ASTM D823-95(2012)e1

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

• Status: Historical
• Publication Date: 31-Oct-2012
• ICS: 87.040 - Paints and varnishes
• Technical Committee: D01 - Paint and Related Coatings, Materials, and Applications
• Drafting Committee: D01.23 - Physical Properties of Applied Paint Films

Relations

• Replaced By: ASTM D823-17 - Standard Practices for Producing Films of Uniform Thickness of Paint, Varnish, and Related Products on Test Panels
• Effective Date: 01-Dec-2017

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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
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Designation: D823 − 95 (Reapproved 2012)
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 U.S. Department of Defense.
ε NOTE—Figure 3 was replaced and Section 18 was editorially corrected in November 2012.
1. Scope D1212 Test Methods for Measurement of Wet Film Thick-
ness of Organic Coatings
1.1 Five practices are given for preparing films of uniform
D1400 TestMethodforNondestructiveMeasurementofDry
thickness of coatings on test panels. These practices are:
Film Thickness of Nonconductive Coatings Applied to a
Practice A—Automatic Spray Machine Application
Nonferrous Metal Base (Withdrawn 2006)
Practice B—Motor-Driven Dip Coater Application
D3924 Specification for Environment for Conditioning and
Practice C—Motor-Driven Blade Film Application
Testing Paint, Varnish, Lacquer, and Related Materials
Practice D—Hand-Held Spray Gun Application
Practice E—Hand-Held Blade Film Application
PRACTICE A—AUTOMATIC SPRAY MACHINE
1.2 The values stated in SI units are to be regarded as the APPLICATION
standard. The values given in parentheses are for information
3. Summary of Practices
only.
3.1 A liquid material is applied to a test panel by means of
1.3 This standard does not purport to address all of the
an automatic spray machine consisting of a mounted spray gun
safety concerns, if any, associated with its use. It is the
and a panel holder. This machine can (1) move the panel
responsibility of the user of this standard to establish appro-
holder, with test panel, at a uniform speed through the
priate safety and health practices and determine the applica-
atomized spray produced by a fixed spray gun, or (2)itcan
bility of regulatory limitations prior to use.
move the gun, with atomized spray, at a uniform speed past the
test panel mounted on a fixed panel holder. A machine
2. Referenced Documents
equipped with a programmable system can index the spray gun
2.1 ASTM Standards:
vertically for multiple passes and for multiple coats with
D609 Practice for Preparation of Cold-Rolled Steel Panels
selective time delay.
for Testing Paint, Varnish, Conversion Coatings, and
3.2 The thickness of coating applied is controlled by the
Related Coating Products
traverse speed of the panel or gun, the fluid delivery rate of the
D1005 Test Method for Measurement of Dry-Film Thick-
gun, the viscosity of the material, and the amount of nonvola-
ness of Organic Coatings Using Micrometers
tile matter in the material.
D1186 Test Methods for Nondestructive Measurement of
Dry Film Thickness of Nonmagnetic Coatings Applied to
4. Significance and Use
a Ferrous Base (Withdrawn 2006)
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
These practices are under the jurisdiction of ASTM Committee D01 on Paint
evaluation of metallic coatings for appearance properties, such
and Related Coatings, Materials, and Applications and are the direct responsibility
as gloss and color.
of Subcommittee D01.23 on Physical Properties of Applied Paint Films.
Current edition approved Nov. 1, 2012. Published November 2012. Originally
4.2 Coatingsappliedbythistestmethodmayexhibitaslight
approved in 1945. Last previous edition approved in 2007 as D823 – 95 (2007).
orange-peel or spray wave.
DOI: 10.1520/D0823-95R12E01.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
5. Apparatus
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
5.1 TestPanels,ofanysmooth,planarmaterialofasizethat
the ASTM website.
can be accommodated by the panel holder of the automatic
The last approved version of this historical standard is referenced on
www.astm.org. spray machine.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D823 − 95 (2012)
5.1.1 Whensteelpanelsareused,theyshouldbepreparedin 7.3 Place a test panel on the panel holder and start the
accordance with the appropriate method in Practice D609. machine. Operate the spray gun so that it will begin spraying a
few seconds before the test panel enters the spray pattern and
5.2 AutomaticSprayMachine, equipped with a panel holder
continue spraying a few seconds after the test panel leaves the
and a mounting for a spray gun.The machine shall be designed
spray pattern.
to move the panel holder at a uniform speed past the fixed gun
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
with Test Methods D1005, D1186, D1212,or D1400, which-
NOTE 1—Some automatic spray machines provide additional features
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,
8.1.6 Traverse speed,
5.5 Air Pressure Regulator.
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
PRACTICE B—MOTOR-DRIVEN DIP COATER
6.1 Mount the spray gun on the automatic spray machine.
Connect the air line hose from the regulator to the air pressure APPLICATION
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).
6.4 Set the automatic spray machine controls to provide the
10. Significance and Use
desired traverse speed of the panel holder or the gun mount,
10.1 This test method is limited to those materials that flow
whichever is pertinent to the type of machine being used.
out to smooth films when test panels are dipped into the
NOTE3—Suitabletraversespeedsforautomativecoatingsusuallyrange
material and withdrawn.
from 17.5 to 22.5 m/min (700 to 900 in./min ).
11. Apparatus
7. Procedure
11.1 Dip Coater, consisting of a mechanism that will with-
