Process of Anodizing Aluminum:
 
Aluminum naturally has tiny pores on its surface. Anodizing grows a thick,
hard oxide layer inside those pores to protect and harden the metal.

Basic Steps of the Anodizing Process:

1. Pre-Treatment (Cleaning):  Parts are cleaned to remove dirt, oil, and grease.

   • Alkaline cleaner tank + rinse

   • Acid cleaner tank + rinse

2.  Immersion & Electrolysis:  The cleaned aluminum is immersed in an acidic electrolyte bath (most commonly dilute sulfuric acid, and connected as the anode (positive electrode). A cathode (often Titanium or aluminum) is also in the tank.

3.   Oxide Formation:  Direct current is applied. Oxygen ions from the electrolyte migrate to the aluminum surface and react with aluminum       atoms to form aluminum oxide. Hydrogen gas evolves at the cathode.

4.  Sealing (final step):  The anodized part is typically rinsed and then sealed (hot waterand nickel acetate) to close the pores, dramatically improving corrosion resistance and locking in any dye.
    

Bowers Aluminum Common Anodize Types (per MIL-A-8625F)

• Type II, Class 1 → Clear (natural) anodize

• Type II, Class 2 → Dyed (colored) anodize - Stainlesss

Optional Finishes

• Bright Dip → Chemical polishing step before anodizing for a shiny, mirror-like clear finish
  Mechanical Buffing

• Black → Most popular dyed color