ASTM D6958-20

Standard Test Methods for Evaluating Side-Bonding Potential of Wood Coatings

SIGNIFICANCE AND USE
4.1 This test method was originally designed as a means of quantitatively measuring the level of adhesion of the wood-wood interface caused by a wood coatings system applied to the substrate. The tensile test is useful in measuring bonding strength of coatings, such as gymnasium coatings, in which the wood strip flooring primarily expands or contracts in response to changes across the cross-sectional width of the strip floor.  
4.2 This test method was further designed as a means of measuring the side-bonding potential of wood coating systems.
SCOPE
1.1 These test methods describe an evaluation procedure for the determination of undesirable side-bonding of coatings for wood flooring. They provide two mechanical properties tests for the quantitative determination of the cohesive strength of wood coatings (tensile and lap shear).  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Sep-2020
• ICS: 79.080 - Semi-manufactures of timber
• Technical Committee: D07 - Wood
• Drafting Committee: D07.01 - Fundamental Test Methods and Properties

Relations

• Refers: ASTM E4-14 - Standard Practices for Force Verification of Testing Machines
• Effective Date: 01-Jun-2014
• Refers: ASTM D9-12 - Standard Terminology Relating to Wood and Wood-Based Products
• Effective Date: 15-Oct-2012
• Refers: ASTM D2370-98(2010) - Standard Test Method for Tensile Properties of Organic Coatings
• Effective Date: 01-Dec-2010
• Refers: ASTM E4-10 - Standard Practices for Force Verification of Testing Machines
• Effective Date: 01-Jun-2010
• Refers: ASTM D9-09ae1 - Standard Terminology Relating to Wood and Wood-Based Products
• Effective Date: 15-Nov-2009
• Refers: ASTM D9-09a - Standard Terminology Relating to Wood and Wood-Based Products
• Effective Date: 15-Nov-2009
• Refers: ASTM E4-09a - Standard Practices for Force Verification of Testing Machines
• Effective Date: 01-Nov-2009
• Refers: ASTM D9-09 - Standard Terminology Relating to Wood and Wood-Based Products
• Effective Date: 01-May-2009
• Refers: ASTM E4-09 - Standard Practices for Force Verification of Testing Machines
• Effective Date: 01-Apr-2009
• Refers: ASTM E4-08 - Standard Practices for Force Verification of Testing Machines
• Effective Date: 01-Dec-2008
• Refers: ASTM D7438-08 - Standard Practice for Field Calibration and Application of Hand-Held Moisture Meters
• Effective Date: 01-Apr-2008
• Refers: ASTM E4-07 - Standard Practices for Force Verification of Testing Machines
• Effective Date: 01-Jan-2007
• Refers: ASTM D9-05 - Standard Terminology Relating to Wood and Wood-Based Products
• Effective Date: 01-Dec-2005
• Refers: ASTM E4-03 - Standard Practices for Force Verification of Testing Machines
• Effective Date: 10-Aug-2003
• Refers: ASTM E4-02 - Standard Practices for Force Verification of Testing Machines
• Effective Date: 10-Nov-2002

Overview

ASTM D6958-20: Standard Test Methods for Evaluating Side-Bonding Potential of Wood Coatings is an internationally recognized guideline developed by ASTM International. This standard provides test methods to quantitatively and qualitatively determine the side-bonding potential and cohesive strength of wood flooring coatings. Side-bonding is an undesirable effect where wood floor strips or panels adhere along their edges due to certain finishing systems, leading to panelization and potential flooring failures.

The intent of ASTM D6958-20 is to help manufacturers, flooring installers, and specifiers assess the risk of side-bonding caused by various wood coating systems. These methods are crucial in ensuring flooring products maintain performance, longevity, and visual integrity under real-world climate and use conditions.

