ASTM D2967-02a

Standard Test Method for Corner Coverage of Powder Coatings

SCOPE
1.1 This test method covers the determination of the ratio of corner thickness (see ) to face thickness (see 3.1.3) of powdered plastic coatings applied to a specific face thickness by dipping preheated square bars into aerated powder and curing the coating using predetermined conditions.
Note 1—The property of corner coverage has also been referred to as "edge coverage," though the latter is not recommended. There are widespread misunderstandings and expectations relative to the term "edge coverage." This test is performed on a steel bar having square corners and the results do not necessarily relate to edges that are sharper, that is, burrs. A coating that has measurable corner coverage may still not protect sharper edges from corrosion or provide the electrical insulation needed in some applications.
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: 09-Dec-2002
• ICS: 29.035.99 - Other insulating materials
• Technical Committee: D01 - Paint and Related Coatings, Materials, and Applications
• Drafting Committee: D01.51 - Powder Coatings

Relations

• Replaces: ASTM D2967-02 - Standard Test Method for Edge Coverage of Powder Coatings
• Effective Date: 10-Dec-2002
• Replaced By: ASTM D2967-07 - Standard Test Method for Corner Coverage of Powder Coatings
• Effective Date: 01-Jun-2007
• Referred By: ASTM A1124/A1124M-23 - Standard Specification for Textured Epoxy-Coated Steel Reinforcing Bars
• Effective Date: 10-Dec-2002
• Referred By: ASTM D1711-22 - Standard Terminology Relating to Electrical Insulation
• Effective Date: 10-Dec-2002
• Referred By: ASTM A775/A775M-22 - Standard Specification for Epoxy-Coated Steel Reinforcing Bars
• Effective Date: 10-Dec-2002
• Referred By: ASTM D3451-06(2017) - Standard Guide for Testing Coating Powders and Powder Coatings
• Effective Date: 10-Dec-2002
• Referred By: ASTM D4242-07(2017) - Standard Test Method for Inclined Plate Flow for Thermosetting Coating Powders
• Effective Date: 10-Dec-2002
• Referred By: ASTM D3963/D3963M-21 - Standard Specification for Fabrication and Jobsite Handling of Epoxy-Coated Steel Reinforcing Bars
• Effective Date: 10-Dec-2002

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D2967–02a
Standard Test Method for
1
Corner Coverage of Powder Coatings
This standard is issued under the fixed designation D 2967; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope * such as spraying, sprinkling, or dipping. Usually hot parts are
used. Heat causes the powder to melt and flow into a dense
1.1 This test method covers the determination of the ratio of
coating.
corner thickness (see 3.1.3) to face thickness (see 3.1.4) of
3.1.2 corner coverage, n—of powder coating, the ratio of
powdered plastic coatings applied to a specific face thickness
the corner thickness to the face thickness of the fused coating
by dipping preheated square bars into aerated powder and
expressed in percent.
curing the coating using predetermined conditions.
3.1.3 corner thickness, n—of powder coating, the average
NOTE 1—The property of corner coverage has also been referred to as
thickness of the coating on sharp 90° corners of steel bars
“edge coverage,” though the latter is not recommended. There are
measured at 45° to the flat surfaces.
widespread misunderstandings and expectations relative to the term “edge
3.1.4 face thickness, n—of powder coating, the average
coverage.” This test is performed on a steel bar having square corners and
thickness of the coating on flat surfaces of steel bars measured
the results do not necessarily relate to edges that are sharper, that is, burrs.
A coating that has measurable corner coverage may still not protect perpendicular to the surfaces.
sharper edges from corrosion or provide the electrical insulation needed in
3.1.5 powder coatings, n—coatings which are protective or
some applications.
decorative, or both, formed by the application of a coating
powder to a substrate and fused in a continuous film by the
1.2 The values stated in SI units are to be regarded as the
application of heat or radiant energy.
standard. The values given in parentheses are for information
only.
4. Significance and Use
1.3 This standard does not purport to address all of the
4.1 This test method measures the degree to which different
safety concerns, if any, associated with its use. It is the
coating powder materials cover sharp corners. Corner coverage
responsibility of the user of this standard to establish appro-
is influenced by face thickness, thixotropy, melt viscosity,
priate safety and health practices and determine the applica-
surface tension, cure rate, and temperature of application and
bility of regulatory limitations prior to use.
curing.
2. Referenced Documents
5. Apparatus
2.1 ASTM Standards:
5.1 Aerated Bed—Suitable for providing a uniformly sus-
D 374 Test Methods for Thickness of Solid Electrical Insu-
2
pended dense phase of free–moving powder. Fig. 1 shows a
lation
schematic of an aerated bed used for suspending the coating
3. Terminology
powder.The equipment consists of an open top chamber which
has a porous plate for a false bottom. Air is introduced under
3.1 Definitions:
the plate at a low pressure so that it filters through the porous
3.1.1 coating powders, n— finely divided particles of resin,
plate and uniformly suspends the particles contained in the
either thermoplastic or thermosetting, generally incorporating
chamber.
pigments, fillers, and additives and remaining finely divided
5.2 Micrometer Caliper—25.4 mm (1 in.), in accordance
during storage under suitable conditions, which, after fusing
with Method C of Test Methods D 374.
and possibly curing, give a continuous film.
5.3 Oven, with forced convection capable of maintaining
3.1.1.1 Discussion—The coating powder may contain fill-
the specified temperature within 63°C.
ers,colorants,curingagents,etc.,consistentwithproducingthe
1 1
5.4 Test Bars, four, measuring 13 by 13 by 100 mm ( ⁄2by ⁄2
desired coatings. The powder is applied by various methods
by 4 in.) in accordance with Fig. 2.
5.4.1 Use bars that are free of rust and dirt, and which have
1
This test method is under the jurisdiction of ASTM Committee D01 on Paint
been washed with a clean solvent to remove any traces of oily
and Related Coatings, Materials, andApplications and is the direct responsibility of
substances. Bars may be reused if the coating used in a
Subcommittee D01.51 on Powder Coatings.
previoustesthasbeencompletelyremovedwithoutmarringthe
Current edition approved Dec. 10, 2002. Published February 2003. Originally
approved in 1971. Last previous edition approved in 2002 as D 2967 – 02.
2
Annual Book of ASTM Standards, Vol 10.01.
*A Summary of Changes section appears at the end of this standard.
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