ASTM D823-95(2001)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
Designation: D 823 – 95 (Reapproved 2001)
Standard Practices for
Producing Films of Uniform Thickness of Paint, Varnish,
and Related Products on Test Panels
This standard is issued under the fixed designation D 823; 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.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope tioning and Testing Paint, Varnish, Lacquer and Related
Materials
1.1 Five practices are given for preparing films of uniform
thickness of coatings on test panels. These practices are:
PRACTICE A—AUTOMATIC SPRAY MACHINE
Practice A—Automatic Spray Machine Application
APPLICATION
Practice B—Motor-Driven Dip Coater Application
Practice C—Motor-Driven Blade Film Application
3. Summary of Practices
Practice D—Hand-Held Spray Gun Application
3.1 A liquid material is applied to a test panel by means of
Practice E—Hand-Held Blade Film Application
an automatic spray machine consisting of a mounted spray gun
1.2 The values stated in SI units are to be regarded as the
and a panel holder. This machine can (1) move the panel
standard. The values given in parentheses are for information
holder, with test panel, at a uniform speed through the
only.
atomized spray produced by a fixed spray gun, or (2)itcan
1.3 This standard does not purport to address all of the
move the gun, with atomized spray, at a uniform speed past the
safety concerns, if any, associated with its use. It is the
test panel mounted on a fixed panel holder. A machine
responsibility of the user of this standard to establish appro-
equipped with a programmable system can index the spray gun
priate safety and health practices and determine the applica-
vertically for multiple passes and for multiple coats with
bility of regulatory limitations prior to use.
selective time delay.
3.2 The thickness of coating applied is controlled by the
2. Referenced Documents
traverse speed of the panel or gun, the fluid delivery rate of the
2.1 ASTM Standards:
gun, the viscosity of the material, and the amount of nonvola-
D 609 Practice for Preparation of Cold-Rolled Steel Panels
tile matter in the material.
for Testing Paint, Varnish, Conversion Coatings, and
Related Coating Products
4. Significance and Use
D 1005 Test Methods for Measurement of Dry Film Thick-
4.1 These practices should be used for those coatings that
ness of Organic Coatings Using Micrometers
are designed for spray applications of objects in the factory or
D 1186 Test Methods for Nondestructive Measurement of
in the field. It is particularly important that it be used in the
Dry Film Thickness of Nonmagnetic Coatings Applied to
evaluation of metallic coatings for appearance properties, such
a Ferrous Base
as gloss and color.
D 1212 Test Methods for Measurement of Wet Film Thick-
4.2 Coatingsappliedbythistestmethodmayexhibitaslight
ness of Organic Coatings
orange-peel or spray wave.
D 1400 Test Method for Nondestructive Measurement of
DryFilmThicknessofNonconductiveCoatingsAppliedto
5. Apparatus
a Nonferrous Metal Base
5.1 TestPanels, of any smooth, planar material of a size that
D 3924 Specification for Standard Environment for Condi-
can be accommodated by the panel holder of the automatic
spray machine.
5.1.1 Whensteelpanelsareused,theyshouldbepreparedin
accordance with the appropriate method in Practice
These practices are under the jurisdiction of ASTM Committee D01 on Paint
and Related Coatings, Materials, and Applications and are the direct responsibility
D 609D 609.
of Subcommittee D01.23 on Physical Properties of Applied Paint Films.
5.2 AutomaticSprayMachine, equipped with a panel holder
Current edition approved Nov. 10, 1995. Published January 1996. Originally
and a mounting for a spray gun.The machine shall be designed
published as D 823 – 45 T. Last previous edition D 823 – 92a.
Annual Book of ASTM Standards, Vol 06.01. to move the panel holder at a uniform speed past the fixed gun
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
D 823 – 95 (2001)
NOTE 1—Some automatic spray machines provide additional features
mount, or designed to move the gun mount at a uniform speed
that can improve the uniformity of film preparation. Some examples are:
past the fixed panel holder. The panel holder or the gun mount
az-barpanelholder;indexingofthepanelholderatrightanglestothegun
traverse speed shall be adjustable from 7.5 to 30 m (25 to 100
ft)/min. Typical machines are shown in Fig. 1.
(a) Fixed Gun, Traveling Panel Machine (b) Fixed Panel, Traveling Gun Machine
(c) Fixed Panel Programmable Indexing Traveling Gun Machine
FIG. 1 Automatic Spray Machines, Practice A
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
D 823 – 95 (2001)
to provide uniform lapping; and automatic control of number of passes,
8. Report
time between passes, and lapping distance.