Key Topics

• Side-Bonding and Panelization: Definitions and significance of side-bonding, panelization, and associated wood failures in finished wood flooring.
• Test Methods:
  • Tensile Strength Test (Maple Block Test): Quantifies the adhesive strength between wood substrates caused by the coating system.
  • Lap Shear Test (Maple Strip Test): Measures bonding strength for coatings, especially those used for parquet and other flooring with longitudinal movement.
  • Floor Simulation Test: A qualitative procedure to visually assess side-bonding and its effects under varying climate conditions.
• Terminology: Consistent usage of industry terms for clarity and accuracy in results.
• Laboratory and Conditioning Protocols: Procedures for specimen preparation, conditioning, curing, and measurement, ensuring reliable comparison and reproducibility.
• Reporting: Detailed documentation of test conditions, results, observations, and deviations.
• Health, Safety, and Environmental Considerations: Guidance on safe laboratory practices while applying these test methods.

Applications

The ASTM D6958-20 standard is applied extensively in the following areas:

• Wood Coating Product Development: Enables coating manufacturers to evaluate the side-bonding potential of new formulations, ensuring their products minimize adverse flooring issues.
• Quality Assurance for Wood Flooring Installations: Flooring professionals and contractors use these methods to vet coatings and finishes for gymnasiums, commercial spaces, and residential wood floors, ensuring compliance with industry best practices.
• Troubleshooting and Failure Analysis: Helps in diagnosing side-bonding or panelization failures in installed floors, guiding decisions on remedial actions.
• Specification and Procurement: Architects and specifiers refer to ASTM D6958-20 when selecting floor coating systems, ensuring materials deliver reliable performance across humidity and temperature variations.
• Compliance with Industry Standards: Maintains alignment with international trade and production standards, supporting cross-border flooring material use and acceptance.

Related Standards

For comprehensive wood flooring quality and performance, the following standards are commonly referenced alongside ASTM D6958-20:

• ASTM D9: Terminology Relating to Wood and Wood-Based Products
• ASTM D2370: Test Method for Tensile Properties of Organic Coatings
• ASTM D7438: Practice for Field Calibration and Application of Hand-Held Moisture Meters
• ASTM E4: Practices for Force Verification of Testing Machines
• British Standard BS 1204: Synthetic Resin Adhesives Test Method
• MFMA Guidelines: Maple Flooring Manufacturers Association guides for wood floor installation and grading
• NWFA Publications: National Wood Flooring Association manuals for troubleshooting, installation, and best practices

Practical Value

By following ASTM D6958-20, industry stakeholders gain:

• Objective evaluation of wood coating systems for risk of side-bonding and panelization.
• Data-driven decisions to prevent flooring defects, safeguarding installations and reducing costs from failure remediation.
• Compatibility with international best practices and regulatory frameworks, supporting global wood flooring trade and installation.

