ASTM D4138-07a(2017)

Standard Practices for Measurement of Dry Film Thickness of Protective Coating Systems by Destructive, Cross-Sectioning Means

SIGNIFICANCE AND USE
5.1 Many coating properties are markedly affected by the film thickness of the dry film such as adhesion, flexibility, and harness. To be able to compare results obtained by different operators, it is essential to measure film thickness carefully.  
5.2 Most protective and high performance coatings are applied to meet a requirement or a specification for the dry-film thickness of each coat, or for the complete system, or both. Coatings must be applied within a certain minimum and maximum thickness tolerances in order that they can fulfill their intended function.
SCOPE
1.1 This practice describes the measurement of dry film thickness of coating films by microscopic observation of precision angular cuts in the coating film. Use of these procedures may require repair of the coating film. This practice is intended to supplement the manufacturers' instructions for the manual operation of the gages and is not intended to replace them. It includes definitions of key terms, reference documents, the significance and use of the practice, and the advantages and limitations of the instruments.  
1.2 Three procedures are provided for measuring dry film thickness of protective coating systems:  
1.2.1 Procedure A—Using groove cutting instruments.  
1.2.2 Procedure B—Using grinding instruments.  
1.2.3 Procedure C—Using drill bit instruments.  
1.3 These procedures are not applicable for soft or ductile substrates that may deform under the test gage cutting tip. The substrate should be sufficiently rigid to prevent deformation of the coating during the cutting process. The surface may be flat or moderately curved. Pipes as small as 25 mm (1 in.) in diameter may be measured in the axial direction.  
1.4 Individual coats in a multicoat system where there is a discernible visual difference between coats or the overall thickness of a coating system can be measured by these procedures.  
1.5 The range of thickness measurement is typically 2 to 2000 microns (0.1 to 80 mils) and depends upon the cutting angle of the blade.  
1.6 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.  
1.7 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.  
1.8 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: Historical
• Publication Date: 30-Nov-2017
• 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

