ASTM D823-95(2012)
(Practice)Standard Practices for Producing Films of Uniform Thickness of Paint, Varnish, and Related Products on Test Panels
Standard Practices for Producing Films of Uniform Thickness of Paint, Varnish, and Related Products on Test Panels
SIGNIFICANCE AND USE
4.1 These practices should be used for those coatings that are designed for spray applications of objects in the factory or in the field. It is particularly important that it be used in the evaluation of metallic coatings for appearance properties, such as gloss and color.
4.2 Coatings applied by this test method may exhibit a slight orange-peel or spray wave.
SCOPE
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 Application
Practice B—Motor-Driven Dip Coater Application
Practice C—Motor-Driven Blade Film Application
Practice D—Hand-Held Spray Gun Application
Practice E—Hand-Held Blade Film Application
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is 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.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D823 − 95 (Reapproved2012)
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 D823; 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 D1400 TestMethodforNondestructiveMeasurementofDry
Film Thickness of Nonconductive Coatings Applied to a
1.1 Five practices are given for preparing films of uniform
Nonferrous Metal Base (Withdrawn 2006)
thickness of coatings on test panels. These practices are:
D3924 Specification for Environment for Conditioning and
Practice A—Automatic Spray Machine Application
Testing Paint, Varnish, Lacquer, and Related Materials
Practice B—Motor-Driven Dip Coater Application
Practice C—Motor-Driven Blade Film Application
PRACTICE A—AUTOMATIC SPRAY MACHINE
Practice D—Hand-Held Spray Gun Application
APPLICATION
Practice E—Hand-Held Blade Film Application
1.2 The values stated in SI units are to be regarded as the 3. Summary of Practices
standard. The values given in parentheses are for information
3.1 A liquid material is applied to a test panel by means of
only.
an automatic spray machine consisting of a mounted spray gun
1.3 This standard does not purport to address all of the
and a panel holder. This machine can (1) move the panel
safety concerns, if any, associated with its use. It is the
holder, with test panel, at a uniform speed through the
responsibility of the user of this standard to establish appro-
atomized spray produced by a fixed spray gun, or (2)itcan
priate safety and health practices and determine the applica-
move the gun, with atomized spray, at a uniform speed past the
bility of regulatory limitations prior to use.
test panel mounted on a fixed panel holder. A machine
equipped with a programmable system can index the spray gun
2. Referenced Documents
vertically for multiple passes and for multiple coats with
selective time delay.
2.1 ASTM Standards:
D609 Practice for Preparation of Cold-Rolled Steel Panels
3.2 The thickness of coating applied is controlled by the
for Testing Paint, Varnish, Conversion Coatings, and
traverse speed of the panel or gun, the fluid delivery rate of the
Related Coating Products
gun, the viscosity of the material, and the amount of nonvola-
D1005 Test Method for Measurement of Dry-Film Thick-
tile matter in the material.
ness of Organic Coatings Using Micrometers
D1186 Test Methods for Nondestructive Measurement of
4. Significance and Use
Dry Film Thickness of Nonmagnetic Coatings Applied to
4.1 These practices should be used for those coatings that
a Ferrous Base (Withdrawn 2006)
are designed for spray applications of objects in the factory or
D1212 Test Methods for Measurement of Wet Film Thick-
in the field. It is particularly important that it be used in the
ness of Organic Coatings
evaluation of metallic coatings for appearance properties, such
as gloss and color.
These practices are under the jurisdiction of ASTM Committee D01 on Paint
4.2 Coatingsappliedbythistestmethodmayexhibitaslight
and Related Coatings, Materials, and Applications and are the direct responsibility
orange-peel or spray wave.
of Subcommittee D01.23 on Physical Properties of Applied Paint Films.
Current edition approved Nov. 1, 2012. Published November 2012. Originally
approved in 1945. Last previous edition approved in 2007 as D823 – 95 (2007).
5. Apparatus
DOI: 10.1520/D0823-95R12.
5.1 TestPanels,ofanysmooth,planarmaterialofasizethat
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
can be accommodated by the panel holder of the automatic
Standards volume information, refer to the standard’s Document Summary page on
spray machine.
the ASTM website.
