ASTM D1212-91(2013)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D1212 − 91 (Reapproved 2013)
Standard Test Methods for
Measurement of Wet Film Thickness of Organic Coatings
This standard is issued under the fixed designation D1212; 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 3.3 InTest Method B, a gage with a convex lower surface is
pushed into the wet film until the center touches the substrate.
1.1 These test methods cover the determination of wet film
The diameter of the spot of wet coating left on the convex
thickness of organic coatings such as paint, varnish, and
surface is measured and the film thickness calculated from the
lacquer. Two methods are described as follows:
diameter of the spot and the radius of curvature.
1.1.1 In Test Method A, the Wet Film Thickness Gage
(English or Metric graduation (see 5.1)) is used to measure wet
4. Significance and Use
film thicknesses up to 60 mils on the English scale series, and
4.1 Wet film thickness measurements aid in the prediction
up to 700 µm on the metric scale series (Sections5–8).
of dry film thickness. In instances where dry film thickness
1.1.2 In Test Method B, the Pfund Gage is used to measure
cannot be measured nondestructively, wet film thickness is
wet film thicknesses up to 14.2 mils (360 µm) (Sections9–
frequently specified. Also, the ability to determine wet film
13).
thickness during application can provide the opportunity to
1.2 The values stated in SI units are to be regarded as the
correct the application procedures.
standard. The values given in parentheses are for information
only.
TEST METHOD A
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
5. Apparatus
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- 5.1 WetFilmThicknessGage—Twoversionsofthegageare
now in use: The original design as shown in Fig. 1 and a later
bility of regulatory limitations prior to use.
designasshowninFig.2.Bothdesignsconsistsofaneccentric
2. Referenced Documents
center wheel supported by two concentric wheels so as to
2.1 ASTM Standards: providetwoscalesthatarebilaterallysymmetrical.Asthegage
D823 Practices for Producing Films of Uniform Thickness is rolled on the film, there is a change in clearance between the
of Paint, Varnish, and Related Products on Test Panels wet film and the eccentric wheel. The point at which the film
first touches the center wheel measures the thickness of the
3. Summary of Test Methods
film.
3.1 The material is applied in the laboratory to plane, rigid
5.2 The later design shown in Fig. 2, moves the eccentric
test panels or in the field to the surface being coated. The wet
wheel from between the concentric wheels, as shown in Fig. 1,
film thickness is determined as quickly as possible to reduce
to the outside of the gage and closer to one of the concentric
shrinkage due to solvent loss.
wheels. Gage reading errors of parallax across the gage are
3.2 In Test Method A, a gage with one eccentric and two eliminatedasthetwoscalesareplaceddirectlyontheeccentric
concentricwheelsisrolledoverthesurfaceandthepointwhere wheel and errors when measuring on uneven support surfaces
the eccentric wheel first touches the wet film is determined. are reduced by placing the eccentric wheel closer to one of the
supporting concentric wheels.
These test methods are under the jurisdiction of ASTM Committee D01 on
5.3 Best precision is obtained when using the near linear
Paint and Related Coatings, Materials, and Applications and are the direct
central portion of each scale, constituting about 80 % of its
responsibility of Subcommittee D01.23 on Physical Properties of Applied Paint
Films.
Current edition approved July 1, 2013. Published July 2013. Originally approved
ε1
in 1952. Last previous edition approved in 2007 as D1212 – 91 (2007) . DOI: Both versions of this gage (Interchemical (INMONT) and Model “C”) are
10.1520/D1212-91R13. covered by U.S. Patents 2 507 592 and 3 128 558 and are issued to Maynard R.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Euverard. Interested parties are invited to submit information regarding the
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM identification of acceptable alternatives to this patented item to the Committee on
Standards volume information, refer to the standard’s Document Summary page on Standards, ASTM Headquarters. Your comments will receive careful consideration
the ASTM website. at a meeting of the responsible technical committee, which you may attend.
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D1212 − 91 (2013)
FIG. 1 Interchemical Wet Film Thickness Gages
FIG. 2 Model “C” Wet Film Thickness Gages
total range as shown in the diagram in Fig. 1 and Fig. 2. film thickness measurements at least 25 mm (1 in.) from any
Therefore, the range of the particular gage selected for use edge. Determine the film thickness immediately after applica-
should be such that the measured film thickness falls within,
tion.
and preferably toward the center of the middle 80 % of each
6.2 Support the test panels on a suitable level base in such
scale. Gages are available covering the following ranges in
a way that there will be no movement or spring of the panels
mils and microns:
during the film thickness measurements. Place the gage on the
Smallest
Range, mils
wet film so that the minimum marking is at the top and the
Graduation, mils
0to2 0.1
greatest clearance between the eccentric wheel and the film is
0to4 0.2
directly over the wet film. Roll the gage over the film one-half
2to12 0.5
10 to 30 1.0 revolution in one direction toward the minimum marking on
20 to 60 2.0
the gage and repeat in the opposite direction. Read the points
Smallest
Range, µm at which the coating first makes contact with the eccentric
Graduation, µm
wheel and determine the mean which is considered as one
0to40 2.0
0 to 100 5.00
reading.
50 to 250 10.00
200 to 700 25.00
6.3 If the coating contains a solvent that evaporates rapidly
or if the solids content is low, make at least a second separate
6. Procedure
reading on a freshly applied film and calculate the mean of the
6.1 ApplythematerialinaccordancewithPracticesD823to
separate readings.
suitable plane rigid panels of area sufficiently large to permit
D1212 − 91 (2013)
7. Report
7.1 Report the mean of the separate readings and the range
and smallest graduation of the gage used.
8. Precision
8.1 In an interlaboratory study of this test method, in which
two operators in at least six laboratories made measurements
with the 0- to 2- and 0- to 4-mil gages on three materials,
applied at two film thicknesses, the pooled within-laboratory
standarddeviationwasfoundtobe0.12milswith34dfandthe
between-laboratori
...