Alodining / Alodizing

What is alodining?

Alodining is the chemical application of a protective chromate conversion coating on aluminum. The term Alodining has become a generic term for passivation conversion coating on aluminum materials, though in the strictest sense the term only refers to use of the specific Alodine product.

Benefits of alodining aluminum:

  1. It provides good corrosion protection un unpainted aluminum. It even protects when scratched. For example: alodined 2024 aluminum withstands salt spray 150-600 hours before forming white corrosion. Untreated 2024 corrodes in less than 24 hours.

  2. It provides an excellent electrically conductive surface. This helps to provide good electrical bonding in an airframe.

  3. Paint sticks to it extremely well. In some cases, it can substitute for primer.

Advantages of alodining compared to other coatings such as primer or anodizing:

  1. Adds no measurable weight.

  2. Does not alter the dimensions of parts (does not make holes smaller).

  3. Requires essentially no cleanup after application. Encourages treatment of all small parts as they are fabricated and installed.