Guide to Anodic Coating Designations

Aluminum Association Anodic Coating Designations

The chemical finishes and comparative anodic coatings chart provides guidelines that match processing and required anodic film thickness with customer needs.

Mechanical Finishes for Aluminum

Mechanical finishes are less common than they once were because they are labor intensive and difficult to apply.

Most aluminum is specified with “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 aluminum finishes.

Chemical Finishes for Aluminum

Type of Finish	Alcoa Designation	Aluminum Association Designations	Description	Example 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 MatteMedium 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 electrobrightening 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