All fonts are in my computer. The top and bottom two pictures are electro-etched. This outfit
http://www.img-electromark.com/ takes my artwork and makes what's basically a silk screen.
When I get the screen (stencil) I position it on the part I want to etch with a strip of duct tape and hook up my power supply. I use a home car battery charger set on trickle which is about 2 amps.
Positive lead goes to the work piece and the negative connects to a "wand" I've made. The "wand" is nothing more than a strip of old t-shirt, rubber-banded to a piece of scrap metal so the t-shirt face is larger than the area of the stencil.
Next mix up a batch of electrolyte which is tap water with some salt added and if I'm etching steel, a pinch of ferrous sulfate (available at chemical supply houses or some garden shops as a soil additive).
If I'm etching copper based alloys like brass of bronze, a pinch of copper sulfate (same sources; copper sulfate is the active ingredient in sewer line root killers).
When ready to go, remember to wear gloves-- we are playing with electricity here. Dip the cloth face of the wand in electrolyte and dab off the excess (you want the cloth face to be wet but not dripping) and apply to the stencil. The current flow is only through the openings in the screen mesh and so that's where the etching happens.
Refinements are; using a strip of duct tape to hold the stencil will act like a hinge so you can check your progress and the stencil will return directly over the area you're etching as you continue on.
When the cloth begins to turn black, it's getting full of sludge so swapping it out for a clean piece or area will keep you etching.
My ferrous sulfate or copper sulfate additives are to make the electrolyte more efficient. Without going way off track; this is basically plating process in reverse. When you apply current, an iron or copper molecule doesn't jump off the work piece and swim across to the negative side of the pool. It jumps off the work piece and a molecule of iron or copper dog-paddling around the negative side decides the pool's getting crowded and jumps out.
My power supply set-up is what I have handy but I've done small areas like logos with nothing more than a 9vdc transistor radio battery and a Q-Tip.
Your stencil can be rinsed and pat dried and reused if you take care of it. Sludge clogs the screen mesh but what's hardest on it is heat. If you apply continuous power, the current flow will create heat and that'll break down the screen.
I usually apply power with a rocking motion of the wand across the stencil for 20 seconds or so then back off for about the same amount of time. Repeatedly re-dipping the cloth face in electrolyte will also have a cooling effect.
I check my progress and stop when I'm satisfied with the depth of etch. This isn't a fast process with arcing and large volumes of steam so I'm able to take my time.
The beauty of this process is; A. as soon as you pull the wand away, the etching stops so there's nothing to have to neutralize. And B. No nasty super fund site chemical clean up. Pour the copper sulfate stuff down the sewer to keep tree roots at bay and the iron sulfate into your soil as a conditioner.
The breach casing for my Gatling gun is done chemically. I have an outfit that makes vinyl banners and they cut out my artwork but when "weeding" we discard the lettering and keep the background. Here it gets a little tricky because most plotters require "vector artwork" so that the cutter just sees shapes, not type fonts. This conversion is just choosing what file extension you want to export the artwork out of your computer and into a flash drive or a file you can email.
Chemical etching is a little trickier in that you have to be sure to keep the etchant off anywhere you don't want etched. I use ferric chloride which is the same stuff they use to etch printed circuit boards. It eats the copper in copper alloys and if I accidentally get a drop or two on the brass, I can't possibly wipe it up fast enough to keep from staining.
Ferric chloride is NOT something you want to pour down the drain. The good thing is that you can keep reusing for future etching jobs. It's kinda strange stuff in that the concentrate isn't as active as the diluted version. "It isn't acidic but acts like an acid in the presence of water" is how it was explained to me.
With this stuff you definitely want a good pair of chemical gloves because it stains permanently, like a USDA beef tattoo. Trying to wash it off with water just makes it more active.
When the etching job is done, I neutralize the stuff with a thick solution of baking soda and a good scrub brush. After thoroughly scrubbing down the etched area and rinsing it off, I put the part away with a layer of baking powder.
If I'm doing a lot of fine line detail, I keep a close eye on the vinyl mask. Once the etchant starts to work, it eats in all directions, not just straight down. So once the vinyl has started to lift is where I stop.
