What is an alkaline etch?

Etching aluminum in sodium hydroxide is by far the most common pretreatment for aluminum that is to be anodized. Alkaline etches are also used to strip off anodic coatings prior to painting. However, under no circumstances should an etch-only finish be used in a finish product because there is no way to prevent the rapid onset of corrosion. An etch-only finish normally is regarded as an unsightly mess by our customers. It must be anodized or painted immediately after etching to protect the metal.

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