ASTM D2134-19(2024)
(Test Method)Standard Test Method for Determining the Hardness of Organic Coatings with a Sward-Type Hardness Rocker
Standard Test Method for Determining the Hardness of Organic Coatings with a Sward-Type Hardness Rocker
SIGNIFICANCE AND USE
3.1 Sward-type hardness rocker instruments have been used by the coatings industry for more than a half a century as a nondestructive test instrument to measure cure and ultimate surface hardness of organic coatings (see Refs. (1) through (2)).4 This test method is useful within laboratories to quickly screen and measure the surface hardness of candidate coatings.
Note 1: In previous task group work designed to establish an ASTM method for measuring hardness of organic coatings with Sward-type hardness rocker instruments, round-robin test results continually showed poor interlaboratory reproducibility. This lack of interlaboratory agreement could have resulted from dimensional variations among instruments, with the contact rocker rings as the most likely offender in that regard. There are several producers of Sward-type hardness rockers making instruments that differ among themselves in net weight and ring radius. Some of them exceed the measurements and net weight called for in this test method.
SCOPE
1.1 This test method covers the determination of the relative degree of surface hardness of organic coatings using a specific apparatus used in the coatings industry.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.3 This test method does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D2134 − 19 (Reapproved 2024)
Standard Test Method for
Determining the Hardness of Organic Coatings with a
Sward-Type Hardness Rocker
This standard is issued under the fixed designation D2134; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope Nonferrous Metal Base (Withdrawn 2006)
D3924 Specification for Standard Environment for Condi-
1.1 This test method covers the determination of the relative
tioning and Testing Paint, Varnish, Lacquer, and Related
degree of surface hardness of organic coatings using a specific
Materials
apparatus used in the coatings industry.
D4138 Practices for Measurement of Dry Film Thickness of
1.2 The values stated in SI units are to be regarded as the
Protective Coating Systems by Destructive, Cross-
standard. The values given in parentheses are for information
Sectioning Means
only.
E177 Practice for Use of the Terms Precision and Bias in
1.3 This test method does not purport to address all of the
ASTM Test Methods
safety problems, if any, associated with its use. It is the E691 Practice for Conducting an Interlaboratory Study to
responsibility of the user of this standard to establish appro-
Determine the Precision of a Test Method
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use. 3. Significance and Use
1.4 This international standard was developed in accor-
3.1 Sward-type hardness rocker instruments have been used
dance with internationally recognized principles on standard-
by the coatings industry for more than a half a century as a
ization established in the Decision on Principles for the
nondestructive test instrument to measure cure and ultimate
Development of International Standards, Guides and Recom-
surface hardness of organic coatings (see Refs. (1) through
mendations issued by the World Trade Organization Technical 4
(2)). This test method is useful within laboratories to quickly
Barriers to Trade (TBT) Committee.
screen and measure the surface hardness of candidate coatings.
NOTE 1—In previous task group work designed to establish an ASTM
2. Referenced Documents
method for measuring hardness of organic coatings with Sward-type
2 hardness rocker instruments, round-robin test results continually showed
2.1 ASTM Standards:
poor interlaboratory reproducibility. This lack of interlaboratory agree-
D823 Practices for Producing Films of Uniform Thickness
ment could have resulted from dimensional variations among instruments,
of Paint, Coatings and Related Products on Test Panels
with the contact rocker rings as the most likely offender in that regard.
D1005 Test Method for Measurement of Dry-Film Thick- There are several producers of Sward-type hardness rockers making
instruments that differ among themselves in net weight and ring radius.
ness of Organic Coatings Using Micrometers
Some of them exceed the measurements and net weight called for in this
D1186 Test Methods for Nondestructive Measurement of
test method.