5.1.1 Whensteelpanelsareused,theyshouldbepreparedin
The last approved version of this historical standard is referenced on
www.astm.org. accordance with the appropriate method in Practice D609.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D823 − 95 (2012)
5.2 AutomaticSprayMachine, equipped with a panel holder few seconds before the test panel enters the spray pattern and
and a mounting for a spray gun.The machine shall be designed continue spraying a few seconds after the test panel leaves the
to move the panel holder at a uniform speed past the fixed gun spray pattern.
mount, or designed to move the gun mount at a uniform speed
7.4 Remove the coated panel and bake, force-dry, or air-dry
past the fixed panel holder. The panel holder or the gun mount
it, in accordance with its type, in a vertical position in a
traverse speed shall be adjustable from 7.5 to 30 m (25 to 100
dust-free atmosphere, as described in Specification D3924.
ft)/min. Typical machines are shown in Fig. 1.
7.5 Determine the thickness of the coating in accordance
NOTE 1—Some automatic spray machines provide additional features
with Test Methods D1005, D1186, D1212,or D1400, which-
that can improve the uniformity of film preparation. Some examples are:
ever is appropriate.
az-barpanelholder;indexingofthepanelholderatrightanglestothegun
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,
8.1.7 Temperature and relative humidity at time of
5.6 Air Supply, oil-free, under pressure.
application, and
8.1.8 Film thickness values obtained for applied coating.
6. Preparation of Apparatus
6.1 Mount the spray gun on the automatic spray machine. PRACTICE B—MOTOR-DRIVEN DIP COATER
APPLICATION
Connect the air line hose from the regulator to the air pressure
gagewhichinturnisconnectedtotheairinletofthespraygun.
9. Summary of Practice
6.2 Set the gun so that its tip is at the desired distance from
9.1 Amotor-driven device is employed to withdraw the test
the test panel surface, usually in the range from 200 to 300 mm
panel from a container of the coating material at a desired
(8 to 12 in.).
uniform rate.
6.3 With the gun trigger fully open, adjust the air regulator
9.2 The thickness of coating applied is controlled by the
to provide the desired reading on the air pressure gage.
speed of panel withdrawal, the viscosity of the material, and
NOTE 2—A suitable air pressure is usually from 275 to 520 kPa (40 to
the percent of solids in the material.
75 psi).
10. Significance and Use
6.4 Set the automatic spray machine controls to provide the
10.1 This test method is limited to those materials that flow
desired traverse speed of the panel holder or the gun mount,
out to smooth films when test panels are dipped into the
whichever is pertinent to the type of machine being used.
material and withdrawn.
NOTE3—Suitabletraversespeedsforautomativecoatingsusuallyrange
from 17.5 to 22.5 m/min (700 to 900 in./min ).
11. Apparatus
11.1 Dip Coater, consisting of a mechanism that will with-
7. Procedure
draw a panel from a container of the coating material at a
7.1 Strain the material to be sprayed into the container to be
predetermined rate. Suitable apparatus, is shown in Fig. 2(a)
used with the spray gun. Reduce the material to a viscosity
and 2(b):
suitable for spraying.
11.1.1 The apparatus shown in Fig. 2(a) uses a cord wound
7.2 Connect the container to the gun and test the spray gun around a step-cone pulley on the shaft of a motor to provide
operation while stationary, for correct spray pattern and uni-
panel withdrawal rate of 50, 75, and 100-mm (2, 3, and 4-in.
formity by allowing a momentary spray to be deposited on a )/min. Prior to withdrawal, the panel, attached to the cord, is
piece of paper placed in the panel position. Adjust the air lowered by hand into the container holding the material.
pressure material flow, and spray fan width controls until the 11.1.2 The apparatus shown in Fig. 2(b) uses a cord driven
desired pattern and uniformity are obtained. Further refine- by a variable-speed device that can provide panel immersion
ments may be made in the spray pattern by modifying the air and withdrawal rates that are continuously variable from 65 to
pressure, the type of thinning agent, and the consistency of the 510 mm (2.5 to 20 in.)/min.
material.
NOTE 5—Rectangular containers (F-style can with lid cut off) are useful
because the smaller exposed surfaces of the liquid coating reduces volatile
NOTE 4—The width of the spray pattern should be considerably wider
loss.
than the width of the test panel to assure spray uniformity on the test
panel.
11.2 Test Panels, of any clean, smooth, rigid substrate of a
7.3 Place a test panel on the panel holder and start the size that can be accommodated by the dip coater and the
machine. Operate the spray gun so that it will begin spraying a container.
