ASTM D1731-03

Standard Practices for Preparation of Hot-Dip Aluminum Surfaces for Painting

ABSTRACT
These practices describe procedures for the preparation of hot-dip aluminum surfaces for painting. Two types of surface preparation are included: solvent cleaning and chemical treatments. Solvent cleaning of the surfaces may be done by any of the following methods: manual swabbing or dip washing with a solvent such as mineral spirits or high flask solvent naphtha, solvent spray cleaning, and vapor degreasing in special equipment. On the other hand, surface preparation of aluminum for painting may be achieved by any of the following chemical treatment methods: use of alkaline cleaners, use of alcoholic phosphoric acid cleaners, use of acid fluoride deoxidizer, crystalline phosphate treatment, amorphous phosphate treatment, carbon chromate treatment, amorphous chromate treatment, and acid-bound resinous treatment.
SCOPE
1.1 These practices describe procedures for the preparation of hot-dip aluminum surfaces for painting.
1.2 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 D1731-67(1998) - Standard Practices for Preparation of Hot-Dip Aluminum Surfaces for Painting
• Effective Date: 10-Sep-2003
• Replaced By: ASTM D1731-09 - Standard Practices for Preparation of Hot-Dip Aluminum Surfaces for Painting
• Effective Date: 15-Apr-2009
• Referred By: ASTM D6577-15(2019) - Standard Guide for Testing Industrial Protective Coatings
• Effective Date: 10-Sep-2003
• Referred By: ASTM D3322-23 - Standard Practice for Testing Primers and Primer Surfacers Over Preformed Metal
• Effective Date: 10-Sep-2003
• Referred By: ASTM B905-00(2021) - Standard Test Methods for Assessing the Adhesion of Metallic and Inorganic Coatings by the Mechanized Tape Test
• 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 D2454-23 - Standard Practice for Determining the Effect of Overbaking on Organic Coatings
• 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:D1731–03
Standard Practices for
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Preparation of Hot-Dip Aluminum Surfaces for Painting
This standard is issued under the fixed designation D 1731; 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.
1. Scope is extremely difficult to produce a clean metal surface by this
method. Accumulated contaminants in the solvent or on the
1.1 These practices describe procedures for the preparation
swab are frequently redeposited on the surface being prepared.
of hot-dip aluminum surfaces for painting.
4.3 Method 2—Solvent spray cleaning in accordance with
1.2 This standard may involve hazardous materials, opera-
Method A, Procedure 1 of Practice D 609.
tions, and equipment. This standard does not purport to
4.4 Method 3—Vapor degreasing in special equipment in
address all of the safety concerns, if any, associated with its
accordance with the latest revision of Method A, Procedure 2
use. It is the responsibility of the user of this standard to
of Practice D 609, employing trichlorethylene or perchloreth-
establish appropriate safety and health practices and deter-
ylenevapor.Solventcleaningdoesnotdisturbthenaturaloxide
mine the applicability of regulatory limitations prior to use.
film on the metal and may prove adequate for some applica-
2. Referenced Documents
tions.
2.1 ASTM Standards:
5. Chemical Treatment
D 609 Practice for Preparation of Cold-Rolled Steel Panels
5.1 The surfaces may be prepared for painting by any of the
for Testing Paint, Varnish, Conversion Coatings and Re-
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methods for chemical treatment (Note 1) described in 5.2 to
lated Coating Products
5.9:
2.2 Military Standards:
MIL-C-5541 Chemical Conversion Coatings on Aluminum
NOTE 1—Materials and procedures employed in these methods of
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and Aluminum Alloys treatment are available from a number of sources as proprietary com-
pounds or methods. Selection may be made from available sources. The
3. Types of Surface Preparations
hexavalent chromium methods given are not recommended as hexavalent
chromium is a known carcinogen.
3.1 Two types of surface preparations are covered as fol-
lows: 5.2 Method 1, Alkaline Cleaners—Etching alkaline solu-
3.1.1 Solvent Cleaning, and tions, such as caustic soda, should be avoided because of the
3.1.2 Chemical Treatments. possibility of dissolving away the aluminum coating thereby
3.2 These two types cover several methods as described in exposing the base metal. Since inhibited alkaline cleaners do
Section 5. Variations in surface treatment produce end condi- notetchthesurface,theycanbeusedtoremovegrease,oil,and
tions which differ and which do not necessarily yield identical other organic solids from hot dip aluminum. After alkali
results when paints are applied. Service conditions will dictate cleaning, the surface should be thoroughly rinsed with clean
the type of surface preparation that should be selected. water. Most often alkaline-cleaned surfaces are subsequently
processed by one of the following methods, described in
4. Solvent Cleaning
5.3-5.9.
4.1 The surfaces may be prepared for painting by any of the
5.3 Method 2, Alcoholic Phosphoric Acid Cleaners—This
methods for solvent cleaning described in 4.2 and 4.3. treatment involves the use of an aqueous solution of phospho-
4.2 Method 1—Manual swabbing or dip washing with a
ric acid with alcohol or other organic solvents, together with
solvent such as mineral spirits or high flask solvent naphtha. It wetting agents, emulsifying agents, etc. The solution may be
applied by swabbing or dipping (preferably at a temperature of
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70 to 90°F (21 to 32°C)). The solution should remain on the
ThesepracticesareunderthejurisdictionofASTMCommitteeB08onMetallic
and Inorganic Coatings and is the direct responsibility of Subcommittee B08.07 on
surface for several minutes, followed by thorough rinsing with
Chromate Conversion Coatings.
clean water. A very thin phosphate film is formed which tends
Current edition approved Sept. 10, 2003. Published Sept. 2003. Originally
to protect the metal and promote paint adhesion.
approved in 1960. Last previous edition approved in 1998 as D 1731 – 67 (1998).
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Annual Book of ASTM Standards, Vol 06.01.
NOTE 2—Materials meeting the requirements of the latest revision of
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Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,
U.S. Military Specification MIL-M-10578B may be used.
Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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