When you feel like doing some really rapid prototyping and don't want to wait around for a board to come in the mail, you usually have to print a board of your own.  I've done this a number of times (the original bullet counter was a home-printed board).

The whole process has a number of steps (which I will be going into in another post), but one of them involves printing an acid-resistant substance on a copper sheet and dissolving the un-coated copper in an acid.  As I have mentioned earlier, I had some really crummy ferric chloride acid that didn't do a very good job of etching my boards.  I would usually end up sitting around for an hour or so waiting for it to etch only to have the etchant start to eat under my etch-resist while other free portions were still un-dissolved.

Ferric chloride is also kind of pricey, so I decided to try my hand at some home-brew etchant.  I found a recipe online that calls for just two ingredients:

Muriatic Acid (HCL) and Hydrogen Peroxide (H2O2)

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