D823 − 95 (2012)
(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
D823 − 95 (2012)
(a) Dip-Coater With Motor-Driven Step-Cone Pulley (b) Dip-Coater With Continuously Variable Speed Drive
FIG. 2 Dip-Coater, Practice B
11.2.1 When steel panels are used they shall be prepared in 12.2 Place the prepared test panel on the hook attached to
accordance with the appropriate method in Practice D609. the cord and lower it into the container holding the coating
material. Wind the cord once completely around the pulley of
NOTE 6—The test panels should not exceed 300 mm (12 in.) in length,
the correct size to give the desired rate of withdrawal.
but the width may be varied up to 300 mm (12 in.) if a suitable
counterweight is used and a dip tank of adequate size is provided. Use of 12.2.1 For the stepped-cone pulley apparatus, wind the cord
a multiple hook will permit dipping several panels at one time.
once completely around the pulley of the correct size to give
the desired weight of withdrawal.
12. Procedure
12.2.2 For the continuously variable speed apparatus set the
12.1 Adjust the coating material to the proper percentage of
desired panel immersion and withdrawal rates on the control
solidsandviscosity.Measurethetemperatureofthematerialin
panel.
the container at the time of application.
12.3 Start the motor and withdraw the panel at the desired
NOTE 7—The operating conditions (viscosity, percent of nonvolatile
rate, with a smooth movement entirely free of vibration. Bake,
matter, and rate of withdrawal) are specific for a given coating material
force-dry, or air-dry the coated panel, in accordance with its
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 D3924.
thickness. Data are available on a variety of materials and film thickness
to indicate the range required. The viscosity range for normal film
12.4 Determine the thickness of the coating in accordance
thickness of 13 to 50 mm (0.5 to 2.0 mil ) has been shown to be 1 to 2.5
with Test Methods D1005, D1186,or D1400, whichever is
P.
appropriate.
12.5 If the coating thickness is too low, coat another panel
Information covering viscosity, percent of solids, rates of withdrawal and film
using a slower rate of panel withdrawal. If the coating
thickness for a variety of finishing materials is given in the paper by Payne, H. F.,
thickness is too high, coat another panel using a faster rate of
“The Dip Coater, An Instrument For Making Uniform Films by the Dip Method,”
Industrial and Engineering Chemistry, Analytical Edition, Vol 15, 1943, p. 48. panel withdraw.
D823 − 95 (2012)
FIG. 3 Blade Film Applicator, Motor-Driven, Practice C
12.6 Continue in this manner until a test panel having the non-rigid materials, such as paper charts. It is more reliable for
desired film thickness is produced. Measure thickness on at producing uniform films than is the use of hand-held draw-
least three different areas of the test panel to determine coating down applicators.
uniformity.
16. Apparatus
NOTE 8—With the dip coater, non-uniform thickness on a panel is
16.1 Motor-Driven Blade Film Applicator, consisting of a
frequently obtained. Hence, if the film thickness is greater at the bottom
than the top, the viscosity should be increased or the panel withdrawal
base plate, a bar for holding an applicator blade, and a driving
speed should be reduced, or both.
mechanism. The base plate shall hold paper charts flat by
means of a vacuum. The blade holder shall be designed to
13. Report
accommodatecommontypesofapplicatorbladesandtoaccept
13.1 Report the following information:
weights for loading the applicator blade.Amechanism shall be
13.1.1 Type of coating material,
provided to stop the blade movement automatically at the end
13.1.2 Viscosity, temperature, and percent nonvolatile of
of the draw-down. A suitable apparatus is shown in Fig. 3.
coating material,
16.2 Vacuum Source, a vacuum pump or a water aspirator.
13.1.3 Rate of withdrawal,
16.3 Applicator Blade, any common type, either with ad-
13.1.4 Air temperature and relative humidity at time of
justable or fixed clearances.
application, and
13.1.5 Mean and range of dry film thickness values ob-
16.4 Test Panels, any clean, smooth, rigid substrate or may
tained.
be paper charts or similar materials.
PRACTICE C—MOTOR-DRIVEN BLADE FILM NOTE 9—Rigid panels shall be cleaned in an approved manner. Steel
panels shall be prepared in accordance with the appropriate method in
APPLICATION
Practice D609.
14. Summary of Practice
17. Procedure
14.1 Auniform film is produced by an applicator blade that
17.1 Clean the base plate and place the test panel on it.
is pushed across the test panel at a uniform speed by a
17.2 If a vacuum is needed
...
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