ASTM_D_6762_-_18.pdf

Designation:D676218Standard Test Method forDetermining the Hiding Power of Paint by Visual Evaluationof Spray Applied Coatings1This standard is issued under the fixed designation D6762;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method provides for the quantitative visualdetermination of the film thickness required to achieve fullhiding.This film thickness is considered to be the hiding powerof a test paint.1.2 This method applies only to spray applied coatings butits concepts are valid for other methods of application as well.1.3 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D16 Terminology for Paint,Related Coatings,Materials,andApplicationsD609 Practice for Preparation of Cold-Rolled Steel Panelsfor Testing Paint,Varnish,Conversion Coatings,andRelated Coating ProductsD1005 Test Method for Measurement of Dry-Film Thick-ness of Organic Coatings Using MicrometersD1729 Practice for Visual Appraisal of Colors and ColorDifferences of Diffusely-Illuminated Opaque MaterialsD1730 PracticesforPreparationof AluminumandAluminum-Alloy Surfaces for PaintingD2805 Test Method for Hiding Power of Paints by Reflec-tometryD7091 Practice for Nondestructive Measurement of DryFilm Thickness of Nonmagnetic Coatings Applied toFerrous Metals and Nonmagnetic,Nonconductive Coat-ings Applied to Non-Ferrous MetalsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 DefinitionsFor definitions of terms used in this testmethod,refer to Terminology D16 and the Paint/CoatingsDictionary.34.Summary of Test Method4.1 The test paint is applied by means of spray applicationin a wedge-shaped film over a black and white,black and grayor red and gray pattern so that a thickness variation is obtained,which provides excess hiding at one end of the pattern andpartial hiding at the other end of the pattern.4.2 The dry film is examined under standard illumination toselect the point where the pattern just becomes obscured.Thethickness of the film at this point is designated the hidingpower of the paint.5.Significance and Use5.1 This test method determines hiding power of a test paintby visual evaluation of a spray applied coating.NOTE1Test Method D2805 describes an instrumental method fordetermining hiding power.The paint film is applied at a uniform thickness(for example with a doctor blade),the film thickness is measuredrigorously,and the opacity is determined photometrically.Hiding power isthereby determined with a high degree of precision.5.2 Test Method D6762 is less precise than Test MethodD2805,but is commonly used since it is more closely related1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.26 on Optical Properties.Current edition approved Sept.1,2018.Published September 2018.Originallyapproved in 2002.Last previous edition approved in 2017 as D6762 02a(2017).DOI:10.1520/D6762-18.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Published by the Federation of Societies for Coatings Technology,492Norristown Rd.,Blue Bell,PA 19422.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 to the application characteristics of the paint and is simpler inconcept and evaluation.6.Apparatus6.1 Test Surface,a smooth-surfaced paper chart,approxi-mately 2 by