Based on a couple requests from my latest scratch build, Behemoth, here is a basic primer on anodizing and etching aluminum. Why Anodize? Spray paint works just as well, right? Well not exactly. Anodizing embeds dye molecules in to the surface of your aluminum, whereas painting just coats the surface with a cheap pigment impregnated polymer. That means paint scratches, chips, and fades over time. Anodizing is permanent. The only way to take this stuff off is with concentrated NaOH. If that's not enough for you, anodizing maintains the exact same surface qualities of the original metal. Want a brushed finish? No problem. Want a high gloss sci-fi colored metal that doesn't exist in real life? Anodizing can do that. And c'mon, what's cooler than chemically treating your computer case with concentrated acid and a car battery charger? Anodizing Setup First thing is first, make sure your aluminum is SPOTLESS clean, and has the finish you want. You can't polish or shine this stuff after anodizing, and the process will dull the finish slightly. So always err on the side of higher gloss than you want in the end. Speaking of spotless, no fingerprints, grease marks, dust, scratches, etc. Use gloves. Polish up your aluminum, put on some gloves, and wash it with soap and water. Scrub it with a polymer brush (like a pot scrubber). Don't come anywhere near it with steel wool or a brillo pad though. Those tiny fibers of steel will embed themselves in the aluminum and completely ruin the anodizing process. It is absolutely critical to keep all other metals away from your aluminum. Also, once you scrub down your aluminum, keep it under water until you start anodizing. Aluminum forms a layer of oxidation on the surface VERY quickly, and keeping it submerged at after scrubbing makes sure you maximize the amount of available aluminum on the surface. You can anodize "any" aluminum, but 6000 series alloys are easy to find and work well. Many other alloy series have various levels of other metals in them which will screw up the anodizing. The quickest way to screw up your anodizing is to contaminate your acid bath. Once you get a tiny bit of another metal in it, forget it - you'll need to make up a new solution. Some aluminum alloys need to be de-smutted before anodizing (to remove other metals from the surface), and I still haven't found a great process for that. Luckily most aluminum you find at the hardware store, etc is a 6000 series alloy. Here was my first anodizing setup. It didn't work great, as the PSU doesn't put out enough amperage to drive the process. Also, the aluminum foil isn't the best material to use for a cathode as it can also have contaminants. But it did work, more or less. So this is all you really need for anodizing. A bit more advanced, but still quite easy and inexpensive. Here I have a rather large plastic tub (for anodizing large sheets), a car battery charger with 50 amp output (about $30 on Amazon), and a couple scrap strips of aluminum from the hardware store to use as cathodes. Note that I now have 2 cathode strips instead of just 1 - this helps balance the charge in the solution. A note on plastic tubs. The dimensions listed for the tub are usually the exterior dimensions at the top of the tub, which makes the number quite useless for determining whether or not you can submerge a sheet of metal in the bottom of the tub. Be sure to go to the store and measure before buying. And try to avoid anodizing anything larger than 9" across - finding tubs that big is a huge pain. One other thing to keep in mind, the last step of anodizing is to boil the part in water for 30min. You can also steam the part over a water bath, but this tends to leave streaks in the finish. So try to limit your part sizes to the largest scrap broiling pan you can find to stick in your oven.