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: D4138 − 07a (Reapproved 2017)
Standard Practices for
Measurement of Dry Film Thickness of Protective Coating
1
Systems by Destructive, Cross-Sectioning Means
This standard is issued under the fixed designation D4138; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
1.1 This practice describes the measurement of dry film
1.8 This international standard was developed in accor-
thickness of coating films by microscopic observation of
dance with internationally recognized principles on standard-
precision angular cuts in the coating film. Use of these
ization established in the Decision on Principles for the
proceduresmayrequirerepairofthecoatingfilm.Thispractice
Development of International Standards, Guides and Recom-
is intended to supplement the manufacturers’ instructions for
mendations issued by the World Trade Organization Technical
themanualoperationofthegagesandisnotintendedtoreplace
Barriers to Trade (TBT) Committee.
them. It includes definitions of key terms, reference
documents, the significance and use of the practice, and the
2. Referenced Documents
advantages and limitations of the instruments.
2
2.1 ASTM Standards:
1.2 Three procedures are provided for measuring dry film
D823Practices for Producing Films of Uniform Thickness
thickness of protective coating systems:
of Paint, Varnish, and Related Products on Test Panels
1.2.1 Procedure A—Using groove cutting instruments.
D1005Test Method for Measurement of Dry-Film Thick-
1.2.2 Procedure B—Using grinding instruments.
ness of Organic Coatings Using Micrometers
1.2.3 Procedure C—Using drill bit instruments.
D7091Practice for Nondestructive Measurement of Dry
Film Thickness of Nonmagnetic Coatings Applied to
1.3 These procedures are not applicable for soft or ductile
Ferrous Metals and Nonmagnetic, Nonconductive Coat-
substrates that may deform under the test gage cutting tip. The
ings Applied to Non-Ferrous Metals
substrate should be sufficiently rigid to prevent deformation of
the coating during the cutting process. The surface may be flat
3. Terminology
or moderately curved. Pipes as small as 25 mm (1 in.) in
3.1 Definitions of Terms:
diameter may be measured in the axial direction.
3.1.1 accuracy, n—the measure of the magnitude of error
1.4 Individual coats in a multicoat system where there is a
between the result of a measurement and the true thickness of
discernible visual difference between coats or the overall
the item being measured.
thickness of a coating system can be measured by these
3.1.2 dry film thickness, n—the thickness of a coating (or
procedures.
coating layers) as measured from the surface of the substrate.
1.5 The range of thickness measurement is typically 2 to
3.1.3 micrometre (micron), n—one one-thousandths of a
2000 microns (0.1 to 80 mils) and depends upon the cutting
millimetre (0.001 mm); 25.4 microns = 1 mil.
angle of the blade.
3.1.4 mil, n—an imperial unit of measure; one one-
1.6 The values stated in SI units are to be regarded as the
thousandths of an inch (0.001 in.); 1 mil = 25.4 microns.
standard. The values given in parentheses are for information
3.1.5 reticle, n—a scale on transparent material fitted at the
only.
focal plane of the eyepiece of the microscope for the purpose
1.7 This standard does not purport to address all of the
of measuring the width of a feature within the image.
safety concerns, if any, associated with its use. It is the
4. Summary of Practice
responsibility of the user of this standard to establish appro-
4.1 The three procedures are based on measurement of dry
filmthicknessbyobservationofthewidthofangularcutsinthe
1
These practices are under the jurisdiction of ASTM Committee D01 on Paint
and Related Coatings, Materials, and Applications and are the direct responsibility
2
of Subcommittee D01.23 on Physical Properties of Applied Paint Films. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Dec. 1, 2017. Published December 2017. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1982. Last previous edition approved in 2013 as D4138–07a (2013). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/D4138-07AR17. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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D4138 − 07a (2017)
c
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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: D4138 − 07a (Reapproved 2013) D4138 − 07a (Reapproved 2017)
Standard Practices for
Measurement of Dry Film Thickness of Protective Coating
1
Systems by Destructive, Cross-Sectioning Means
This standard is issued under the fixed designation D4138; 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*Scope
1.1 This practice describes the measurement of dry film thickness of coating films by microscopic observation of precision
angular cuts in the coating film. Use of these procedures may require repair of the coating film. This practice is intended to
supplement the manufacturers’ instructions for the manual operation of the gages and is not intended to replace them. It includes
definitions of key terms, reference documents, the significance and use of the practice, and the advantages and limitations of the
instruments.
1.2 Three procedures are provided for measuring dry film thickness of protective coating systems:
1.2.1 Procedure A—Using groove cutting instruments.
1.2.2 Procedure B—Using grinding instruments.
1.2.3 Procedure C—Using drill bit instruments.
1.3 These procedures are not applicable for soft or ductile substrates that may deform under the test gage cutting tip. The
substrate should be sufficiently rigid to prevent deformation of the coating during the cutting process. The surface may be flat or
moderately curved. Pipes as small as 25 mm (1 in.) in diameter may be measured in the axial direction.
1.4 Individual coats in a multicoat system where there is a discernible visual difference between coats or the overall thickness
of a coating system can be measured by these procedures.
1.5 The range of thickness measurement is typically 2 to 2000 microns (0.1 to 80 mils) and depends upon the cutting angle of
the blade.
1.6 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.7 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.
1.8 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
2.1 ASTM Standards:
D823 Practices for Producing Films of Uniform Thickness of Paint, Varnish, and Related Products on Test Panels
D1005 Test Method for Measurement of Dry-Film Thickness of Organic Coatings Using Micrometers
D7091 Practice for Nondestructive Measurement of Dry Film Thickness of Nonmagnetic Coatings Applied to Ferrous Metals
and Nonmagnetic, Nonconductive Coatings Applied to Non-Ferrous Metals
3. Terminology
3.1 Definitions of Terms:
1
These practices are under the jurisdiction of ASTM Committee D01 on Paint and Related Coatings, Materials, and Applications and are the direct responsibility of
Subcommittee D01.23 on Physical Properties of Applied Paint Films.
Current edition approved July 1, 2013Dec. 1, 2017. Published July 2013December 2017. Originally approved in 1982. Last previous edition approved in 20072013 as
D4138 – 07a.D4138 – 07a (2013). DOI: 10.1520/D4138-07AR13.10.1520/D4138-07AR17.
2
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’sstandard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
D4138 − 07a (2017)
3.1.1 accuracy, n—the measure of the magnitude of error between the result of a measurement and the true thickness of the item
being measured.
3.1.2 dry film thickness, n—the thickness of a coating (or coating layers) as measured from the surface of the substrate.
3.1.3 micrometre (micron), n—one one-thousand
...