Aluminum, like Stainless Steel, is corrosion resistant. It is, however, much lighter and softer than Stainless and Carbon Steel. To prevent the dull appearance that results from the oxidation of the outer layer, Aluminum can be either clear or color anodized after perforating. Unlike paint or powder coating, anodize film is built from the aluminum itself and takes on a translucent appearance. The alloys listed below are categorized into two types, non-heat-treatable and heat-treatable.

Carbon Steel is the most corrosive and therefore, the least expensive of the three most commonly perforated metals. Produced into coil form by roller leveling to a desired thickness either once while the steel is still hot or again after it has cooled, each of the Carbon Steel types listed below are referred to as either Hot Rolled or Cold Rolled (ex. Cold Rolled Commercial Steel). The difference in processes result in products that differ in terms of cost, quality, and mechanical properties. In short, Hot Rolled is typically less expensive and produced in thicker gauges 7-16, whereas, Cold Rolled provides tighter tolerances, better surface finishes, and while it can be produced in practically any gauge, it is most readily available in thinner gauges 14-28.

Stainless Steel, unlike carbon steel, is corrosion resistant. It contains chromium which, when exposed to oxygen, creates an invisible protective film. Stainless steel types are classified into three different groups based on their ability to be hardened. Austenitic stainless steels, which can be hardened by cold working, meet a wide range of design criteria. They are essentially non-magnetic, although they may become slightly magnetic due to cold working. Martensitic stainless steels are straight-chromium types that can be hardened by heat treatment. They are magnetic. Ferritic stainless steels, like Martensitic stainless steels, are straight-chromium types and they are magnetic. Ferric stainless steel, however, cannot be hardened by heat treating and only moderately hardened by cold working.