ASTM D660-93
(Test Method)Standard Test Method for Evaluating Degree of Checking of Exterior Paints
Standard Test Method for Evaluating Degree of Checking of Exterior Paints
SCOPE
1.1 The illustrated reference standards included in this test method are representative of degrees and types of checking of exterior paint films. These standards are primarily intended for comparative evaluation.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 660 – 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
Standard Test Method for
1
Evaluating Degree of Checking of Exterior Paints
This standard is issued under the fixed designation D 660; 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 surface of the film form in a definite three-pronged pattern with
the breaks running from a center and forming an angle of about
1.1 The illustrated reference standards included in this test
120° between the prongs.
method are representative of degrees and types of checking of
5.1.5 Mosaic Type—Checking in which the breaks in the
exterior paint films. These standards are primarily intended for
surface of the film form straight sided, geometric patterns
comparative evaluation.
which join on all sides.
2. Referenced Documents
5.1.6 Shrinkage Type—Checking in which the breaks in the
surface of the film usually form individual short breaks with
2.1 ASTM Standards:
shorter irregular breaks progressing at right angles.
D 661 Test Method for Evaluating Degree of Cracking of
2
5.1.7 Short, Random Type—Checking in which breaks in
Exterior Paints
the surface of the film form short, irregular patterns. These
3. Terminology
breaks are usually individual and do not join.
5.1.8 Sigmoid Type—Checking in which the breaks in the
3.1 Definition:
surface of the film form oval patterns. These oval shapes rarely
3.1.1 checking—that phenomenon manifested in paint films
complete their circle.
by slight breaks in the film that do not penetrate through the
last applied coating. Where precision is necessary in evaluating
3
6. Use of Illustrated Reference Standards
a paint film, checking may be described as visible (as seen with
6.1 The use of the reference standards shown in Fig. 1
the naked eye) or as microscopic (as observed under a
requires the following precautions:
magnification up to ten diameters).
6.1.1 Since the type and degree of failure may vary over any
4. Significance and Use
given area, a representative portion should be rated. It is
recommended that ratings be made at several locations, noting
4.1 Since checking is not easily recognizable, this test
types and degree of failure.
method is intended to provide, through definition and illustra-
6.1.2 Care must be taken to recognize that several types of
tions, a means of evaluating the degree of this film failure.
checking may be present on the same surface.
5. Types of Checking
6.1.3 Paint films may collect excessive quantities of dirt,
which may mask the type and degree of failure. If necessary,
5.1 Many types of checking are recognized, of which some
dirt should be removed by careful and
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.