Okay, so I have some pictures from when I remade the shift register breakout boards to control my 16 outlets. I just hooked them up for the first time and they are working quite well. I'm currently working on a basic sketch to make sure they work well before I integrate it into my main projects code.
This time I used about 2 cups of almost boiling water, 1/2 cup of HCL (Muriatic acid) and about a cup of common 3% H2O2 (Hydrogen Peroxide). It took about 30 minutes to fully etch this time which I attribute to the dilution the hot water.
The boards were drawn with a Faber-Castell Art marker.
Here are the boards right after being put into the solution.
10 Minutes,
20 Minutes,
30 Minutes later with the maker removed using standard acetone nail polish remover,
Here are the boards after drilling the holes, soldering, and covering the tracks with clear nail polish to prevent oxidation.
The holes aren't very straight as I just used a 1/16 in drill bit and a standard drill. A drill press would make things a lot easier as I had to tap each hole beforehand with a nail to keep the bit from slipping around.
Here is the board hooked up to the arduino and the sainsmart 8-channel relay module.