Keywords: side-bonding, wood coatings, panelization, tensile strength, lap shear strength, flooring finishes, ASTM D6958-20, wood flooring quality, adhesive failure, wood failure, coating evaluation, performance testing.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D6958 − 20
Standard Test Methods for
Evaluating Side-Bonding Potential of Wood Coatings
This standard is issued under the fixed designation D6958; 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.
1. Scope 2.3 National Wood Flooring Association (NWFA):
Technical Publication C200 Problems, Causes, and Cures
1.1 These test methods describe an evaluation procedure for
the determination of undesirable side-bonding of coatings for
3. Terminology
wood flooring. They provide two mechanical properties tests
for the quantitative determination of the cohesive strength of
3.1 Definitions—For general definitions of terms related to
wood coatings (tensile and lap shear).
wood, refer to Terminology D9.
1.2 The values stated in inch-pound units are to be regarded
3.2 Definitions of Terms Specific to This Standard:
as standard. The values given in parentheses are mathematical
3.2.1 panelization—condition caused by side-bonding, ex-
conversions to SI units that are provided for information only
cessive installation adhesive, substrate movement, or other
and are not considered standard.
factors where localized gaps develop between flooring strips
1.3 This standard does not purport to address all of the
while adjacent boards remain in tight contact acting as a
safety concerns, if any, associated with its use. It is the
composite panel instead of individual strips.
responsibility of the user of this standard to establish appro-
3.2.2 panelization failure—conditionwherelocalizedexces-
priate safety, health, and environmental practices and deter-
sive gaps beyond specified limits develop between some strip
mine the applicability of regulatory limitations prior to use.
flooring boards due to panelization.
1.4 This international standard was developed in accor-
3.2.3 percent wood failure—rupturing of wood fibers in
dance with internationally recognized principles on standard-
strength tests on bonded specimens usually expressed as the
ization established in the Decision on Principles for the
percentage of total area involved which shows such failure and
Development of International Standards, Guides and Recom-
is the inverse of adhesive failure.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
3.2.4 side-bonding—bonding of adjacent strips of wood
flooring caused by the floor coating resulting in panelization.
2. Referenced Documents
2 3.2.4.1 Discussion—Side-bonding is most commonly
2.1 ASTM Standards:
caused when installed wood flooring boards have become
D9 Terminology Relating to Wood and Wood-Based Prod-
adhered to each other. Finish materials, especially water-based
ucts
products, that have seeped between the boards, and the glue
D2370 Test Method for Tensile Properties of Organic Coat-
used on the flooring tongue-and-groove joint are two common
ings
sources of side-bonding. Side-bonding wood failure can occur
D7438 Practice for Field Calibration and Application of
as side-bonded flooring boards shrink due to loss of moisture
Hand-Held Moisture Meters
after installation.
E4 Practices for Force Verification of Testing Machines
2.2 Maple Flooring Manufacturers Association (MFMA): 3.2.5 side-bonding wood failure—failureofthewoodwithin
Grading Rules for MFMA Hard Maple a strip, as in classic wood failure, when the movement of the
strip within the floor is restrained from moisture-related
These test methods are under the jurisdiction of ASTM Committee D07 on movement by side-bonding and the resulting stress overcomes
Wood and are the direct responsibility of Subcommittee D07.01 on Fundamental
thetensilestrengthperpendiculartothegrainofthewoodstrip.
Test Methods and Properties.
Current edition approved Oct. 1, 2020. Published October 2020. Originally
3.2.6 tensile stress (nominal)—as used in Test Method
approved in 2003. Last previous edition approved in 2014 as D6958 – 03 (2014).
D2370,theloadperoriginalunitareaatwhichaspecimenfails
DOI: 10.1520/D6958-20.
or yields in a tension (pull) test.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
