Hey, all. I thought I'd share a little tutorial on how to cheaply etch your blade, tools, etc. on the cheap without getting cheap results.
1) A 6-12 volt lantern battery (such as a PP9 9 volt)
2) 2 alligator clip leads
3) Small plastic container of water
4) Table salt
5) Cotton ball or Q-tips
6) Stencil material or other resist (see below for details)
Your first task is to create a stencil/resist that will allow only the steel you wish to etch to remain exposed. One simple way is to use self-adhesive stencil paper (Hobby Lobby). It's reusable and is fairly durable. Or, you can use thick packing tape or fingernail polish (a little scary and not really recommended, but it does work and can be removed easily with acetone). Alternately, some printing and copy companies can print stencils on vinyl. You simply submit a digital version of you mark and then request a NEGATIVE stencil.
Regardless, apply the resist to the surface you're going to etch and make sure it's attached VERY well! Although I didn't do it on this tutorial, I usually tape the rest of the blade off for safety's sake.
Using a needle, engraver, Dremel, or woodburner (if using vinyl or tape), create your mark through the resist. If using an adhesive resist, you can do this on another surface and then transfer the resist to the blade. Here's my example, a decorative version of my initials, CRI:
Now, mix up a solution of warm saltwater. I usually add salt until it no longer dissolves.
Next, connect one end of the positive alligator clip to the positive post on the battery, and the other to the blade. Be careful not to scratch the surface if you've polished it to a high grit. In this example I'm using a nearly-completed knife (no finish or edge yet), but it's safest to connect the positive lead to the tang of an unfinished knife to avoid scratching.
Then, take a small bit of cotton ball or a Q-tip, put it in the jaws of the negative alligator clip, and dip it in the saltwater. Squeeze most of the excess out. (Note: the metal of the clip must come into contact with the water on the cotton ball/Q-tip.)
Connect the negative lead to the negative terminal on the battery and then begin dabbing the area to be etched. The cotton ball will "fizz" if all is connected properly. Here's what it would look like at first:
The black in the etch and on the cotton ball is the metal being removed. You may have to replace the cotton when it begins to look like this:
Periodically dab the etch with a clean rag to removed excess water and metal. When sufficiently etched (your preference), remove the stencil. It will probably look pretty ugly at first:
A little cleaning will reveal your etch:
That's it! Hope it helps.