PLEASE NOTE: While this method of etching is safer than acid etching, it is still dangerous if you're not careful. There is a risk of poisoning and/or electrocuting yourself or others. Please make sure you are familiar with the entire process and have given plenty of thought towards how to do it safely before you try this yourself.
I learned about electrolytic etching from Steampunk Magazine (Issue 1) and the Steampunk Workshop. I followed their tutorials and examples, so I don't want to steal credit - I'm just sharing the process here because I've been asked to, and because I think it's neat and should be more widely known. If you're interested, I highly recommend you check out the tutes, examples, and discussions at SPM and SPW - they also give some other references on the process, as well as alternate ways to mask off your image, discussions of power supplies, all sorts of stuff that I will not be including here because that's not how I etched my trilobite. You can download Steampunk Magazine (or purchase hardcopies) here: http://www.steampunkmagazine.com/inside/downloads/.
You can find the Steampunk Workshop here: http://steampunkworkshop.com/.
What you will need:
-a laserjet printer
-inkjet glossy photo paper
-plastic kitchen scrubby, or steel wool
-a large-ish plastic tub, with a lid is even better
-at least two pieces of brass or copper (these will need to fit into your tub)
-two lengths of thick copper wire
-Root Kill (copper sulfate - POISON)
-something to stir with that you won't EVER use for anything else again
-a wallwart DC power adapter
-2 alligator clips (with colored ends is a bonus)
-possibly a multimeter
-an iron and ironing surface/board
-a rolling pin
-an old toothbrush or stiff brush
-black matte spraypaint
-a squeegee or a piece of cardboard (or something to act as a squeegee)
First things first, and I can't emphasize this enough - BE CAREFUL! You will be working with copper sulfate (Root Kill), which is a poison. You should probably wear gloves; you should DEFINITELY wash your hands often and well, and clean up any spills. I didn't wear gloves, but that was because I didn't know that copper sulfate is readily absorbed through the skin. Now I know, and next time I will be wearing some heavy-duty gloves, you better believe. You also don't want to ingest this stuff. It is gnarly, respect it. You are also going to be using electricity, and running it through exposed metal and water/electrolyte solution. Keep this in mind, and don't electrocute yourself. According to Steampunk Magazine, you *should* be okay if your power source is a wallwart, but I say no one wants to find out the hard way, right? So be careful. Put up your pets and small children. Don't touch your setup while it's plugged in. Make sure you've got enough space cleared for it, so you don't start a fire. Having a fire extinguisher around is a great idea. I got our fire extinguisher out and put it right near me. I also put our cats up, and made sure my husband knew what I was doing (in case I got hurt, and so he would know not to touch the setup and get shocked). I even made a sign for myself, to remind me when the electricity was on and not to touch anything until it was off. (For when I returned to it after letting it sit and etch for a while.) I'm not trying to scare you off of electrolytic etching, and I really didn't have any problems, but I don't want anyone getting hurt because of this tute, so be careful.
Prepare your image. You want to get a good, sharp black and white image, and you want to invert the colors (so it looks like a negative of the original), and then you want to flip the image across its vertical axis (so it's a mirror image of the original). Print that puppy up on a laserjet print but use inkjet glossy photo paper. This combination (inkjet glossy photo paper in a laserjet printer) makes the image transferable to your metal.
Now you need one of your metal pieces. I got my copper from http://kitkraft.biz/home.php, and it showed up in about a week. I also found some brass at my local Hungate's, but it ended up being too big to fit in my tub. I also tried using a brass outlet cover/wallplate I got at Lowe's - it didn't etch at all because it's nonconductive. (Which is good, since you put it over the outlets to prevent risk of shock. But for electrolytic etching, your metal needs to conduct.) Clean your piece of metal - I used rubbing alcohol and a plastic kitchen scrubby. Put your image facedown on your metal. Use your iron on its hottest setting to iron the paper on the metal. Two minutes ought to be good, and you want to press down hard with the iron, and stop every so often to run a rolling pin over the paper and metal. This is going to stink pretty bad, by the way. Mmm, burning paper. But you're melting the toner off of the paper and onto the metal. When you're done ironing, use some tongs or something to pick up the metal (it's going to be HOT) and drop it in a pan of hot water to start soaking the paper off. If you use glass, make sure it's pyrex, or can withstand high heat, just to be safe. Let the metal and paper sit in the water for about ten minutes, then start gently rubbing or peeling the paper off the metal. I found that the majority of the paper peeled right off, but the layers closer to the metal came off with rubbing (with my fingertips), or scrubbing with an old toothbrush. You might want to return the metal to the water to soften the paper up some more - I didn't have to do this, but it could help. Also, if you didn't melt all the toner onto the metal, and some of it comes off with the paper, don't despair. If your image is pretty much ruined, scrub the rest of the image off with steel wool and running water, and dry your metal and start over. I had to do this once, and I lived, so I think you will, too. (Although I did cuss a bit at first.) If your image isn't really ruined, finish removing the paper, and once it's all gone you can use acrylic paint to fill in any spots where there should be toner but you removed it. (You'll have to let the paint dry, of course, before you go to the next step.) Also, removing all the paper is key, so if you've got any delicate lines (that aren't filled in with toner), you might want to go over them with a pin or something, just to be sure. This is probably a good place to show you my first two attempts at etching, that didn't work:
On the right is that wallplate I've already mentioned. I've exposed the image and removed all the paper from where I wanted it to etch - the rest of the paper and the black paint is where I didn't particularly want it to etch, and the exposed brass around *that*, I thought might be neat etched, like a frame or something. Not so much, since it didn't etch at all. On the left is a copper round with an attempt at The Doctor's fob watch design. Looks pretty awesome, but unfortunately the paper wasn't completely removed, so it didn't etch evenly (or at all, in some places) where it should have etched. It's cool, though, I've got more pieces of copper, and I'm going to try again later.
