Etchant for Stainless Steel

A. Danny,

You might try ferric chloride [on eBay or Amazon] (FeCl3) solution with a free acid (HCl) content of 1% or so. What do you use for copper?

Bobby

Q. I tried a ferric chloride[on eBay or Amazon]and HCl solution and it seemed no better than HCl itself for stainless. It is very, very slow and would take weeks to cut through.

On the other hand, I tried running a current through the plate to another electrode and voila! The rate is quite acceptable. However, this does necessitate a more complicated setup, constant cleaning of the other electrode, and the sheet will need conductive "wires" left in the pattern if it's being milled, so the parts must be cut out. My greatest concern is the oxygen bubbles gradually lifting the resist away at the edges. I imagine keeping the current density down to a point where the oxygen is still soluble would fix that. I'm capable of dealing with these complications but I wish I just had an electroless mordant.

I'm going to have to check and see if it works with raw HCl, as it's much cheaper than ferric chloride[on eBay or Amazon]+ HCl.

A. Weeks? What in the world are you etching?

In your electrochemical cell, you have the stainless connected as the anode? If you are anodizing in HCl, you are probably reducing hydrogen gas, not oxygen, at the cathode.

What do you use to etch copper?

Bobby

A. Murthy,

I do not know how to do Sharpening by etching. We use electropolishing, particularly the universal electrolyte, especially its modification for sharpening.