Electroplating is usually done in factories for things like covering car bumpers in chrome, but the process is simple. An electric current runs through an object submerged in a chemical bath along with a strip of metal called the anode. The current rips electrons from the material of the anode, turning it slowly into metal ions. The ions travel through the bath and regain electrons at the surface of the object, where they turn back into solid metal. The net effect is to coat the object with metal taken from the anode: a shiny finish in two or three minutes.
But if the solution isn´t just right, or the surface not correctly prepared, the thin layer of metal won´t stick. Fortunately, today you can buy plating solutions that work well out of the bottle, and unlike in the past, most aren´t cyanide-based.
I created my design using a custom rubber stamp ($12.50 at a laser-cutting shop) to apply ink to the back of the iPod. The ink blocks the current, leaving an outline of my pattern. To avoid dunking my new iPod in a chemical bath, I temporarily glued a bottomless miniature tank onto its back.
It took about 10 tries, but I finally got the plating to stick even while I scrubbed the ink off with acetone. Apple products may not be perfect, but with some sandpaper, glue, lasers, industrial chemicals and two AA batteries, you can fix them.
Copper-Plating an iPod
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1. Sand the back of the iPod with 400- and 600-grit sandpaper.
2. Apply a pattern with a stamp [right], or hand-draw it with an etch-resist pen.
3. Bathe the back in plating solution (available at fdjtool.com or epi.com).
4. Place the copper anode partially in the solution.
5. Attach a battery supplying one to three volts at 0.1 amp-positive end to the anode, negative to the object. Let it all sit for two minutes.
6. Clean off the ink with solvent. If the plating doesn´t stick, just sand off your mistake and start over.
ACHTUNG! Always be careful around electricity. Don´t drink the blue liquid. Children should not try this project unsupervised.
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Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.