You'll need to set up your etching tub. You'll need two pieces of thick copper wire to hang into the tub, to hold your pieces of metal. I got mine at Lowe's - they were in a cage near the electrical section, and you have to get an employee to get in the cage and cut your wire. (The cage is actually pretty awesome.) I got two lengths of 6 gauge copper wire, each cut to two feet. Here's how they looked after I bent them (and I just bent them with my bare hands, and I'm a weenie, strength-wise, so you can do it, too):
(Mine are green near the bottom because they've been in electrolyte for a while.)
Now you take your wallwart and your alligator clips. (I didn't know they were actually called "wallwarts" - if you're unfamiliar, too, they're those big adapter plugs that when you plug them in one socket, they cover the other one up, too.) You want your wallwart DC adapter to put out 3-4.5v. I used one my husband had and didn't need anymore, and it's a Sony adapter with a 4.5v DC output. Leave the end of the wallwart that plugs into a socket alone - you'll be plugging that into your power supply. Take the other end, and cut off whatever plug is there to plug into your appliance (that runs on DC and not AC, and hence needs the adapter). Separate the two cables, and strip each cable at the end to expose the wires. I think I stripped off about an inch. And there are wirecutting/stripping tools to help you with this, but I did it with a pair of scissors. (If you're trying to strip with the scissors, you want to cut through the cover but NOT the wires, so cut gently around, not all the way through, and then pull off the plastic.)
Here is where you MIGHT need a multimeter. You might not - there was a clever illustration on my wallwart that would have told me which cable was positive and which was negative, IF I'd noticed it. But I didn't, so I used a multimeter to figure it out. If you get a multimeter, make sure you get one that reads DC current - the first one I got didn't, so I had to go back and exchange it. Being careful not to shock yourself by touching the exposed wires, you're going to plug in your wallwart and use the multimeter to figure out which cable is positive and which is negative. Turn your multimeter on and set it to read DC current (there should be instructions included that tell you how to do this). Make sure the exposed wires aren't touching anything else, and plug in your wallwart. Touch one of your exposed wallwart wires to the red multimeter lead, and the other exposed wallwart wire to your black multimeter lead. If the multimeter reads a positive DC current, the red lead is touching your positive wallwart wire. (If it reads a negative current, you've got your leads crossed; switch them and check again, just to be sure.) Keep track of which cable is the positive one! Unplug your wallwart, and attach the alligator clips to the exposed wires. (This is where color-coded clips come in handy - you just slap the red one on the positive wire, and you'll always know which it is.)
