ASTM D2691-88

Method for Microscopical Measurement of Dry Film Thickness of Coatings on Wood Products (Withdrawn 1992)

General Information

• Status: Withdrawn
• Withdrawal Date: 14-May-1992
• ICS: 87.040 - Paints and varnishes
• Technical Committee: D01 - Paint and Related Coatings, Materials, and Applications
• Drafting Committee: D01.52 - Factory Coated Wood Products

Standards Content (Sample)

/+o4 74
ASTM D2693 88 = 0759530 002bï03 b W
AMERICAN SOCIETY FOR TESTINQ AND MATERIALS
1916 Race SI., Philadelphia, Pa. í9103
([lb Designation: D 2691 - 88
Reprinted from the Annual Book of ASTM Standards, Copyright ASTM
If not listed in the current comb!ned Index, will appear in the next edition.
Standard Test Methods for
Microscopical Measurement of Dry Film Thickness of
Coatings on Wood Products1s2
This standard is issued under the fixed designation D 2691; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of lasf revision. A number in parentheses indicafes the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 . These test methods cover the measurement of film
thickness of dried coatings applied to a plane rigid substrate
Punch
of wood or a wood-base material. These test methods apply
to both opaque and clear coatings. They are not recom-
mended for metal or glass substrates. Test Method A uses a
razor blade and Test Method B a microtome for cross
sectioning.
V///////////////////////////1 Push Rad (fell-lipped)
1.2 This standard may involve hazardous materials, oper-
ations, and equipment. This standard does not purport to
address all of the safety problems associated with its use. It is FIG. 1 One Type of Tool for Extracting Coated Wood Specimens
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.
removal intact within the punch.
3.3 Source of Oblique Illumination,
2. Significance and Use
3.4 Hand Microtome (Method B).
2.1 This test method provides a precise, quantitative
measurement of the thickness of a dried coating. It may be 4. Test Specimens
used for quality control or monitoring of the production of
4.1 Specimens for microscopical measurement shall be
coated wood products.
extracted from the punch tool by means of a push rod
inserted through the hollow shaft of its tube. The end of the
3. Apparatus
push rod should be tipped with felt or other soft material so
3.1 Calibrated Monocular Compound Microscope, that the coated surface of the disk will not be damaged
equipped with an optical system sufficient to provide sharp during extraction.
resolution of the cross section to be examined. One system,
consisting of a 16-mm objective and a 10-power filar
5. Procedure
micrometer eyepiece, resulting in a magnification of approx-
5.1 Prepare disks for microscopical examination and meas-
imately 100 diameters, has been found satisfactory. Other
urement by either Method A or Method B. Either method of
combinations of objectives and eyepieces and other magnifi-
preparation will expose a cross section of coating and sub-
cations may also be suithble, although magnifications above
sfrate, including the extremes in film thickness resulting
200 diameters may result in distortion of the viewed cross
from variations in the wood surface or method of application.
section.
5.2 Method A, Cross Sectioning with Razor Blade-With
3.2 Tool for Extracting Test Specimens-The tool may be
a sharp razor blade carefully slice away parallel to the coated
similar in design to an ordinary cork borer, except that it
surface the substrate adhering to the coating until the disk is
shall be made of thicker walled tubing, hard enough to hold
approximately '/I6 in. (1.6 mm) thick. Place the disk coated
a keen cutting edge, and be fitted with a head suitable for
face down on a smooth, hard surface and cut in half by
pounding with a hammer (Fig. i). A leather punch has been
means of a slicing stroke with a fresh razor blade (Fig. 2). Cut
found satisfactory for this use. The tool shall make a circular
in a direction perpendicular to the grain of the wood
cut approximately Y2 in. (12.7 mm) in diameter and 1/13 in.
substrate and at right angles to the coated surface.
(3.2 mm) deep through the coating and into the substrate. A
5.3 Method B, Cross Sectioning with Microtome:
sidewise movement of the punch while firmly embedded in
5.3.1 With a sharp razor blade carefully slice away parallel
the substrate wiil dislodge the specimen and allow its
to the coated surface the substrate adhering to the coating
-
until the disk is approximately '/I6 in. (I .6 mm) thick.
5.3.2 Embed the thinned disk in molten paraffin3 which is
These test methods are under the jurisdiction of ASTM Committee D-1 on
Painf and Related Coatings and Materials and are the direct responsibility of
Subcommittee W1.52 on Factory-Coated Wood Products.
Current edition approved March 29, 1988. Published May 1988. Originally Paraplast, available from Fischer Scientific, 191 South Gulph Road, P.O. Box
published as D 2691 - 68. Last previous edition D 2691 - 70 (1981)".
J, King of Pnissia, PA 19406 melting point about 50 to 6
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