ASTM_D_5235_-_18.pdf

Designation:D523518Standard Test Method forMicroscopic Measurement of Dry Film Thickness ofCoatings on Wood Products1This standard is issued under the fixed designation D5235;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 covers the measurement of dry filmthickness of coatings applied to a smooth,textured or curvedrigid substrate of wood or a wood-based product.1.2 This test method covers the preparation of wood orwood-based specimens for the purpose of microscopic mea-surement of dry film thickness.1.3 This test method suggests an analysis of dry filmthickness of coatings on wood or wood-based products using amicroscopic measurement.1.4 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard.The values stated ineach system may not be exact equivalents;therefore,eachsystem shall be used independently of the other.Combiningvalues from the two systems may result in non-conformancewith the standard.1.5 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.1.6 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:2E177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 dry film thickness or DFT,nthe thickness of dried,cured coating film on the substrate surface which may includeattached fibers but excludes free fibers that are encapsulated inthe layer itself.3.1.2 edge face,nthat part of the specimen that is a planeperpendicular to the surface showing a cross section of thecoating and substrate.3.1.3 soak in,nrefers to a coating on a porous(wood)where the coating does not lie essentially on the surface of thewood or wood-based product,but has penetrated into the fiberstructure of the wood or wood-based material.3.1.3.1 DiscussionWood or wood-based products are gen-erally of a porous nature;sometimes exhibiting uniformabsorption of coatings.Frequently absorption of coatings is ofa non-uniform nature and influenced by localized surfacedensity differences or wood pore size.These conditions ofcoating absorption are commonly referred to as soak in.4.Summary of Test Method4.1 A specimen of coated wood or wood-based product iscut to convenient size and edge face with the coating filmcross-section is prepared by polishing or cutting with a sharpblade.4.2 The prepared edge of the specimen is imaged by acalibrated imaging system with known magnification in orderto measure the dry film thickness using an image analysiscomputer program.4.3 Suggestions regarding interpretation of dry film thick-ness on porous wood or wood-based material are offered.5.Significance and Use5.1 As a base for calibration adjustment or accuracy verifi-cation of dry film coating thickness measuring instruments.5.2 The dry film thickness of coatings on wood or wood-based products is specified in written product warranties for1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.52 on Factory Coated Wood Products.Current edition approved Jan.15,2018.Published June 2018.Originallyapproved in 1992.Last previous edition approved in 2014 as D5235 14.DOI:10.1520/D5235-18.2For 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.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 proper decorative and protective performance of coatings onwood or wood-based products.5.3 The minimum and maximum dry film thickness ofcoatings is recommended by coating companies for satisfactorydecorat