Dry Film Thickness of Nonmagnetic Coatings Applied to
a Ferrous Base (Withdrawn 2006)
4. Apparatus
D1400 Test Method for Nondestructive Measurement of Dry
4.1 Hardness Tester—The hardness tester shall consist of
Film Thickness of Nonconductive Coatings Applied to a
two flat, chromium-plated bronze rings with uniformly round
outside edges. These rings are separated and held in position
with a weighted lower member and three horizontal light-
This test method is under the jurisdiction of ASTM Committee D01 on Paint
weight spacer bars with the topmost one supporting a weight
and Related Coatings, Materials, and Applications and is the direct responsibility of
Subcommittee D01.23 on Physical Properties of Applied Paint Films.
adjustable in height. A rack across the center section supports
Current edition approved Jan. 15, 2024. Published January 2024. Originally
two bubble tube-type levels that are used to measure the
approved in 1962. Last previous edition approved in 2019 as D2134 – 19. DOI:
amplitude of the oscillations of the hardness tester. The rate of
10.1520/D2134-19R24.
change in amplitude is used as a measure of hardness or
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
3 4
The last approved version of this historical standard is referenced on Boldface numbers in parentheses refer to the list of references at the end of this
www.astm.org. test method.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2134 − 19 (2024)
softness of the test surface. The hardness tester shall meet the value. The time for 50 swings can be changed by adjustments
following characteristics: in the position of the weight on the vertical screw.
Weight 100 g ± 10 g
7. Conditioning
Diameter 10 cm ± 0.025 cm (4.000 in. ± 0.010 in.)
Width between 2.5 cm ± 0.0125 cm (1.000 in. ± 0.005 in.)
7.1 Conditioning—Condition the test specimens at 23 °C 6
rings
Period 50 swings on glass plate in 60.0 s ± 0.5 s 2 °C (73.5 °F 6 3.5 °F) and 50 % 6 5 % relative humidity for
Calibration Decrease in amplitude of 6° taken between
not less than 24 h prior to test in accordance with Specification
approximately 22° and 16° from the vertical, after
D3924, for those tests where conditioning is required. In cases
50 swings on glass
of disagreement, the tolerances shall be 6 1 °C (6 1.8 °F) and
The hardness tester should be equipped with a clear cover to
6 2 % relative humidity.
protect it from air currents during operation. A suitable tester is
illustrated in Fig. 1. 7.2 Test Conditions—Conduct tests in the standard labora-
2 tory atmosphere of 23 °C 6 2 °C (73.5 °F 6 3.5 °F) and 50 %
4.2 Glass Plates—Glass panels approximately 15 cm
6 5 % relative humidity, unless otherwise specified in the test
(6 in. ) and a minimum of 2 mm (78 mils) thick are required.
methods or in Specification D3924. In cases of disagreement,
Preferably these should be plate glass; however, carefully
the tolerances shall be 6 1 °C (6 1.8 °F) and 6 2 % relative
inspected smooth window glass may be substituted.
humidity.
5. Test Specimen
8. Procedure
5.1 The substrate shall be at least a 50 mm by 100 mm by
8.1 Prepare three panels of the organic coating to be tested
0.25 mm (2 in. by 4 in. by 0.01 in.) smooth piece.
in accordance with one of the practices described in Practices
5.2 The organic coating specimen shall be a thin film on the
D823. Prior to testing, condition the panels for 7 days at the
substrate with a dry thickness of 25 μm to 50 μm (1 mils to
conditions specified in Section 7.
2 mils). Other dry film thicknesses can be used if agreed upon
8.2 Measure the dry film thickness of the organic coating
between the purchaser and the seller. It is very important that
using Test Methods D1005, D1186, D1400, or D4138.
the dry film thickness is uniform.
8.3 Determine the initial hardness of the coated panel in
5.3 The organic coating shall be air dried or heat cured, or
duplicate, using the procedure in Section 6, measuring parallel
both, using recommended conditions dependent upon the type
to the long direction of the coating. The number of complete
of organic coating. Only coatings visually free of holes, craters,
oscillations multiplied by 2 gives the hardness value.
orange peel, dust specks, or other surface irregularities shall be
used for this test.
NOTE 2—The rings of the hardness tester should be cleaned after each
measurement with acetone or other suitable solvent and polished with a
6. Calibration of Hardness Tester dry, lint-free cloth.
NOTE 3—With clear organic coatings, inspect the panel from the back
6.1 Calibrate the hardness tester on plate glass placed on a
side to determin
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