Here is my home brewed setup. It works quite well, though I haven't tested the AC/AC power supply yet. The etch pictured last was done prior to getting the AC/AC supply.
This is all the supplies needed. Most is self-explanatory, but you'll need heavily saturated salt water, cotton pads of some type, something to clean all the oils off the metal, and something to use as a resist.
The AC/DC power supply. My Granny-In-Law found it in the parking lot of the Costco she works at, I'm pretty sure it is from a laptop or maybe a printer, though I'm not sure. Laptop power supplies work good. The DC current will etch the metal.
The AC/AC power supply. I bought it off Amazon for $8.95 after shipping. The AC current will darken the etch.
The resists I used for the etch below, vinyl stick-on letters and electrical tape.
To etch, put the
positive clamp on the metal and the
negative on the pad. Soak the pad in the salt water and pat off the excess on a paper towel. Then blot the area to be etched evenly for 5 seconds and allow to cool for 5 seconds, until you reach the desired etch depth. Replace the pad and gently blot the etch with a clean paper towel to clean it, as needed. Be careful not to disturb the resist when blotting it clean.
Before removing the stencil/resist, gently clean the etched area and repeat the above procedure with the AC/AC power supply.
This is the resulting etch, after cleaning up the surface with a Scotchbrite pad. I etched extra deep on this piece.
If you don't have, or can't find, an AC/AC supply then you can darken the etch with cold bluing, vinegar, or other false patinas, and then carefully remove the excess from the surface by flat sanding it.
If you want a short lesson in reusing found materials/springs, then look carefully at the pictures where the power supplies are attached to the chisel. I made this chisel at my local blacksmith group's class. Everyone was praising it, so I decided to take it a step further and get some smart ass points. I put it to my grinder with a 400grit belt and polished it up. If I hadn't done that, I never would have seen the long, large crack running from about the middle of the piece to about a half an inch from the tip. I am certain the crack is a stress fracture due to it being from an old truck coil spring.
