping - a “manicure” with a nail file to get last bit of rust stains off after removal from the ultrasonic.

Passivation with citric acid is an environmentally friendly alternative to nitric acid passivation, offering similar or improved results with less handling concerns. It works by removing free iron and other contaminants from the surface, allowing a protective chromium oxide layer to form, thus preventing rust

I forgot to take before pics but trust me I did a lot of window shopping for a new dive knife for almost a year because it was looking terrible with all the rust. Saved me about $70 or more easily … and then I was also reminded that cleaning up tools and stuff can be its own rewarding experience.

Question - Should I coat it with silicone grease or something to keep it rust-free?

 

[rsingler]

AFAIK, passivation takes 60°C, 25% citric acid and 30 min, and works only if all the rust is already gone.

 

[Geo7]

My rusty steel knife in almost mint condition after 15 mins in the ultrasonic cleaner with kitchen grade citric acid.

I have been using citric acid as well. Very gentle, and very clean...

 

[Pearlman]

AFAIK, passivation takes 60°C, 25% citric acid and 30 min, and works only if all the rust is already gone.

I didn’t know that! I did mine at 55C but only because the thermostat on my U/S cleaner seems to be broken (I had set it to 40C). Maybe I will do 30mins again today … good to know!

 

[tc]

I use about a half cup of vineger in my harbor freight 2 quart ultrasonic. (I'm cautious- have stripped a few finishes with higher mixes).

Simple green- again half cup to a couple quarts- if it smells of simple green it's probably too much.

Repair is a fine art, best of luck in your efforts!

 

[Frogman82]

I recently switched from citric acid powder to Lawrence factor wash, and the LFW does a better job in a shorter time.