As a knifemaker, I like to etch my logo into my knives. I have a pretty fancy machine to do this, however others have asked about etching and marking so I came up with a fairly straight-forward device that one can make for around $20.
But first a little background. A lot of folks etch with DC power supplies and batteries. The current flows in a circuit through an electrolyte such as salt water. The etching process removes metal from the surface of the knife and makes valley where ever the Direct Current (DC) is allowed to flow. If we apply a little Alternating Current (AC) after we etch, we blacken the etched area. This is called marking.
So the secret to an etching and marking power supply is to have both DC (etching) and AC (marking) capabilities.
Before we proceed:
A little know-how is required to complete this project. You will needs some basic tools and a soldering iron.
Please be advised that the information provided is for educational purposes only. I will not be liable for use or misuse, damages, injuries or death resulting from this information. You must also be aware that the modifications shown here will render any product approvals e.g. UL/CSA invalid.
I originally published a long form of this build on my knifemaking blog: D.Comeau Custom Knives