Guide to Custom Anodizing

For architectural applications, SAF recommends AAMA 611-98 Voluntary Specification for Anodized Architectural Aluminum.

For other applications, the Aluminum Association has developed a system of aluminum finishing designations to ensure that your suppliers can identify and furnish the finish you specify.

Specific finishes of the various types are designated by a letter followed by a two-digit numeral. Each designation may be combined into a single composite designation to identify a sequence of operations covering all of the important steps leading to a final complex finish.

Almost all anodized finishes used on aluminum may be subdivided into three major categories: mechanical finishes, chemical finishes, coatings.

Descriptions of the most commonly utilized anodized finishes are as follows:

Mechanical Anodizing: (M)

M10 – Unspecified as fabricated
M22 – Specular-buffed
M32 – Medium satin – directionally textured

Chemical Anodizing: (C)

C12 – Inhibited chemical cleaned
C22 – Medium matte etch
C31 – Highly specular – bright dip
C32 – Diffuse bright dip

Anodic Coatings: (A)

Protective and Decorative (less than 0.4 mils thick)

A21 – Clear
A22 – Integral color
A23 – Impregnated color (absorbed dye)

Architectural Class II Anodizing (0.4 – 0.7 mils thick)

A31 – Clear
A32 – Integral Color
A33 – Impregnated color
A34 – Electrolytically deposited color (2-step)

Architectural Class I Anodizing (0.7 mils and thicker anodic coatings)

A41 – Clear
A42 – Integral color
A43 – Impregnated color
A44 – Electrolytically deposited color (2-step)

All designations are appropriate for non-architectural applications as well.

Composite designation examples:

Example 1: Aluminum Association (plus) Mechanical Finish (plus) Chemical Cleaning (plus) Chemical Etching (plus) Anodic Coating translates to: an Architectural Class II clear matte anodized finish designated as: AA-M10 C12 C22 A31.

Example 2: An Architectural Class I textured medium bronze electrolytic deposition (2-step) would be designated: AA-M32 C12 C22 A44.

Example 3: An Architectural Class I diffused bright electrolytic deposition and overdye (3-step) would be designated: AA-M10 C12 C32 A44/43.