Pay attention! There is a pop quiz at the end...
Actually, this is just an FYI to file away in your memory banks. It has to do with the discussions I have read where two completely different processes are mentioned in regards to razors and knives. Those two entirely different things are etching and engraving.
Etching is a process where an image or lettering is "burned" in steel with the aid of both an ac and dc current via a series electrical circuit that sees through a prepared stencil. Stencils are made by transmitting light over an image that is printed on acetate and projects onto a special stencil material. After the stencil is "developed" in a solution it is then temporarily affixed on the steel where the image is desired.
First the etching machine is turned to a set value DC current. Two leads come from it and end at the steel with an alligator clip for ground and the other with a special pad holding an electrolyte solution to create the burn.
The lightly saturated absorbent pad is placed on the stencil for a few seconds at a time with light pressure. After 2 or 3 cycles, the machine is switched over to the AC current and the process is repeated. Simply put, the DC current gives depth to the image and the AC current turns the lettering or design black in color.
The first photos show the stencils, then the machine, and the leads attached to the pad that holds the electrolyte.