Flower Etching - Feb 21, 2006

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Pocket Eno (aka fm3/budda machine) plays ambient loops and makes long hours in the lab possible. The copper sheet (on left) comes in rolls and cuts better with scissors than shears or snips. Part layout laser printed on glossy paper. One sheet is used on each side of the copper clad board and the Xs are used to register the sheets to each other. Closeup of part layout. The sheets are aligned by aligning the Xs while looking through the sheets at a bright light, then taped together with masking tape. When printing, I offset the pattern on one sheet so I could keep the masking tape flat on the longer edge. The copper sheet is sandwiched between the two printouts. A clothes iron is used to fuse the toner to the sheet. I press with the tip of the iron to ensure the pattern transfers. The sandwich is soaked in hot water and the paper is carefully peeled away. A toothbrush is used to remove the remaining paper. The toner stays on the board. Boards free of paper! In between the toner traces there's usually some almost-transparent paper that needs to be scrubbed. At this point you should check for any dropouts in the pattern where the toner didn't transfer properly or fell off. Dropouts can be fixed using a Sharpie (red apparently works best). On one of the patterns, I also drew in "sprues" to hold the pieces together. The excess copper was trimmed away and they're ready for etching. The stir sticks kind of help to keep the pieces separated and off the bottom, but a better solution is needed. The white tray is filled with hot water in an attempt to speed the etching. Parts being etched in ferric chloride solution. This stuff stains, and you can't use metal utensils for obvious reasons. Mmmm, soupy. Etched parts ready for cleaning. The pieces on the right stayed together because I drew in connecting traces with the Sharpie. I tried cleaning the pieces with nail polish remover (acetone) but they are pretty stubborn. Then I used laquer thinner (thanks Jeff!) and the toner came right off in that efficient but highly toxic kind of way. Ready for solderinig. Pretty blue surface mount LEDs. Soldering to the copper was hard because the metal kept sucking away the heat. Making smaller tabs to solder to would definitely help. Flower shaped and supporting wires/stalk added. Todd's creation for Living Art. A sequence of panels illuminated using the Fibonacci sequence. The panels were originally laptop backlights.