Sunday, February 1, 2009

The Neck Ringer - PCB layout / etch

I was pretty interested in creating my own PCB so I tried to find a project that I could see through from start to finish without too much frustration. I wanted to make an analog circuit and decided on an octave up/ring mod guitar pedal. I found a PCB layout for a Green Ringer clone on tonepad which is an incredible resource for this type of stuff.
I made a few modifications to the layout (namely the rad skull Zack made for a VHDL project) and printed to the backing of an Avery label sheet. I used the labels to fix the mirrored layout to the copper board and ironed it. It isn't an exact science, but after about 5 cycles of ironing and cleaning the board from botched transfers I've got a few pointers:

- Make sure you don't touch the backing or the copper board with your hands, the oil on either side will cause problems with the toner
- Print the layout to a regular sheet of paper and cut the backing to size. Place the piece directly over the layout using a label on the side you feed into the printer.
- If you do any touch-ups with a sharpie, give it a good time to dry before etching

As far as time, I had the best transfer after ironing the backing for 3 minutes, and letting it cool for 30 seconds before trying to peel it off. I warmed the bottle of etchant in a bucket of hot water, poured it into a plastic tray, and dropped the board in. I constantly agitated the solution by placing a pen under the tray and rocking it back in forth. It took 12 minutes for the copper to be completely removed, leaving this:



Yeah I know it's a sloppy soldering job, I was using an old Radio Shack iron with lead-free solder. It sticks like crazy.
I ordered a few sheets of Press & Peel, I'd like to see how it works compared to this method.

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