Available from the Maple Flooring Manufacturers Association, Inc. (MFMA), Available from the National Wood Flooring Association (NWFA), 111 Ches-
1425 Tri State Parkway, Suite 110, Gurnee, IL 60031, http://www.maplefloor.org. terfield Industrial Boulevard, Chesterfield, MO 63005, http://www.nwfa.org
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6958 − 20
TEST METHOD A—MAPLE BLOCK TENSILE
STRENGTH TEST
4. Significance and Use
4.1 This test method was originally designed as a means of
quantitatively measuring the level of adhesion of the wood-
wood interface caused by a wood coatings system applied to
the substrate. The tensile test is useful in measuring bonding
strength of coatings, such as gymnasium coatings, in which the
wood strip flooring primarily expands or contracts in response
to changes across the cross-sectional width of the strip floor.
4.2 This test method was further designed as a means of
measuring the side-bonding potential of wood coating systems.
5. Apparatus
5.1 Tensile Tester, of the constant rate of jaw separation
type, equipped with load cells having capacities of 100 to 1000
lb (445 to 4452 N), a data acquisition device capable of
capturingthepeakload,andsuitablysizedgripstoholdthetest
specimens in place during testing. The machine must be
capable of maintaining a cross head velocity during testing of
0.1 in./min (2.54 mm/min).The load cells shall be calibrated to
FIG. 1 Test Method A, Maple Block Tensile Strength Test—Test
an accuracy of at least 61 % in accordance with Practice E4.
Block
5.2 Clamp Assembly, capable of holding assembled test
specimen and maintaining a clamp pressure of 100 psi (690
6.5 Test assemblies consist of two test blocks “edge-glued”
kPa) during curing.
using the floor coating as an adhesive (see Fig. 1). The coating
to be evaluated shall be applied using a polybrush to the
5.3 Moisture Meter, meeting the requirements of Practice
smooth edge of both test blocks at a rate of 500 65ft /gal
D7438.
(12.3 6 0.1 m /L) or as specified by the coating manufacturer.
5.4 Foam Polybrushes, 1 in. (25.4 mm) wide.
After a 5-min open time the test block pairs shall be assembled
by placing the coated surfaces together and clamping the joint
6. Procedure
at 100 psi (690 kPa) pressure. Test assemblies shall remain
6.1 Material for testing shall be “Second and Better,”
clamped for a minimum of 48 h.
“MFMA-PQ” grade certified hard maple (Acer saccharum)
parquet flooring as specified in the Maple Flooring Manufac- 6.6 Test assemblies shall be cured at 75 6 5 °F (24 6 3 °C)
and 50 6 2 % relative humidity for a minimum of seven days
turers Association Parquet Flooring Grading Rules. These
rectangular, edge-grained strips shall have a planed finish and including the clamp time.After curing, use a moisture meter to
7 7
determine the moisture content of all test assemblies in
be ⁄8 6 0.03 in. (22.2 6 0.8 mm) in width by ⁄16 6 0.01 in.
accordance with Practice D7438, and calculate the average
(11.1 6 0.3 mm) in thickness. The segments chosen for testing
shall be clear wood that is as straight-grained and free from moisture content. Alternative curing conditions shall be per-
mitted provided that they are reported.
visual defects as possible. Unless required to satisfy the test
objectives and reported, adherence tests shall be conducted
6.7 Measure and record the length and width of the test
using factory-planed surfaces that are representative of typical
assembly to the nearest 0.01 in. (0.3 mm). Calculate the test
field conditions.
area of each test assembly.
6.2 Blocks for testing shall be cut to a length of 1.25 6 0.01
6.8 Test assemblies shall be secured in a test machine using
in. (31.8 6 0.3 mm).
grips that include either a universal joint on each end or a
6.3 Test blocks shall be conditioned at 75 6 5 °F (24 6 means to adjust the grips to ensure that the direction of applied
3 °C) and 50 6 2 % relative humidity for a minimum of seven force is perpendicular to the adhered surface (see Fig. 2). They
days. These conditions are intended to produce at least a shall be pulled apart in tension at a rate of 0.1 in./min (2.54
surface equilibration moisture content of ~9 % (see X1.3). mm/min).
After conditioning, use a moisture meter to determine the
6.9 Record the ultimate (peak) load, ultimate tensile stress,
moisture content of all test blocks in accordance with Practice
