Anodization (aka electroplating) a kind of hydrolysis that used to prevent long term corrosion on metal and make them scratch-resistant. also it's plated metal holds the paint better.
Usually it's an expensive process and hard to access necessary materials, but most metals such as aluminum & copper can be anodized with household items.
Step 1: Components
- distilled vinegar, rice vinegar works too
- cellphone charger (5v / 350~500ma)
- a nickel plated thing such as coin, wrench, key etc.
Step 2: Prepare Metal
First clean the material and remove the crust with sandpaper, that's removes the self-oxidated surface and increases the electrical conductivity
Step 3: Prepare Solution
fill electrolysis cup with the 1/4 vinegar, add salt and water
Step 4: Placement
connect positive probe to nickel plated element and negative to material to anodize. Vinegar leaves dark traces on edges that voltage doesn't reach, try to align center and use multiple positive probes if possible.
Step 5: Power On
observe the white bubbles around the material, if it's affects only one side, rotate the element on each 30 seconds. Also you need to do that in a well ventilated area due to poisonous gas output.
Keep the power on until anodizer completely dries out, remove the material and clean with a paper towel. it's important to remove dark scars while it's fresh.
Step 6: Results
you might not notice so big visual changes on first sight, try to scratch element. process is successful if material not easily getting damaged.