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 (11)).4 An accepted standard test method for the use of such an instrument is long overdue.  
3.2 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.  
3.3 This test method, however, is useful within laboratories to quickly screen and measure the surface hardness of candidate coatings.
SCOPE
1.1 This test method covers the determination of the relative degree of surface hardness of organic coatings using a specific apparatus widely 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 and health practices and determine the applicability of regulatory limitations prior to use.

General Information

Status
Historical
Publication Date
31-Oct-2012
Current Stage
Ref Project

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ASTM D2134-93(2012) - Standard Test Method for Determining the Hardness of Organic Coatings with a Sward-Type Hardness Rocker
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: D2134 − 93 (Reapproved 2012)
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 D4138 Practices for Measurement of Dry Film Thickness of
Protective Coating Systems by Destructive, Cross-
1.1 Thistestmethodcoversthedeterminationoftherelative
Sectioning Means
degree of surface hardness of organic coatings using a specific
apparatus widely used in the coatings industry.
3. Significance and Use
1.2 The values stated in SI units are to be regarded as the
3.1 Sward-type hardness rocker instruments have been used
standard. The values given in parentheses are for information
by the coatings industry for more than a half a century as a
only.
nondestructive test instrument to measure cure and ultimate
1.3 This test method does not purport to address all of the
surface hardness of organic coatings (see Refs. (1) through
safety problems, if any, associated with its use. It is the
(11)). An accepted standard test method for the use of such an
responsibility of the user of this standard to establish appro-
instrument is long overdue.
priate safety and health practices and determine the applica-
3.2 In previous task group work designed to establish an
bility of regulatory limitations prior to use.
ASTM method for measuring hardness of organic coatings
with Sward-type hardness rocker instruments, round-robin test
2. Referenced Documents
resultscontinuallyshowedpoorinterlaboratoryreproducibility.
2.1 ASTM Standards:
This lack of interlaboratory agreement could have resulted
D823 Practices for Producing Films of Uniform Thickness
from dimensional variations among instruments, with the
of Paint, Varnish, and Related Products on Test Panels
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
ness of Organic Coatings Using Micrometers
making instruments that differ among themselves in net weight
D1186 Test Methods for Nondestructive Measurement of
and ring radius. Some of them exceed the measurements and
Dry Film Thickness of Nonmagnetic Coatings Applied to
net weight called for in this test method.
a Ferrous Base (Withdrawn 2006)
3.3 This test method, however, is useful within laboratories
D1400 TestMethodforNondestructiveMeasurementofDry
to quickly screen and measure the surface hardness of candi-
Film Thickness of Nonconductive Coatings Applied to a
date coatings.
Nonferrous Metal Base (Withdrawn 2006)
D3924 Specification for Environment for Conditioning and
4. Apparatus
Testing Paint, Varnish, Lacquer, and Related Materials
4.1 Hardness Tester—The hardness tester shall consist of
two flat, chromium-plated bronze rings with uniformly round
This test method is under the jurisdiction of ASTM Committee D01 on Paint
outside edges. These rings are separated and held in position
and Related Coatings, Materials, andApplications and is the direct responsibility of
with a weighted lower member and three horizontal light-
Subcommittee D01.23 on Physical Properties of Applied Paint Films.
Current edition approved Nov. 1, 2012. Published November 2012. Originally
weight spacer bars with the topmost one supporting a weight
approved in 1962. Last previous edition approved in 2007 as D2134 – 93 (2007).
adjustable in height. A rack across the center section supports
DOI: 10.1520/D2134-93R12.
2 two bubble tube-type levels that are used to measure the
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
amplitude of the oscillations of the hardness tester. The rate of
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 − 93 (2012)
change in amplitude is used as a measure of hardness or adjust the angle of the left-hand bubble tube to give the correct
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 ± 10 g
7. Conditioning
Diameter 10 ± 0.025 cm (4.000 ± 0.010 in.)
Width between 2.5 ± 0.0125 cm (1.000 ± 0.005 in.)
7.1 Conditioning—Condition the test specimens at 23 6
rings
Period 50 swings on glass plate in 60.0 ± 0.5 s 2°C (73.5 6 3.5°F) and 506 5 % relative humidity for not less
Calibration Decrease in amplitude of 6° taken between
than 24 h prior to test in accordance with Specification D3924,
approximately 22° and 16° from the vertical, after
for those tests where conditioning is required. In cases of
50 swings on glass
disagreement, the tolerances shall be 61°C (61.8°F) and
The hardness tester should be equipped with a clear cover to
62 % relative humidity.
protect it from air currents during operation.Asuitable tester is
illustrated in Fig. 1. 7.2 Test Conditions—Conduct tests in the standard labora-
tory atmosphere of 23 6 2°C (73.5 6 3.5°F) and 50 6 5%
4.2 Glass Plates—Glass panels approximately 15cm (6
2 relative humidity, unless otherwise specified in the test meth-
in. ) and a minimum of 2 mm (78 mils) thick are required.
ods or in Specification D3924. In cases of disagreement, the
Preferably these should be plate glass; however, carefully
tolerances shall be 61°C (61
...

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