location of failure (coating-coating interface, coating-wood
D7438, then calculate and report the average moisture content.
interface, within wood), an estimate of the percent wood
Alternative conditioning environments shall be permitted pro-
failure, and the average moisture content.
vided that they are reported.
7. Report
6.4 A minimum of 20 test blocks shall be used to prepare a
minimum of ten assemblies for testing of each coating to be 7.1 Report the number of samples tested, any deviations
evaluated (see Fig. 1). from the default conditioning or curing conditions, the location
D6958 − 20
9.2 This test method was further designed as a means of
measuring the side-bonding potential of wood coating systems.
10. Apparatus
10.1 Tensile Tester, of the constant rate of jaw separation
type, equipped with load cells having capacities of 100 to 1000
lb (445 to 4452 N), a data acquisition device capable of
capturingthepeakload,andsuitablysizedgripstoholdthetest
specimens in place during testing. The machine must be
capable of maintaining
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D6958 − 03 (Reapproved 2014) D6958 − 20
Standard Test Methods for
Evaluating Side-Bonding Potential of Wood Coatings
This standard is issued under the fixed designation D6958; 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.
1. Scope
1.1 These test methods describe an evaluation procedure for the determination of undesirable side-bonding of coatings for wood
flooring. They provide two mechanical properties tests for the quantitative determination of the cohesive strength of wood coatings
(tensile and lap shear); they also provide a wood floor simulation test for the qualitative determination of side-bonding potential
of wood coatings.shear).
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard.
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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D9 Terminology Relating to Wood and Wood-Based Products
D2370 Test Method for Tensile Properties of Organic Coatings
D4444D7438 Test Method for Laboratory Standardization and CalibrationPractice for Field Calibration and Application of
Hand-Held Moisture Meters
E4 Practices for Force Verification of Testing Machines
2.2 British Standards:
B.S. 1204 British Standard Test for Synthetic Resin Adhesives
These test methods are under the jurisdiction of ASTM Committee D07 on Wood and are the direct responsibility of Subcommittee D07.01 on Fundamental Test Methods
and Properties.
Current edition approved Aug. 1, 2014Oct. 1, 2020. Published August 2014October 2020. Originally approved in 2003. Last previous edition approved in 20092014 as
D6958 – 03 (2009).(2014). DOI: 10.1520/D6958-03R14.10.1520/D6958-20.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6958 − 20
2.2 Maple Flooring Manufacturers Association (MFMA):
Guide Specification for Double Plywood Floor System Grading Rules for MFMA Hard Maple
Guide Specification for Sleeper and Sleeper with Plywood Floor Systems
2.4 Wood Flooring Manufacturers Association (NOFMA):
Cracks in Hardwood Floors
2.3 National Wood Flooring Association (NWFA):
Hardwood Floors Trouble Shooting ManualTechnical Publication C200 Problems, Causes, and Cures
3. Terminology
3.1 Definitions—For general definitions of terms related to wood, refer to Terminology D9.
3.2 Definitions:Definitions of Terms Specific to This Standard:
3.1.1 Definitions used in these test methods are in accordance with terminology used in Terminology D9. A few related terms not
covered in these test methods are as follows:
3.2.1 panelization—adjacent boards condition caused by side-bonding, excessive installation adhesive, substrate movement, or
other factors where localized gaps develop between flooring strips while adjacent boards remain in tight contact acting as a
composite panel instead of individual strips when subjected to changes in temperature and humidity as well as other site
conditions.strips.
3.2.2 panelization failure—the condition where localized excessive gaps beyond specified limits develop between some strip
flooring boards due to panelization.
3.2.3 percent wood failure—the rupturing of wood fibers in strength tests on bonded specimens usually expressed as the
