ASTM_D_1212_-_91_2013.pdf

Designation:D121291(Reapproved 2013)Standard Test Methods forMeasurement of Wet Film Thickness of Organic Coatings1This standard is issued under the fixed designation D1212;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 These test methods cover the determination of wet filmthickness of organic coatings such as paint,varnish,andlacquer.Two methods are described as follows:1.1.1 In Test Method A,the Wet Film Thickness Gage(English or Metric graduation(see 5.1)is used to measure wetfilm thicknesses up to 60 mils on the English scale series,andup to 700 m on the metric scale series(Sections 5 8).1.1.2 In Test Method B,the Pfund Gage is used to measurewet film thicknesses up to 14.2 mils(360 m)(Sections 9 13).1.2 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.1.3 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 and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D823 Practices for Producing Films of Uniform Thicknessof Paint,Varnish,and Related Products on Test Panels3.Summary of Test Methods3.1 The material is applied in the laboratory to plane,rigidtest panels or in the field to the surface being coated.The wetfilm thickness is determined as quickly as possible to reduceshrinkage due to solvent loss.3.2 In Test Method A,a gage with one eccentric and twoconcentric wheels is rolled over the surface and the point wherethe eccentric wheel first touches the wet film is determined.3.3 In Test Method B,a gage with a convex lower surface ispushed into the wet film until the center touches the substrate.The diameter of the spot of wet coating left on the convexsurface is measured and the film thickness calculated from thediameter of the spot and the radius of curvature.4.Significance and Use4.1 Wet film thickness measurements aid in the predictionof dry film thickness.In instances where dry film thicknesscannot be measured nondestructively,wet film thickness isfrequently specified.Also,the ability to determine wet filmthickness during application can provide the opportunity tocorrect the application procedures.TEST METHOD A5.Apparatus5.1 Wet Film Thickness GageTwo versions of the gage arenow in use:3The original design as shown in Fig.1 and a laterdesign as shown in Fig.2.Both designs consists of an eccentriccenter wheel supported by two concentric wheels so as toprovide two scales that are bilaterally symmetrical.As the gageis rolled on the film,there is a change in clearance between thewet film and the eccentric wheel.The point at which the filmfirst touches the center wheel measures the thickness of thefilm.5.2 The later design shown in Fig.2,moves the eccentricwheel from between the concentric wheels,as shown in Fig.1,to the outside of the gage and closer to one of the concentricwheels.Gage reading errors of parallax across the gage areeliminated as the two scales are placed directly on the eccentricwheel and errors when measuring on uneven support surfacesare reduced by placing the eccentric wheel closer to one of thesupporting concentric wheels.5.3 Best precision is obtained when using the near linearcentral portion of each scale,constituting about 80%of its1These test methods are under the jurisdiction of ASTM Committee D01 onPaint and Related Coatings,Materials,and Applications and are the directresponsibility of Subcommittee D01.23 on Physical Properties of Applied PaintFilms.Current edition approved July 1,2013.Published July 2013.Originally approvedin 1952.Last previous edition approved in 2007 as D1212 91(2007)1.DOI:10.1520/D1212-91R13.2For 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.3Both versions of this gage(Interchemical(INMONT)and Model“C”)arecovered by U.S.Patents 2 507 592 and 3 128 558 and are issued to Maynard R.Euverard.Interested parties are invited to submit information regarding theidentification of acceptable alternatives to this patented item to the Committee onStandards,ASTM Headquarters.Your comments will receive careful considerationat a meeting of the responsible technical committee,which you may attend.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 total range as shown in the diagram in Fig.1 and Fig.2.Therefore,the range of the particular gage selected for useshould be such that the measured film thicknes