1、Designation: D 4414 95 (Reapproved 2007)Standard Practice forMeasurement of Wet Film Thickness by Notch Gages1This standard is issued under the fixed designation D 4414; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of l
2、ast revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice describes the use of thin rigid metalnotched gages, also called step or comb gages, in the measure-ment
3、of wet film thickness of organic coatings, such as paint,varnish, and lacquer.1.2 Notched gage measurements are neither accurate norsensitive, but they are useful in determining approximate wetfilm thickness of coatings on articles where size(s) and shape(s)prohibit the use of the more precise metho
4、ds given in TestMethods D 1212.1.3 This practice is divided into the following two proce-dures:1.3.1 Procedure AA square or rectangular rigid metalgage with notched sides is used to measure wet film thick-nesses ranging from 3 to 2000 m (0.5 to 80 mils 1). Such agage is applicable to coatings on fla
5、t substrates and to coatingson articles of various sizes and complex shapes where it ispossible to get the end tabs of the gage to rest in the same planeon the substrate.1.3.2 Procedure BAcircular thin rigid metal notched gageis used to measure wet film thicknesses ranging from 25 to2500 m (1 to 100
6、 mils ). Such a gage is applicable to coatingson flat substrates and to coatings on objects of various sizes andcomplex shapes.1.4 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.5 This standard does not purport to address al
7、l 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:2D 1212 Test Methods
8、for Measurement of Wet Film Thick-ness of Organic Coatings3. Summary of Practice3.1 The material is applied to the articles to be coated andthe wet film thickness measured with a notched gage.3.2 Procedure AA square or rectangular thin rigid metalgage with notched sides, having tabs of varying lengt
9、hs, ispushed perpendicularly into the film. After removal from thefilm, the gage is examined and the film thickness is determinedto lie between the clearance of the shortest tab wet by the filmand the clearance of the next shorter tab not wetted by the film.3.3 Procedure BA circular thin rigid metal
10、 gage havingspaced notches of varying depths around its periphery is rolledperpendicularly across the film. After removal from the film,the gage is examined and the film thickness is determined asbeing between the clearance of the deepest face wetted and theclearance of the next deepest notch face n
11、ot wetted by the film.4. Significance and Use4.1 Wet film thickness measurements of coatings applied onarticles can be very helpful in controlling the thickness of thefinal dry coating, although in some specifications the wet filmthickness is specified. Most protective and high performancecoatings a
12、re applied to meet a requirement or specification fordry film thickness for each coat or for the completed coatingsystem, or for both.4.2 There is a direct relationship between dry film thicknessand wet film thickness. The wet film/dry film ratio is deter-mined by the volume of volatiles in the coat
13、ing as applied,including permitted thinning. With some flat coatings the dryfilm thickness is higher than that calculated from the wet filmthickness. Consequently, the results from the notch gage arenot to be used to verify the nonvolatile content of a coating.4.3 Measurement of wet film thickness a
14、t the time ofapplication is most appropriate as it permits correction andadjustment of the film by the applicator at the time ofapplication. Correction of the film after it has dried orchemically cured requires costly extra labor time, may lead tocontamination of the film, and may introduce problems
15、 ofadhesion and integrity of the coating system.4.4 The procedures using notched gages do not provide asaccurate or sensitive measurements of wet film thickness as dothe Interchemical and Pfund gages described in Test Methods1This practice is under the jurisdiction of ASTM Committee D01 on Paint and
16、Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.23 on Physical Properties of Applied Paint Films.Current edition approved June 1, 2007. Published June 2007. Originallyapproved in 1984. Last previous edition approved in 2001 as D 4414 01 (2001).2For r
17、eferenced 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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700,
18、West Conshohocken, PA 19428-2959, United States.D 1212. Notch gages may, however, be used on nonuniformsurfaces, like concrete block, that are too rough to use theInterchemical and Pfund gages. Also notched gages can bevery useful in the shop and field for determining the approxi-mate thickness of w
19、et films over commercial articles wheresize(s) and shape(s) are not suitable for measurements by othertypes of gages. Examples of such items are ellipses, thin edges,and corners.4.5 An operator experienced in the use of a notched gagecan monitor the coating application well enough to ensure theminim
20、um required film thickness will be obtained.4.6 Application losses, such as overspray, loss on transfer,and coating residue in application equipment, are a significantunmeasurable part of the coating used on a job and are notaccounted for by measurement of wet film thickness.5. Report5.1 Report the
21、following information:5.1.1 The mean and range of the readings taken and thenumber of readings.5.1.2 The smallest graduation of the gage used.6. Precision and Bias6.1 The precision and bias of Procedure A or B for measur-ing wet film thickness with notch gages are very dependent onmethods of film ap