percentage of total area involved,involved which shows such failure. The failure and is the inverse of adhesive failure.
3.2.4 side-bonding—the bonding of adjacent strips of wood flooring caused by the floor coating resulting in panelization. This is
one possible cause of panelization failure.
3.2.4.1 Discussion—
Side-bonding is most commonly caused when installed wood flooring boards have become adhered to each other. Finish materials,
especially water-based products, that have seeped between the boards, and the glue used on the flooring tongue-and-groove joint
are two common sources of side-bonding. Side-bonding wood failure can occur as side-bonded flooring boards shrink due to loss
of moisture after installation.
3.2.5 side-bonding wood failure—the failure of the wood within a strip, as in classic wood failure, when the movement of the strip
within the floor is restrained from moisture-related movement by excessive side-bonding. In this situation, the toughness or
“work-to-break” of the side-bonding is sufficient to overcome the side-bonding and the resulting stress overcomes the tensile
strength perpendicular to the grain of the wood strip.
3.2.6 tensile stress (nominal)—as used in Test Method D2370, the load per original unit area at which a specimen fails or yields
in a tension (pull) test.
SECTION I—MECHANICAL PROPERTIES TESTS
TEST METHOD A—MAPLE BLOCK TENSILE STRENGTH TEST
4. Significance and Use
4.1 This test method was originally designed as a means of quantitatively measuring the level of adhesion of the wood-wood
Available from British Standards Institute (BSI), 389 Chiswick High Rd., London W4 4AL, U.K., http://www.bsi-global.com.
Available from the Maple Flooring Manufacturers Association, Inc. (MFMA), 111 Deer Lake Road, Suite 100, Deerfield, IL 60015,1425 Tri State Parkway, Suite 110,
Gurnee, IL 60031, http://www.maplefloor.org.
Available from the National Wood Flooring Association (NWFA), 111 Chesterfield Industrial Boulevard, Chesterfield, MO 63005, http://www.woodfloors.orghttp://
www.nwfa.org
D6958 − 20
interface caused by a wood coatings system applied to the substrate. The tensile test is useful in measuring bonding strength of
coatings, such as gymnasium coatings, in which the wood strip flooring primarily expands or contracts in response to changes
across the cross-sectional width of the strip floor.
4.2 This test method was further designed as a means of measuring the side-bonding potential of wood coating systems.
5. Apparatus
5.1 Tensile Tester, of the constant rate of jaw separation type, equipped with load cells having capacities of 100 to 1000 lb (445
to 4452 N), and equipped with an indicating device such as an electronic constant speed chart recorder, a digital device that
displays numerical values, or a printer that records the numerical valuesa data acquisition device capable of capturing the peak
load, and suitably sized grips to hold the test specimens in place during testing. The machine must be capable of maintaining a
cross head velocity during testing of 0.1 in./min (2.54 mm/min), and if using a strip chart recorder, a chart speed during testing
of 10 in./min (254 mm/min).mm/min). The load cells shall be calibrated to an accuracy of at least 61 % in accordance with
Practice E4.
5.2 Clamp Assembly, capable of holding assembled test specimen and maintaining a clamp pressure of 100 psi (690 kPa).kPa)
during curing.
5.3 Moisture Meter, meeting the requirements of Test Method Practice D4444D7438.
5.4 Foam Polybrushes, 1 in. (25.4 mm) wide.
6. Procedure
6.1 Material for testing shall be #2 or better, MFMA “Second and Better,” “MFMA-PQ” grade certified hard maple (Acer
saccharum) tongue parquet flooring as specified in the Maple Flooring Manufacturers Association Parquet Flooring Grading
Rules.and groove strip flooring, 2 These rectangular, edge-grained strips shall have a planed finish and be ⁄8 6 0.03 in. (57.2(22.2
6 0.8 mm) in width by ⁄16 6 0.01 in. (19.8(11.1 6 0.3 mm) in thickness. The segments chosen for testing shall be clear wood
that is as straight-grained and free from visual defects as possible. Unless required to satisfy the test objectives and reported,
adherence tests shall be conducted using factory-planed surfaces that are representative of typical field conditions.
6.2 Test stock shall be prepared by cutting off the tongue and planing the edge smooth. Blocks for testing shall be cut to a length
