This post documents another attempt to mark my reels. Here I have used an electrochemical etch kit from Lectroetch. They promote its use to knifemakers, where the blades are typically steel.
The kit consists of a low voltage AC transformer with pad and alligator clip electrodes, bottles of etching electrolyte and neutralizer, and some stencil material.
The stencil material is a laminate of permeable and impermeable layers. The impermeable layer can be rubbed away with a stylus. It can also be removed using a mechanical typewriter (remember those?). Below are stencils that Lectroetch made for me.
After etching with the wetted electrode pad, I had a black image. But when I wiped it with the neutralizer, most of the black oxide came away.
I sent a nickel silver sample to Lectroetch, and they confirmed that the oxide does not adhere on this material. So it looks as if I can get an untinted etch, if I can figure out a way to remove the rest of the oxide without defacing the image.
I later tried etching some 303 stainless, and the black oxide adhered.
One problem with the etch on both nickel silver and on stainless is that it is quite shallow. The logo is quickly obscured by a little sanding at 1200 grit. I think that the engraving done by a jeweler, even by diamond point drag, is more durable.