8.1 Report the following information:
5.3 Spray Gun, any that will provide a uniform fan-type
8.1.1 Type of coating material,
spray pattern at least 150 mm (6 in.) in width is satisfactory.
8.1.2 Viscosity and percent of nonvolatile coating material,
The gun may be triggered manually or automatically.
8.1.3 Distance of test panel from gun tip,
5.4 Pressure Gage, covering the range of 0 to 690 kPa (0 to
8.1.4 Air pressure,
100 psi).
8.1.5 Number of spray passes,
5.5 Air Pressure Regulator.
8.1.6 Traverse speed,
5.6 Air Supply, oil-free, under pressure.
8.1.7 Temperature and relative humidity at time of applica-
tion, and
6. Preparation of Apparatus
8.1.8 Film thickness values obtained for applied coating.
6.1 Mount the spray gun on the automatic spray machine.
Connect the air line hose from the regulator to the air pressure
PRACTICE B—MOTOR-DRIVEN DIP COATER
gagewhichinturnisconnectedtotheairinletofthespraygun.
APPLICATION
6.2 Set the gun so that its tip is at the desired distance from
the test panel surface, usually in the range from 200 to 300 mm
9. Summary of Practice
( 8 to 12 in.).
9.1 Amotor-driven device is employed to withdraw the test
6.3 With the gun trigger fully open, adjust the air regulator
panel from a container of the coating material at a desired
to provide the desired reading on the air pressure gage.
uniform rate.
NOTE 2—A suitable air pressure is usually from 275 to 520 kPa (40 to
9.2 The thickness of coating applied is controlled by the
75 psi).
speed of panel withdrawal, the viscosity of the material, and
6.4 Set the automatic spray machine controls to provide the
the percent of solids in the material.
desired traverse speed of the panel holder or the gun mount,
whichever is pertinent to the type of machine being used.
10. Significance and Use
NOTE 3—Suitable traverse speeds for automative coatings usually
10.1 This test method is limited to those materials that flow
range from 17.5 to 22.5 m/min (700 to 900 in./min ).
out to smooth films when test panels are dipped into the
material and withdrawn.
7. Procedure
7.1 Strain the material to be sprayed into the container to be
11. Apparatus
used with the spray gun. Reduce the material to a viscosity
11.1 Dip Coater, consisting of a mechanism that will with-
suitable for spraying.
draw a panel from a container of the coating material at a
7.2 Connect the container to the gun and test the spray gun
predetermined rate. Suitable apparatus, is shown in Fig. 2(a)
operation while stationary, for correct spray pattern and uni-
and 2(b):
formity by allowing a momentary spray to be deposited on a
11.1.1 The apparatus shown in Fig. 2(a) uses a cord wound
piece of paper placed in the panel position. Adjust the air
around a step-cone pulley on the shaft of a motor to provide
pressure material flow, and spray fan width controls until the
panel withdrawal rate of 50, 75, and 100-mm (2, 3, and 4-in.
desired pattern and uniformity are obtained. Further refine-
)/min. Prior to withdrawal, the panel, attached to the cord, is
ments may be made in the spray pattern by modifying the air
lowered by hand into the container holding the material.
pressure, the type of thinning agent, and the consistency of the
11.1.2 The apparatus shown in Fig. 2(b) uses a cord driven
material.
by a variable-speed device that can provide panel immersion
NOTE 4—The width of the spray pattern should be considerably wider
and withdrawal rates that are continuously variable from65 to
than the width of the test panel to assure spray uniformity on the test
510 mm (2.5 to 20 in.)/min.
panel.
NOTE 5—Rectangularcontainers(F-stylecanwithlidcutoff)areuseful
7.3 Place a test panel on the panel holder and start the
because the smaller exposed surfaces of the liquid coating reduces volatile
machine. Operate the spray gun so that it will begin spraying a
loss.
few seconds before the test panel enters the spray pattern and
11.2 Test Panels, of any clean, smooth, rigid substrate of a
continue spraying a few seconds after the test panel leaves the
size that can be accommodated by the dip coater and the
spray pattern.
container.
7.4 Remove the coated panel and bake, force-dry, or air-dry
11.2.1 When steel panels are used they shall be prepared in
it, in accordance with its type, in a vertical position in a
accordance with the appropriate method in Methods
dust-free atmosphere, as described in Specification
D 609D 609.