of 3.001.25 6 0.01 in. (76.2(31.8 6 0.3 mm).
6.3 Test blocks shall be conditioned at 75 6 5°F5 °F (24 6 3°C)3 °C) and 50 6 2 % relative humidity for a minimum of seven
days. These conditions equate to an are intended to produce at least a surface equilibration moisture content (EMC) of ~9 % (see
X1.3). After equilibrating,conditioning, use a moisture meter to determine the EMC moisture content of all test blocks, blocks in
accordance with Practice D7438, then calculate and report the average EMC.moisture content. Alternative conditioning
environments shall be permitted provided that they are reported.
6.4 A minimum of twenty20 test blocks shall be used to prepare a minimum of ten assemblies for testing of each coating to be
evaluated (see Fig. 1).
6.5 Test assemblies consist of two test blocks “edge-glued” using the floor coating as an adhesive (see Fig. 1). The coating to be
2 2
evaluated shall be applied using a polybrush to the smooth edge of both test blocks at a rate of 500 6 5 ft /gal (12.3 6 0.1 m /L)
or as specified by the coating manufacturer. After a 5 min 5-min open time the test block pairs shall be assembled by placing the
coated surfaces together and clamping the joint at 100 psi (690 kPa) pressure. Test assemblies shall remain clamped for a minimum
of 48 h.
6.6 Test assemblies shall be cured at 75 6 5°F5 °F (24 6 3°C)3 °C) and 50 6 2 % relative humidity for a minimum of seven days
including the clamp time. After equilibrating,curing, use a moisture meter to determine the EMC moisture content of all test
assemblies, assemblies in accordance with Practice D7438, and calculate the average EMC.moisture content. Alternative curing
conditions shall be permitted provided that they are reported.
D6958 − 20
FIG. 1 Test Method A, Maple Block Tensile Strength Test-Test Blocks (top), Test Assembly (bottom)Test—Test Block
6.7 Measure and record the length and width of the test assembly to the nearest 0.01 in. (0.3 mm). Calculate the test area of each
test assembly.
6.8 Test assemblies shall be secured in a test machine using grips that include either a universal joint on each end or a means to
adjust the grips to ensure that the direction of applied force is perpendicular to the adhered surface (see Fig. 2) and ). They shall
be pulled apart in tension at a rate of 0.1 in./min (2.54 mm/min).
6.9 Record the ultimate load, (peak) load, ultimate tensile stress, location of failure (coating-coating interface, coating-wood
interface, within wood), an estimate of the percent wood failure, and the average EMC.moisture content.
7. Report
7.1 Report the number of samples tested, the any deviations from the default conditioning or curing conditions, the location of
failure (coating-coating interface, coating-wood interface, within wood), an estimate of the percent wood failure, the average
moisture content, and the average EMC.ultimate tensile strength as load and stress.
8. Precision and Bias
8.1 Until sufficient data are available as a result of performing these tests, no specific precision and bias statement can be
expressed.
TEST METHOD B—MAPLE STRIP LAP SHEAR TEST
9. Significance and Use
9.1 This test method was originally designed as a means of quantitatively measuring the level of adhesion of the wood-wood bond
interface caused by a wood coatings system applied to the substrate. The lap shear test is useful for measuring bonding strength
of coatings used on parquet or other similar types of flooring, where longitudinal movement of the flooring is a concern (for
example, the shear force as the individual wood pieces slide past each other).
9.2 This test method was further designed as a means of measuring the side-bonding potential of wood coating systems.
D6958 − 20
FIG. 2 Assembly Secured in Testing Machine
10. Apparatus
10.1 Tensile Tester, of the constant rate of jaw separation type, equipped with load cells having capacities of 100 to 1000 lb (445
to 4452 N), and equipped with an indicating device such as an electronic constant speed chart recorder, a digital device that
displays numerical values, or a printer that records the numerical values as well as a data acquisition device capable of capturing
the peak load, and suitably sized grips to hold the test specimens in place during testing. The machine must be capable of
