ASTM D1730-03

Standard Practices for Preparation of Aluminum and Aluminum-Alloy Surfaces for Painting

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.
1.3 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 09-Sep-2003
• ICS: 87.020 - Paint coating processes
• Technical Committee: B08 - Metallic and Inorganic Coatings
• Drafting Committee: B08.07 - Conversion Coatings

Relations

• Replaces: ASTM D1730-67(1998) - Standard Practices for Preparation of Aluminum and Aluminum-Alloy Surfaces for Painting
• Effective Date: 10-Sep-2003
• Replaced By: ASTM D1730-09 - Standard Practices for Preparation of Aluminum and Aluminum-Alloy Surfaces for Painting
• Effective Date: 15-Apr-2009
• Referred By: ASTM D870-15(2020) - Standard Practice for Testing Water Resistance of Coatings Using Water Immersion
• Effective Date: 10-Sep-2003
• Referred By: ASTM D822/D822M-13(2018) - Standard Practice for Filtered Open-Flame Carbon-Arc Exposures of Paint and Related Coatings
• Effective Date: 10-Sep-2003
• Referred By: ASTM D6577-15(2019) - Standard Guide for Testing Industrial Protective Coatings
• Effective Date: 10-Sep-2003
• Referred By: ASTM D6695-16 - Standard Practice for Xenon-Arc Exposures of Paint and Related Coatings
• Effective Date: 10-Sep-2003
• Referred By: ASTM D6675-23 - Standard Practice for Salt-Accelerated Outdoor Cosmetic Corrosion Testing of Organic Coatings on Automotive Sheet Steel
• Effective Date: 10-Sep-2003
• Referred By: ASTM D4585/D4585M-18 - Standard Practice for Testing Water Resistance of Coatings Using Controlled Condensation
• Effective Date: 10-Sep-2003
• Referred By: ASTM D2803-09(2020) - Standard Guide for Testing Filiform Corrosion Resistance of Organic Coatings on Metal
• Effective Date: 10-Sep-2003
• Referred By: ASTM D2248-01a(2018) - Standard Practice for Detergent Resistance of Organic Finishes
• Effective Date: 10-Sep-2003
• Referred By: ASTM D2247-15(2020) - Standard Practice for Testing Water Resistance of Coatings in 100 % Relative Humidity
• Effective Date: 10-Sep-2003
• Referred By: ASTM D2454-23 - Standard Practice for Determining the Effect of Overbaking on Organic Coatings
• Effective Date: 10-Sep-2003
• Referred By: ASTM D3451-06(2017) - Standard Guide for Testing Coating Powders and Powder Coatings
• Effective Date: 10-Sep-2003
• Referred By: ASTM D1014-18 - Standard Practice for Conducting Exterior Exposure Tests of Paints and Coatings on Metal Substrates
• Effective Date: 10-Sep-2003
• Referred By: ASTM D3276-21 - Standard Guide for Painting Inspectors (Metal Substrates)
• Effective Date: 10-Sep-2003

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D 1730 – 03
Standard Practices for
Preparation of Aluminum and Aluminum-Alloy Surfaces for
1
Painting
This standard is issued under the fixed designation D 1730; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope such as ambient indoor or very mild service conditions. Three
methods may be employed, as follows:
1.1 These practices cover four types of treatment for prepa-
3.1.1 Method 1, Manual Swabbing or Dip-Washing, with a
ration of aluminum and aluminum-alloy surfaces for painting,
solvent such as mineral spirits or high-flask solvent naphtha.
as follows:
With this method it is extremely difficult to prevent accumu-
1.1.1 Type A—Solvent Cleaning.
lation of contaminants on the swab or in the solvent. This
1.1.2 Type B—Chemical Treatments.
method is only recommended when other treatments are
1.1.3 Type C—Anodic Treatments.
impractical.
1.1.4 Type D—Mechanical Treatments. These four types
3.1.2 Method2,SolventSprayCleaning, in accordance with
cover a number of procedures, as described herein.
Method A, Procedure 1 of Practice D 609.
1.2 Variations in surface treatment produce end conditions
3.1.3 Method 3, Vapor Degreasing, in special equipment
which differ, and which do not necessarily yield identical
employing trichloroethylene vapor, in accordance with Method
results when paints are applied. Service conditions will dictate
A, Procedure 2 of Practice D 609.
the type of surface preparation that should be selected, al-
though the quality produced by any individual method may
4. Type B—Chemical Treatments
vary with different alloys.
NOTE 1—Materials and procedures employed in these methods of
1.3 This standard may involve hazardous materials, opera-
treatment are available from a number of sources as proprietary com-
tions, and equipment. This standard does not purport to
pounds or methods. Selection may be made from available sources. The
address all of the safety concerns, if any, associated with its
hexavalent chromium methods given are not recommended as hexavalent
use. It is the responsibility of the user of this standard to
chromium is a known carcinogen.
establish appropriate safety and health practices and deter-
4.1 Method 1, Alkaline Cleaners—Alkaline solutions, such
mine the applicability of regulatory limitations prior to use.
as caustic soda, etch the metal, thus destroying the natural
oxide film. They are followed by an acid treatment, preferably
2. Referenced Documents
nitric acid or phosphoric acid. They shall not be used on
2.1 ASTM Standards:
assembledstructures.Inhibitedalkalinecleanersaresometimes
D 609 Practice for Preparation of Cold-Rolled Steel Panels
employedasapretreatmenttoremovegreaseandoilpriortoan
for Testing Paint, Varnish, Conversion Coatings and Re-
acid treatment. Inhibited alkaline cleaners do not etch the
2
lated Coating Products
surface. They are not generally recommended unless followed
2.2 Military Standards:
by a conversion treatment, such as described in Methods 4, 5,
MIL-C-5541 Chemical Conversion Coatings on Aluminum
6, or 7.
3
and Aluminum Alloys
4.2 Method 2, Sulfuric Acid, Chromium Trioxide Etch—
This treatment provides a clean and uniform surface without
3. Type A—Solvent Cleaning
undue etching, and is effective for removing oil and water
3.1 Solvent cleaning does not disturb the natural oxide film
stains and any film formed during heat-treatment. The etching
on the metal and may prove adequate for some applications,
solution is prepared by adding 1 gal (3.78 L) of concentrated
sulfuric acid and 45 oz (1.28 kg) of chromium trioxide to 9 gal
1
ThesepracticesareunderthejurisdictionofASTMCommitteeB08onMetallic
(34 L) of water. It is used at a temperature of 160 to 180°F (71
and Inorganic Coatings and is the direct responsibility of Subcommittee B08.07 on
to 82°C) (depending on the alloy and the amount of film) for
Chromate Conversion Coatings.
Current edition approved Sept. 10, 2003. Published Sept. 2003. Originally about 5 min and is followed by a water rinse. This treatment
approved in 1960. Last previous edition approved in 1998 as D 1730-67 (1998).
produces a passive surface suitable for painting under mild to
2
Annual Book of ASTM Standards, Vol 06.01.
intermediate exposure conditions and where clear finishes are
3
Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,
to be applied.
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