Now you're ready to start mixing the electrolyte. Take your tub, and fill it up with water, leaving an inch or two at the top (in case of bubbling - which didn't happen for me, but I understand that it can). Add your Root Kill - start with maybe three tablespoons. You want to add little bits at a time, because if you add too much you'll have to throw it out and start all over. (See lower for disposal methods.) Once your Root Kill is dissolved in the water, hang your bent copper wires over parallel sides of the tub. Hook your positive alligator clip to one of the wires, and the negative alligator clip to the other. Remind yourself not to touch anything while electricity's running through it, and plug the wallwart in. Let it sit for about five or ten minutes, and then feel the back of the wallwart (the back of the actual plug part, not any of the metal parts) - it should be noticeably warm to the touch, but not really warm. Just warm enough that you notice it when you touch it. If it's really warm, your electrolyte is too strong, and you'll need to start over. If it's not warm, unplug it, add some more Root Kill, stir it until it dissolves, plug the wallwart back in, wait five or ten more minutes, check the back of the wallwart for warmth again. You basically do this until the wallwart gets warm. I ended up adding half the container of Root Kill, so it was pretty boring doing all that mixing, waiting, checking, mixing, waiting, checking, etc. But it would have been more annoying to mix it too strong and have to throw it out and start over, and I don't know what size tub you'll be using, so start small and if you need to add more, add more little by little. Here's my set-up while I was waiting for the wallwart to get warm:
We threw that spatula out earlier that day, because it was no longer good enough to use for food - so I dug it out of the trash to mix the electrolyte with. You also might see a teeny bit of the wallwart peeking out from behind my tub - that's because I was terrified of electrocuting myself, even just by pulling the wallwart out of the socket (plus the weight of the wallwart was pulling it out of that socket), so I plugged a surge protector into the wall socket, and plugged the wallwart into the surge protector. (Which is all sitting behind the tub in this picture.) This made it really easy to turn the electricity on and off - I just flipped the button on the surge protector. When I ran the etching overnight (when I was trying to etch that wallplate), I plugged a light into the surge protector, so that when the electricity was on, that light was on and shining right on the tub - so I had a very bright reminder the next morning that I should turn the power off before I touched anything.
Once your electrolyte is mixed, and your wallwart is just warm enough, you're finally ready to start etching! Make sure the power is off, then take your piece of metal with the image masked off on it, and put it on the bent copper wire that's connected to the positive alligator clip. Positive etches, negative plates - so whatever you want to etch into needs to be on the positive side. Lower the metal and copper wire holder into your electrolyte. Take another piece of metal and put it on the other copper wire holder - this piece of metal will be plated *onto*, with the bits of metal that are etched off of the positive piece. It's pretty neat. Once your pieces of metal are sitting on the copper wires, immersed in the electrolyte, you can plug in your wallwart, and the etching will begin. I shouldn't have to say it again, but I will: Don't touch anything while the power's on! The etching time will vary depending on your power source (wallwart) and the strength of your electrolyte solution (blue water). I let my etching attempts sit for about three hours before checking them, and then depending on how well they'd etch I'd decide how much longer to let them sit before I put them back in. (And of course, turn off/unplug the wallwart before you lift the plate out to check.)
Once your plate has etched enough to suit you, remove it from the tub and wash all that nasty poisonous electrolyte off it. At the same time, take your scrubby and remove the toner mask - you just want naked metal for the next part. You probably haven't used up the electrolyte solution, so if you want to save it for future etching, slap a lid on that puppy and put it somewhere safe, where no one will get into it by mistake, and it won't get knocked over and spilled. I even marked up the lid of my electrolyte, just in case someone happens to be poking around in the closet in my craft room, and comes across it. Although why anyone but me would be poking around in *that* closet by themselves, I have no idea. But, you know, safety first!
(I cleaned up the copper wires and my mixing spatula and wrapped them in newspaper, and they're stored in a box labelled "etching supplies" right next to the tub.) If you don't want to keep the electrolyte and etch more stuff later, you have two options. Now, you can just flush the stuff down the drain, since Root Kill is made to go down pipes and kill off any roots that are growing into your plumbing system. If you have a septic system, you don't want to do this because it'll screw up your septic system. The better method (endorsed by Steampunk Magazine, and the method I'll probably use once I've used up my electrolyte) is to add sodium carbonate (aka "washing soda") to the electrolyte and raise the pH to about 7 or 8. Then filter out the gunk at the bottom (metal particulates, by-products of the etching process) to take to your town dump's metal recycling. Then dump the rest of the liquid down the drain.
So now you've got an etched piece of brass or copper.
You could stop here, if you want, or you can get out the spraypaint. (Make sure you're spraying in a well-ventilated place. I like the outdoors.) Take your matte/flat black spraypaint and spray your metal. Then squeegee the black spraypaint off - it should stay behind in the etched cracks. (I did a couple spray-and-squeegees before I was satisfied with mine.) Let it dry.
If any spraypaint has left a haze or color on part of the metal where you *don't* want it, you can remove it with GooGone. (That's what I used, and it worked a treat. I also hear you can use WD40 to take spraypaint off.) If you use GooGone, you probably want to rinse your metal off before the next step, since you're going to spraypaint it again. (I don't know if residual GooGone would keep the spraypaint from adhering, but it seems like if GooGone will take spraypaint off, it'll also keep spraypaint from sticking in the first place.) Then coat your metal with the clear spraypaint, and let that dry.
Then I just used good old E6000 to stick that puppy on the front of a Moleskine, and let it sit a couple days to cure. Et voila! A Girl-Genius-inspired trilobite notebook.