ASTM D1730-03

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Designation: D 1730 – 03
Standard Practices for
Preparation of Aluminum and Aluminum-Alloy Surfaces for
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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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