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Salt and water etching Answered

I made an instructables about salt and water etching https://www.instructables.com/id/SALT-AND-WATER-E...

as I learned it in a jewelry class, so I never tough about been unsafe. I posted it as I tough it was a nice one to share, but I'm having some comment on how it should not be safe using stainless steel in this project. As I don't have absolute knowledge about this before, and I just report what I learned, I was wondering if that was correct or not. (I know sometimes people comment very random stuff). Anybody know something about this topic?



Somebody in your comments explained: stainless steel contains chromium, and some (many) chromium salts are toxic.

I read, but I tough stainless steel wouldn't get corroded very easily. In fact when I pull out the wire, after many uses, still look exactly the same to me as before ever using it. But maybe it does loose very little particles, and is not noticeable to see just by eyes...

"Not easily" is not the same as "not at all".

The concern seems to be from the photos in step 12. The sludge is mostly yellow-brown.

Copper-based chemicals tend to be shades of blue or green (https://en.wikipedia.org/wiki/Color_of_chemicals#S...), so people have assumed that the sludge is made of chromium salts from the stainless steel. However, chromium salts are strong shades of red, purple, bright orange and almost fluorescent yellow (https://en.wikipedia.org/wiki/Chromium#Compounds).

The chromium is more reactive than iron or nickel (stainless steel can be an alloy of all three), so will be the first yellow-brown colour is probably made up of iron salts (https://en.wikipedia.org/wiki/Iron(III)_chloride) ,with other contaminants from the tap water and the equipment.


Having said all that, you did the right thing to switch to recommending a safer electrode, just to eliminate as much risk as possible. You just need to go through the text again, because you still mention stainless steel in places.

Someone asked about this probably around a year ago here on the forums and I remember being surprised you can't use stainless steel, I think the answer was that using a carbon rod is the safest.

Thank you for answering, I will add it to the instructable