Anodic Coating Designations

Anodizing Specification HelpALUMINUM ASSOCIATION Anodic Coating Designations

To help with anodizing specifications, the chemical finishes and comparative anodic coatings chart below features guidelines that match processing and required anodic film thickness with customer needs.

Mechanical Finishes

Mechanical finishes are less common than they once were because are labor intensive and difficult to apply. Most aluminum specifications come with a generic  “M10” which means “Unspecified, As Fabricated.” However, some applications call for specular buffing (M22) or directional sanding (M32). Contact SAF for more information about brushed, buffed and polished finishes, and other Anodizing Specification information.

Chemical Finishes

Type of Finish Alcoa Designation Alum. Assn. Designations Description Examples of methods of finishes (Not Definitive Techniques)
Non
Etched
Cleaned
C-10
C-11
C-12
C-1X
Unspecified
Degreased
Inhibited
Chemical
Cleaned
Other
Organic solvent treated
Inhibited chemical type
Cleaner used
To be specified
Etched R1
R2
R3
C-20
C-21C-22
C-23
C2X
Unspecified Fine Matte
Medium Matte
Course Matte
Other
Trisodium phosphate, 3-6 oz / gal. used at 140-160 deg F for 5 min.
Sodium hydroxide, 4-6 of. / gal. used at 140-160 deg F for 5 min.
Sodium Fluoride. 1 1/2 oz. plus sodium hydroxide, 4-6 oz. / gal. used at 140-160 deg F for 5 min.
To be specified
Brightened R5-Bright Dip*
EB10, EB30
Bright Dip
C-30
C-31
C-32
C3X
Unspecified
Highly Specular
Diffuse bright
Other
Chemical bright dip solution of the proprietary phosphoric nitric acid type used or proprietary electro-brightening
Etched finish C22 followed by brightened finish C31
To be specified

*Trade Name of Aluminum Company of America (Alcoa)

Comparative Anodic Coating Designation

Film

Thickness

Alcoa

Designation

Aluminum

Association

Designations

Descriptions Type of

Finish

Film

Thickness

0.0001″ Alumilite 200
.00015 minimum film thickness
A21 Clear

(natural)

Coating

Protective and decorative

(coatings less than 0.4 mils thick)

Thickness to be specified

by customer)

2.56 uM
0.0001″ n/a A22 Coating with intergal color (discontinued by SAF) 2.56 uM
0.0001″ n/a A23 Coating with impregnated color. 2.56 uM
0.0001″ n/a A24 Coating with electrolytically deposited color. 2.56 uM
0.0002″ Alumilite 201 .0002 minimum film thickness A212 Clear

(natural)

coating

5.13 uM
0.0003″ Alumilite 202 .0003 minimum film thickness A213 7.69 uM
0.00036″ Alumilite 203 .00036 minimum film thickness A213 9.23 uM
0.0004″ Alumilite 204 .0004 minimum film thickness A31 Clear (natural) coating Architectural Class II 10 to 18 uM (.4 mil to 0.7 mil) coating thickness. 10.26 uM
0.0004″ n/a A32 Coating with

integral color (discontinued by SAF)

10.26 uM
0.0004″ n/a A33 Coating with

impregnated color

10.26 uM
0.0004″ n/a A34 Coating with electrolytically deposited color. 10.26 uM
0.0007″ Alumilite 215

.0007″ minimum

film thickness

A41 Clear

(natural)

coating

Architectural Class I

18uM (0.7 mils) and greater

anodic coating.

18.0 uM
0.0007″ Duranodic (311, 312, 313, 335) (discontinued by SAF) A42 Shades of bronze & black 18.0 uM
0.0007″ Dyes A43 Nearly unlimited

color selection.

18.0 uM
0.0007″ 2-Step A44 Shades of bronze & black 18.0 uM