7.1 Strain the material to be sprayed into the container to be
draw a panel from a container of the coating material at a
used with the spray gun. Reduce the material to a viscosity
predetermined rate. Suitable apparatus, is shown in Fig. 2(a)
suitable for spraying.
and 2(b):
7.2 Connect the container to the gun and test the spray gun 11.1.1 The apparatus shown in Fig. 2(a) uses a cord wound
operation while stationary, for correct spray pattern and uni- around a step-cone pulley on the shaft of a motor to provide
formity by allowing a momentary spray to be deposited on a panel withdrawal rate of 50, 75, and 100-mm (2, 3, and 4-in.
piece of paper placed in the panel position. Adjust the air )/min. Prior to withdrawal, the panel, attached to the cord, is
pressure material flow, and spray fan width controls until the lowered by hand into the container holding the material.
desired pattern and uniformity are obtained. Further refine- 11.1.2 The apparatus shown in Fig. 2(b) uses a cord driven
ments may be made in the spray pattern by modifying the air by a variable-speed device that can provide panel immersion
pressure, the type of thinning agent, and the consistency of the and withdrawal rates that are continuously variable from 65 to
material. 510 mm (2.5 to 20 in.)/min.
NOTE 4—The width of the spray pattern should be considerably wider NOTE 5—Rectangular containers (F-style can with lid cut off) are useful
than the width of the test panel to assure spray uniformity on the test because the smaller exposed surfaces of the liquid coating reduces volatile
panel. loss.
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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
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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
to indicate the range required. The viscosity range for normal film
11.2 Test Panels, of any clean, smooth, rigid substrate of a
thickness of 13 to 50 mm (0.5 to 2.0 mil ) has been shown to be 1 to 2.5
size that can be accommodated by the dip coater and the
P.
container.
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,
but the width may be varied up to 300 mm (12 in.) if a suitable
the correct size to give the desired rate of withdrawal.
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
12. Procedure
the desired weight of withdrawal.
12.1 Adjust the coating material to the proper percentage of 12.2.2 For the continuously variable speed apparatus set the
solidsandviscosity.Measurethetemperatureofthematerialin desired panel immersion and withdrawal rates on the control
the container at the time of application.
panel.
NOTE 7—The operating conditions (viscosity, percent of nonvolatile
12.3 Start the motor and withdraw the panel at the desired
matter, and rate of withdrawal) are specific for a given coating material
rate, with a smooth movement entirely free of vibration. Bake,
and film thickness and need to be determined by trial. Subsequent
force-dry, or air-dry the coated panel, in accordance with its
reproduction of the same operating conditions should give the same film
thickness. Data are available on a variety of materials and film thickness type, in a vertical position in a dust-free atmosphere in
accordance with Specification D3924.
Information covering viscosity, percent of solids, rates of withdrawal and film
12.4 Determine the thickness of the coating in accordance
thickness for a variety of finishing materials is given in the paper by Payne, H. F.,
with Test Methods D1005, D1186,or D1400, whichever is
“The Dip Coater, An Instrument For Making Uniform Films by the Dip Method,”
Industrial and Engineering Chemistry, Analytical Edition, Vol 15, 1943, p. 48. appropriate.
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D823 − 95 (2012)
12.5 If the coating thickness is too low, coat another panel non-rigid materials, such as paper charts. It is more reliable for
using a slower rate of panel withdrawal. If the coating producing uniform films than is the use of hand-held draw-
thickness is too high, coat another panel using a faster rate of down applicators.
panel withdraw.
16. Apparatus
12.6 Continue in this manner until a test panel having the
desired film thickness is produced. Measure thickness on at 16.1 Motor-Driven Blade Film Applicator, consisting of a
least three different areas of the test panel to determine coating base plate, a bar for holding an applicator blade, and a driving
uniformity. mechanism. The base plate shall hold paper charts flat by
means of a vacuum. The blade holder shall be designed to
NOTE 8—With the dip coater, non-uniform thickness on a panel is
accommodatecommontypesofapplicatorbladesandtoaccept
frequently obtained. Hence, if the film thickness is greater at the bottom
weights for loading the applicator blade.Amechanism shall be
than the top, the viscosity should be increased or the panel withdrawal
speed should be reduced, or both.
provided to stop the blade movement automatically at the end
of the draw-down. A suitable apparatus is shown in Fig. 3.
13. Report
16.2 Vacuum Source, a vacuum pump or a water aspirator.
13.1 Report the following information:
16.3 Applicator Blade, any common type, either with ad-
13.1.1 Type of coating material,
justable or fixed clearances.
13.1.2 Viscosity, temperature, and percent nonvolatile of
coating material,
16.4 Test Panels, any clean, smooth, rigid substrate or may
13.1.3 Rate of withdrawal,
be paper charts or similar materials.
13.1.4 Air temperature and relative humidity at time of
NOTE 9—Rigid panels shall be cleaned in an approved manner. Steel
application, and
panels shall be prepared in accordance with the appropriate method in
13.1.5 Mean and range of dry film thickness values ob-
Practice D609.
tained.
17. Procedure
PRACTICE C—MOTOR-DRIVEN BLADE FILM
17.1 Clean the base plate and place the test panel on it.
APPLICATION
17.2 If a vacuum is needed to hold the test panel flat,
14. Summary of Practice
connect the vacuum source t
...