Survey the surface characteristics of the aluminum. If it has surface dirt and grime, clean it with soap and water prior to anodizing. If it has paint, you need to remove the paint with sandpaper before anodizing. Finally, if the aluminum has been anodized before, you need to treat it for a few hours in a solution that can strip off the anodized coating.
Make a bath of 1 tablespoon of lye in 1 gallon of water. Immerse the aluminum in the bath for several minutes. The bath will thoroughly clean the surface of the aluminum.
Pour the battery acid into the ceramic tub. Plug in the battery charger and connect the platinum sheet to the cathode of the charger. Connect your aluminum to the anode. Immerse both the platinum sheet and the aluminum in the acid.
Drop the stir bar into the ceramic tub, and place the ceramic tub on the magnetic stir plate. The stir plate will ensure equal distribution of the metal oxides on the surface of the aluminum.
Increase the voltage rating of the charger to 10 amps. Leave the aluminum in the bath for about two hours, until its surface is slightly yellow.
Use tongs to remove the aluminum from the bath. Rinse it thoroughly in distilled water.
Prepare the dye solution per the manufacturer's suggestions. Immerse the aluminum in the dye solution and leave it in for the recommended time.
Remove the aluminum from the dye solution with tongs and rinse it with room-temperature distilled water.