Custom Anodizing – How to Specify
For Architectural applications, SAF recommends specifying AAMA 611-98 Voluntary Specification For Anodized Architectural Aluminum. For other applications, the Aluminum Association has developed a system of aluminum finishing designations to assure 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 improtant steps leading to a final complex finish.
Almost all anodized finishes used on aluminum may be subdivided into three major catagories: 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.