D 3924D 3924.
7.5 Determine the thickness of the coating in accordance
NOTE 6—The test panels should not exceed 300 mm (12 in.) in length,
with Test Methods D 1005, D 1186, D 1212, or
but the width may be varied up to 300 mm (12 in.) if a suitable
D 1400D 1005D 1186D 1212D 1400, whichever is appropri-
counterweight is used and a dip tank of adequate size is provided. Use of
ate. a multiple hook will permit dipping several panels at one time.
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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D 823 – 95 (2001)
(a) Dip-Coater With Motor-Driven Step-Cone Pulley (b) Dip-Coater With Continuously Variable Speed Drive
FIG. 2 Dip-Coater, Practice B
12. Procedure 12.2.2 For the continuously variable speed apparatus set the
desired panel immersion and withdrawal rates on the control
12.1 Adjust the coating material to the proper percentage of
panel.
solids and viscosity. Measure the temperature of the material in
the container at the time of application. 12.3 Start the motor and withdraw the panel at the desired
rate, with a smooth movement entirely free of vibration. Bake,
NOTE 7—The operating conditions (viscosity, percent of nonvolatile
force-dry, or air-dry the coated panel, in accordance with its
matter, and rate of withdrawal) are specific for a given coating material
and film thickness and need to be determined by trial. Subsequent
type, in a vertical position in a dust-free atmosphere in
reproduction of the same operating conditions should give the same film
accordance with Specification D 3924D 3924.
thickness. Data are available on a variety of materials and film thickness
12.4 Determine the thickness of the coating in accordance
to indicate the range required. The viscosity range for normal film
with Test Methods D 1005, D 1186, or
thickness of13 to 50 mm ( 0.5 to 2.0 mil ) has been shown to be 1 to
2.5 P.
D 1400D 1005D 1186D 1400, whichever is appropriate.
12.2 Place the prepared test panel on the hook attached to 12.5 If the coating thickness is too low, coat another panel
the cord and lower it into the container holding the coating
using a slower rate of panel withdrawal. If the coating
material. Wind the cord once completely around the pulley of
thickness is too high, coat another panel using a faster rate of
the correct size to give the desired rate of withdrawal.
panel withdraw.
12.2.1 For the stepped-cone pulley apparatus, wind the cord
12.6 Continue in this manner until a test panel having the
once completely around the pulley of the correct size to give
desired film thickness is produced. Measure thickness on at
the desired weight of withdrawal.
least three different areas of the test panel to determine coating
uniformity.
NOTE 8—With the dip coater, non-uniform thickness on a panel is
Information covering viscosity, percent of solids, rates of withdrawal and film
frequently obtained. Hence, if the film thickness is greater at the bottom
thickness for a variety of finishing materials is given in the paper by Payne, H. F.,
than the top, the viscosity should be increased or the panel withdrawal
“The Dip Coater, An Instrument For Making Uniform Films by the Dip Method,”
Industrial and Engineering Chemistry, Analytical Edition, Vol 15, 1943, p. 48. speed should be reduced, or both.
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
D 823 – 95 (2001)
13. Report mechanism. The base plate shall hold paper charts flat by
means of a vacuum. The blade holder shall be designed to
13.1 Report the following information:
accommodatecommontypesofapplicatorbladesandtoaccept
13.1.1 Type of coating material,
weights for loading the applicator blade.Amechanism shall be
13.1.2 Viscosity, temperature, and percent nonvolatile of
provided to stop the blade movement automatically at the end
coating material,
of the draw-down. A suitable apparatus is shown in Fig. 3.
13.1.3 Rate of withdrawal,
16.2 Vacuum Source, a vacuum pump or a water aspirator.
13.1.4 Air temperature and relative humidity at time of
16.3 Applicator Blade, any common type, either with ad-
application, and
FIG. 3 Blade Film Applicator, Motor-Driven, Practice C
13.1.5 Mean and range of dry film thickness values ob- justable or fixed clearances.
tained.
16.4 Test Panels, any clean, smooth, rigid substrate or may
be paper charts or similar materials.
PRACTICE C—MOTOR-DRIVEN BLADE FILM
APPLICATION
NOTE 9—Rigid panels shall be cleaned in an approved manner. Steel
panels shall be prepared in accordance with the appropriate method in
14. Summary of Practice
Practice D 609D 609.
14.1 Auniform film is produced by an appl
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