ASTM D1730

ASTM D1730 – Standard Practices for Preparation of Aluminum and Aluminum-Alloy Surfaces for Painting

Description:

Abstract

These practices cover the different procedures employed in performing four types of treatments for the preparation of aluminum and aluminum alloy surfaces for painting. These processes are broadly classified into the following treatment types: solvent cleaning (Type A); chemical treatments (Type B); anodic treatments (Type C); and mechanical treatments (Type D). Service conditions shall dictate the type of surface preparation that should be employed, although the quality produced by any individual method may still vary with the type of alloy involved. Solvent cleaning does not disturb the natural oxide film on the metal and is applicable in ambient indoor or very mild service conditions. This treatment type may be performed by three methods, as follows: manual swabbing or dip washing; solvent spray cleaning; or vapor degreasing. Chemical treatments may be employed by the following eight methods: alkaline cleaners; sulfuric acid, chromium trioxide etch; alcoholic phosphoric acid cleaner; crystalline phosphate treatment; amorphous phosphate treatment; carbonate chromate treatment; amorphous chromate treatment; or 8) acid-bound resinous treatment. Anodic treatments will provide a protective inert oxide coating which increases corrosion resistance and promotes paint adhesion. This is recommended where maximum corrosion resistance by the treatment itself is desired, but should not be used on assemblies of dissimilar metals. This treatment type may be executed by two methods, namely: sulfuric acid anodic, or chromium trioxide anodic treatment. Mechanical treatments may be implemented by these two methods: hand or power wire brushing or other abrasive treatment; or sandblasting.

Scope

1.1 These practices cover four types of treatment for preparation of aluminum and aluminum-alloy surfaces for painting, as follows:

1.1.1 Type A—Solvent Cleaning.

1.1.2 Type B—Chemical Treatments.

1.1.3 Type C—Anodic Treatments.

1.1.4 Type D—Mechanical Treatments. These four types cover a number of procedures, as described herein.

1.2 Variations in surface treatment produce end conditions which differ, and which do not necessarily yield identical results when paints are applied. Service conditions will dictate the type of surface preparation that should be selected, although the quality produced by any individual method may vary with different alloys.