maintaining a cross head velocity during testing of 0.1 in./min (2.54 mm/min), and if using a strip chart recorder a chart speed
during testing of 10 in./min (254 mm/min).mm/min). The load cells shall be calibrated to an accuracy of at least 61 % in
accordance with Practice E4.
10.2 Clamp Assembly, capable of holding assembled test specimen and maintaining a clamp pressure of 100 psi (690 kPa).kPa)
during curing.
10.3 Moisture Meter, meeting the requirements of Test Method Practice D4444D7438.
10.4 Foam Polybrushes, 1 in. (25.4 mm) wide.
11. Procedure
11.1 Source material for testing shall be “Second and Better” grade, Maple Flooring Manufacturers Association certified hard
1 25
maple (Acer saccharum) tongue-and-groove strip flooring, 2 ⁄4 6 0.03 in. (57.2 6 0.8 mm) in width by ⁄32 6 0.01 in. (19.8 6
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0.3 mm) in thickness. Alternatively, it shall be permitted to use ⁄4 in. (31.8 mm) quarter-sawn hard maple lumber planed to an
approximate thickness of 1 in. (25.4 mm) for the source material. Regardless of source material type:
11.1.1 The growth rings shall be permitted to be at any angle, from 0 to 90° inclusive, relative to the face.
11.1.2 The source material shall be chosen so that the resulting strips shall be flat and free from splits, knots, whorls, and decay,
that the angle of inclination of the grain across the face of each test strip shall be not greater than 1 in 9, and that the grain shall
not be obviously inclined to the face (see Appendix X2).
11.2 Test stock shall be prepared by cutting off the tongue and planing the edge smooth. Strips for testing shall be planed from
this test stock to a width of 1.0 6 0.01 in. (25.4 6 0.3 mm), a length of 4.5 6 0.01 in. (114 6 0.3 mm), and a thickness of 0.125
6 0.006 in. (3.18 6 0.15 mm). The face of the strip to be adhered should be planed; the opposing face that is not adhered shall
be permitted to be planed or smoothly sawn.
11.3 Test strips shall be conditioned at 75 6 5 °F (24 6 3 °C) and 50 6 2 % relative humidity for a minimum of seven days. These
conditions are intended to produce at least a surface moisture content of ~9 %. Alternative conditioning shall be permitted provided
that it is reported. After conditioning, use a moisture meter to determine the moisture content of all test strips in accordance with
Practice D7438, and calculate the average moisture content.
11.4 A minimum of 20 test strips shall be used to prepare a minimum of ten assemblies for testing of each coating to be evaluated
(see Fig. 3).
11.5 Material for testing shall be #2 Test assemblies consist of two test strips “face-glued” using the floor coating as an adhesive.
The coating to be evaluated shall be applied using a polybrush on a one-inch overlap test area on the ends of the test strips at a
2 2
rate of 150 6 5 ft /gal (3.7 6 0.1 m or better, MFMA certified hard maple (Acer saccharum)/L) or as specified by the coating
manufacturer (see Fig. 3tongue and groove strip flooring, 2). After a 5-min open time the test strip pairs shall be assembled by
FIG. 3 Test Method B, Maple Strip Lap Shear Test-TestTest—Test Strips (top), Test Assembly (bottom)
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placing the coated surfaces together and clamping the joint at ⁄4 6 0.03 in. (57.2 6 0.8 mm) in width by100 psi (690 kPa) pressure.
Test assemblies shall remain clamped ⁄32 6 0.01 in. (19.8 6 0.3for a minimum of 48 h (see Figs. 4 and 5mm) in thickness.).
11.1.1 Test stock shall be prepared by cutting off the tongue and planing the edge smooth. Strips for testing shall be planed from
this test stock to a width of 1.0 6 0.01 in. (25.4 6 0.3 mm), a length of 4.5 6 0.01 in. (114 6 0.3 mm) and a thickness, 0.125
6 0.006 in. (3.18 6 0.15 mm) (see Appendix X2).
11.1.2 Test strips shall be conditioned at 75 6 5°F (24 6 3°C) and 50 6 2 % relative humidity for a minimum of seven days.
These conditions equate to an EMC of ~9 % (see X1.3). After equilibrating, use a moisture meter to determine the EMC of all test
strips, and calculate the average EMC.
11.1.3 A minimum of twenty test strips shall be used to prepare a minimum of ten assemblies for testing of each coating to be
evalu
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