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Anodizing 7075 Aluminum

Don Kress

Anodized 7075 aluminum is one of the toughest forms of aluminum available. By removing aluminum oxide from 7075 aluminum and creating a porous surface to which any of a number of hard coatings can be applied, you make the aluminum not only much stronger, but also resistant to practically all types of corrosion.

Anodized 7075 aluminum is lightweight and as strong as steel.

In addition, anodized 7075 aluminum is more resistant to scratches than standard 7075 aluminum.

  1. Heat the sodium hydroxide until it is approximately 120 degrees Fahrenheit, and then bathe the 7075 aluminum in the sodium hydroxide. This will remove any surface impurities that may exist on the aluminum and leave it clean for the anodizing process.

  2. Heat the sulfuric acid to a temperature of between 68 and 70 degrees Fahrenheit, or approximately room temperature. This may not be necessary depending on the ambient temperature of your work station. If, for instance, the room temperature is 72 degrees, then the acid will be the correct temperature. Use only glass containers when using sulfuric acid, and wear nitrile gloves whenever working with the acid to prevent acid burns on your hands from spilled liquid.

  3. Insert one of the electrical leads from the 12-volt charger into one side of the sulfuric acid, and then the other on the opposite side. The aluminum will rest directly between these two leads.

  4. Place the aluminum into the sulfuric acid bath with the pliers so that it is completely submerged, and then turn on the power to the charger. Leave the aluminum to rest in this state for approximately two hours. Be careful when placing the aluminum into the bath that you don't splash any acid on your clothes.

  5. Boil a container of water into which the aluminum part can be fully submerged after being removed from the sulfuric acid bath. While the water is boiling, turn off the power to the charger, and then remove the aluminum from the sulfuric acid. Rinse the part with boiling water to wash away any remaining sulfuric acid as well as to halt the oxidation process. Allow the 7075 aluminum to dry before using it for its intended purpose.


Sulfuric acid is extremely caustic and can cause severe chemical burns. If you get sulfuric acid on your skin or clothing, immediately rinse the affected area with water, holding it under running water for approximately 20 to 30 minutes. Remove clothing to which the acid has come into contact while rinsing the area with water, and then discard the article of clothing. Serious chemical burns should be treated at an emergency care facility.