How to Anodize a Finish

Anodizing a finish increases resistance to weather and corrosion. To anodize a finish, it is necessary to be extremely familiar with paint chemicals and the safety requirements when handling them. Anodizing works best with aluminum and does not work well with iron or steel. The texture of the surface changes when a metal undergoes anodization and the result is a smooth hard surface that is athletically pleasing.

Instructions

1

Clean the wrought alloys or cast alloys, using sodium hydroxide, ammonium bifluoride and sodium gluconate until each piece of alloy is thoroughly cleaned. This process removes debris, grease and dust particles so the anodizing will have a clean surface.

2

Grow the anodizing aluminum layer using direct current. An electrolytic solution is necessary to grow the anodizing layer. The current creates a buildup of aluminum oxide. Most voltages are between 15 to 21 volts, higher voltages are for thicker coats.

3

Dissolve aluminum oxide in an acid solution. The acid forms a coating of nanopores allowing the electrolyte solution to form on the aluminum substrate. The pores will also allow water and air to reach the substrate and can cause corrosion if the aluminum is not sealed.

4

Monitor electrolyte concentration, acidity, temperature and current. It is essential to monitor the various controls while doing an anodized finish. This process takes perfection and is extremely complex. Businesses that specialize in anodizing have spent years perfecting their skills. If performing anodization at home, it is necessary to continually monitor concentration, acidity, temperature and current while performing each of these steps.

5

Apply final acid coating. Using either chromic acid, sulfuric acid or organic acid, each alloy piece receives a final coating to anodize the finish. Chromic acid is one of the most popular types of acid and is sometimes called the Bengough-Stuart process, which is the type of anodizing coat airplanes and vehicles use.