Intro: Make Pictures With Acid Etching
Not quite as time consuming as writing in stone, but equally indelible: etch your own art in precious brass! The concept is pretty neat: circuit board etching acid eats away at copper and copper alloys. This means that it will eat away at brass, but it's mojo (technical term) is interrupted by the presence of iron. By adhering iron to a plate of brass by way of the iron oxide found in printer ink, we can etch any 2D pattern into our plate.
Step 1: Preparing the Plate
Start by meticulously cleaning your brass plate. Any size plate will do, and the acid bit to the tune of .003"/10min so you needn't worry about the thickness much. I cleaned mine with a Scotch Brite pad, and then wiped it off with acetone until my rag stopped pulling off dirt.
Step 2: Print, Place, and Iron Your Images.
This whole process requires high contrast printouts from a laser jet printer. I've been experimenting with different methods, and have found that transparencies get a really good resolution, but I believe that printing out on parchment paper would work even more smoothly. Anyway, the process is that after you print your image (greyscale just doesn't cut it, if you want a tonal range, use a halftone,) you lay the sheet print side down on your brass and iron it. I put my iron on its highest setting, with no water in it, and press on the image in patches. I press down fairly hard for about thirty seconds, and move up the image in this fashion until the whole image has been covered.
Step 3: Cool Off (and Soak)
If you don't have transparency paper the process will still work with regular printer paper (I just don't have the patience to do it right.) After letting the plate cool from ironing, you can soak it in a bath of warm water to loosen the paper away from the printed area now stuck to the brass. With gentle rubbing and a good long soak, most of the paper will come off, leaving you with a pretty clear pattern. I just said hang the wait and tore the damn thing off. I then carefully lifted the transparency away and Viola De Gamba!
Step 4: Take a Bath
I've used Jameco's powdered etching solution and it seems to work well, though, I believe that you could use any circuit board etchant. It is at its strongest when warm, and works fastest if you agitate the bath while it etches. I suggest you go to the hardware store and pick up some chemical-resistant gloves and a plastic bus tub as I've got here. This plate spent ten minutes in the tub and came out well, but I bet a longer soak would have done much better.
Step 5: Squeak and Clean
Remove the plate when you feel like it's done its job. It's best to experiment with a couple small test pieces before going for something large (and expensive.) After the etch is complete, scour the plate with a ScotchBrite and admire your work. You could use some black primer on the plate and buff it again to bring out the pattern in higher contrast. (Below, you'll notice both the etching shown in the tutorial, and an earlier test)
Step 6: Final Thoughts
Things I'll try for next time:
Longer exposure time with acid, as well as a method for heating and agitating the solution
Transfer from parchment paper
Etching for a massive amount of time to see what happens
While I'm here, I'd like to give some thanks to Michael Glancy, the super awesome electroforming ninja who suggested that I explore etching.