What Is Clear Anodizing?

Clear anodizing is a way to anodize metal that produces a clear finish, and it is one of the more common anodizing methods. It is done by placing the metal in a powerful acid, usually sulfuric acid, and then quickly immersing the metal into hot water to seal the oxide layer. This commonly is done to aluminum to create parts for cars and trucks, printing plates and miscellaneous parts. While clear anodizing also can be dyed, this must be done quickly and right after the acid bath. The disadvantage of this method is that the oxide layer is not as strong as other methods, so this metal can rarely be used for building or engineering.

The method for clear anodizing is one of the simpler and easier ones to do. Aluminum or another metal is placed in an acidic electrolyte; this usually is from sulfuric acid. An electrode then causes the acid to lose its oxygen molecules, which are adopted by the metal. This adds a new layer to the clear anodized metal. After the acid bath is finished, the metal is quickly dipped in hot water to seal the layer and make it permanent.

This is most often done with aluminum, because it is a versatile metal that easily interacts with oxygen and it can be made into many parts. The most common parts for clear anodizing include car and truck parts, printing plates and other miscellaneous parts, such as those for telescopes and some metal hangers. With clear anodizing, the metal becomes resistant to wear and liquid does not rust or affect the metal in any way.

After anodizing, metal is capable of taking on a dye solution and changing color. While the metal used in clear anodizing must be quickly submerged in hot water after the acid bath, one can dip it into a dye solution before dipping it in the water so it changes color. If one takes too much time, then there may be problems with the permanence of the oxide layer.

While clear anodizing is popular and used for many things, it does have one disadvantage. The water temperature and the method in which the metal is anodized mean the oxide layer is not as strong as with other anodizing techniques. For this reason, the metal is rarely strong enough for building or engineering needs. To make it stronger, cold water and harsher acids can be used, but these constitute different anodizing methods.