ASTM D2134-93

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Designation: D 2134 – 93
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Test Method for
Determining the Hardness of Organic Coatings with a
Sward-Type Hardness Rocker
This standard is issued under the fixed designation D 2134; 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 3.2 In previous task group work designed to establish an
ASTM method for measuring hardness of organic coatings
1.1 This test method covers the determination of the relative
with Sward-type hardness rocker instruments, round-robin test
degree of surface hardness of organic coatings using a specific
results continually showed poor interlaboratory reproducibility.
apparatus widely used in the coatings industry.
This lack of interlaboratory agreement could have resulted
1.2 This test method does not purport to address all of the
from dimensional variations among instruments, with the
safety problems, if any, associated with its use. It is the
contact rocker rings as the most likely offender in that regard.
responsibility of the user of this standard to establish appro-
There are several producers of Sward-type hardness rockers
priate safety and health practices and determine the applica-
making instruments that differ among themselves in net weight
bility of regulatory limitations prior to use.
and ring radius. Some of them exceed the measurements and
2. Referenced Documents
net weight called for in this test method.
3.3 This test method, however, is useful within laboratories
2.1 ASTM Standards:
to quickly screen and measure the surface hardness of candi-
D 823 Practices for Producing Films of Uniform Thickness
date coatings.
of Paint, Varnish, Lacquer, and Related Products on Test
Panels
4. Apparatus
D 1005 Test Methods for Measurement of Dry-Film Thick-
2 4.1 Hardness Tester —The hardness tester shall consist of
ness of Organic Coatings Using Micrometers
two flat, chromium-plated bronze rings with uniformly round
D 1186 Test Methods for Nondestructive Measurement of
outside edges. These rings are separated and held in position
Dry Film Thickness of Nonmagnetic Coatings Applied to
with a weighted lower member and three horizontal light-
a Ferrous Base
weight spacer bars with the topmost one supporting a weight
D 1400 Methods for Nondestructive Measurement of Dry
adjustable in height. A rack across the center section supports
Film Thickness of Nonconductive Coatings Applied to a
two bubble tube-type levels that are used to measure the
Nonferrous Metal Base
amplitude of the oscillations of the hardness tester. The rate of
D 3924 Specification for Standard Environment for Condi-
change in amplitude is used as a measure of hardness or
tioning and Testing Paint, Varnish, Lacquer, and Related
softness of the test surface. The hardness tester shall meet the
Materials
following characteristics:
D 4138 Test Method for Measurement of Dry Film Thick-
Weight 100 6 10 g
ness of Protective Coating Systems by Destructive Means
Diameter 4.000 6 0.010 in. (10 6 0.025 cm)
Width between 1.000 6 0.005 in. (2.5 6 0.0125 cm)
3. Significance and Use
rings
Period 50 swings on glass plate in 60.0 6 0.5 s
3.1 Sward-type hardness rocker instruments have been used
Calibration Decrease in amplitude of 6° taken between ap-
by the coatings industry for more than a half a century as a
proximately 22° and 16° from the vertical, after
nondestructive test instrument to measure cure and ultimate
50 swings on glass
surface hardness of organic coatings (see Refs. (1) through
The hardness tester should be equipped with a clear cover to
(11)). An accepted standard test method for the use of such an
protect it from air currents during operation. A suitable tester is
instrument is long overdue.
illustrated in Fig. 1.
4.2 Glass Plates—Glass panels approximately 6 in. (15
This test method is under the jurisdiction of ASTM Committee D-1 on Paint
cm ) and a minimum of 78 mils (2 mm) thick are required.
and Related Coatings, Materials, and Applications and is the direct responsibility of
Subcommittee D01.23 on Physical Properties of Applied Paint Films.
Current edition approved Oct. 15, 1993. Published December 1993. Originally
The Erichsen (Germany) Hardness Rocker, available from T. J. Bell, Inc., 1340
published as D 2134 – 62. Last previous edition D 2134 – 66 (1980).
Annual Book of ASTM Standards, Vol 06.01. Home Ave., Akron, OH 44310 and Paul N. Gardner Company, Inc., 316 N.E. First
Annual Book of ASTM Standards, Vol 06.02. Street, Pompano Beach, FL 33060 and Sward-type Sheen (England) Hardness
Boldface numbers in parentheses refer to the list of references at the end of this Rockers, available from Paul N. Gardner Company, Inc., 316 N.E. First Street,
test method. Pompano Beach, FL 33060, have been found satisfactory for this purpose.
D 2134
FIG. 1 Rocker Hardness Tester
Preferably these should be plate glass; however, carefully relative humidity, unless otherwise specified in the test meth-
inspected smooth window glass may be substituted. ods or in Specification D 3924. In cases of disagreement, the
tolerances shall be 61.8°F (61°C) and 62 % relative humid-
5. Test Specimen
ity.
5.1 The substrate shall be at leasta2by4by 0.01-in. (50 by
8. Procedure
100 by 0.25-mm) smooth piece.
8.1 Prepare three panels of the organic coating to be tested
5.2 The organic coating specimen shall be a thin film on the
in accordance with one of the practices described in Practices
sub
...