22、plication, time that the measurement is takenafter film application, mechanical condition of the notch gages,and the step range of the gages.6.2 Generally, the agreement between notch gages is goodbecause they are insensitive to small differences in filmthickness, that is the step intervals of the g
23、ages are relativelylarge.PROCEDURE A7. Apparatus7.1 Notched Gage, square or rectangular, thin rigid metalplate, with notched sides (see Fig. 1), made from steel oraluminum3(Note 1). Nonmetallic gages shall not be used.NOTE 1Aluminum or aluminum alloy gages are more easily distortedand may exhibit gr
24、eater wear than steel gages. Gages made of plastic ordeformable metal are not suitable.7.1.1 Each notched side shall consist of a series of tabs(between notches) varying in length and located in a linebetween two end tabs equal in length and longest in the row.7.1.2 As an example, the tabs on one ro
25、w of a gage maydiffer in length as follows:By 13 m ( 0.5 mil) between 0 to 150 m (0 and 6 mils),By 25 m (1 mil) between 150 to 250 m (6 and 10 mils),By 50 m (2 mils) between 250 to 750 m (10 and 30 mils),andBy 125 m(5 mils) over 750 m (30 mils).8. Procedure8.1 Apply the coating material to a rigid s
26、ubstrate and testwith the gage immediately. The gage must be used immediatelyfollowing application of the coating. Some coatings losesolvents quickly and spray application increases the speed. Theresulting rapid reduction in wet film thickness can causemisleading readings.8.2 Locate an area sufficie
27、ntly large to permit both end tabsof the gage to rest on the substrate in the same plane.8.3 Push the gage perpendicularly into the wet film so thatthe two end tabs rest firmly on the substrate at the same time.8.4 Or, set one end tab firmly on the substrate and lower thegage until the other end tab
28、 is firmly in contact with thesubstrate.8.5 Remove the gage from the film and examine the tabs.The film thickness is determined as being between the clear-ance of the shortest tab wetted and the clearance of the nextshorter tab not wetted by the film.8.6 Clean the gage immediately after each reading
29、 bywiping it on a dry or solvent-dampened cloth so that subse-quent readings are not affected. Do not clean with metalscrapers.8.7 Repeat the procedure in 8.2-8.5 for at least threelocations on the film. The number of readings required toobtain a good estimate of the film thickness varies with thesh
30、ape and size of the article being coated, with the operatorsexperience, and whether one or more of the following prob-lems are encountered:8.7.1 Some coatings may not wet (leave residue on) somemetal gages. However, the film itself may show where contactwas made. When reading the gage, look at both
31、the gage andthe film itself for verification of the reading.8.7.2 The gage may slip on the surface. Ignore such read-ings.8.7.3 The surface may be coarse and false readings pro-duced. The spot where the gage is used must be as uniform aspossible and questionable readings ignored.8.8 Determine the me
32、an and range of the readings.3These gages are commercially available from various coating equipment andinstrument suppliers.FIG. 1 Rectangular Notched GageD 4414 95 (2007)29. Report9.1 Report the mean and range of the readings.PROCEDURE B10. Apparatus10.1 Circular Notched Gage,4thin metal disk, with
33、 cali-brated notches of various depths spaced around its periphery(see Fig. 2). Each notch has a recessed flat face.Ahole is in thecenter of the disk.10.2 Examples of the scale increments and ranges providedby the notches are:10.2.1 25m increments between 25 m to 100 m (1 to 4mils),10.2.2 50m increm
34、ents between 150 m to 1500 m (6and 60 mils), and10.2.3 100m increments between 1500 m to 2000 m(60 and 80 mils ).11. Procedure11.1 Select a gage that has a segment with a thickness scaleappropriate for the expected range of wet-film thickness.11.2 Locate areas on the rigid substrate sufficiently lar
35、ge topermit the gage to roll for at least 112 in. (40 mm).11.3 Apply the liquid coating to the substrate and immedi-ately place the selected segment perpendicularly on the wetfilm and in firm contact with the substrate. Roll the gage acrossthe film, holding the disk with a thumb and index finger in
36、thecenter hole.11.4 Remove the gage from the film and inspect the notchfaces. The wet-film thickness is determined as being betweenthe clearance of the deepest notch face wetted and theclearance of the next deeper notch face not wetted by the film.11.5 Clean the gage immediately after each reading b
37、ywiping on a dry or solvent-dampened cloth so that subsequentreadings are not affected. Do not clean with metal scrapers.11.6 Repeat the procedure from 11.1-11.5 as described in8.7.11.7 Determine the mean and range of the readings.12. Report12.1 Report the mean and range of the readings.13. Keywords
38、13.1 circular notched gage; rectangular notched gageASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rig
39、hts, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for
40、 revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing
41、 you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may
42、 be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).4The “Hotcake” Wet Film Thickness Gage is covered by a patent held by PaulN. Gardner, Sr., 316 N.E. First Street, Pompano Beach,
43、FL 33060. Interested partiesare invited to submit information regarding the identification of acceptable alterna-tives to this patented item to the Committee on Standards, ASTM InternationalHeadquarters, 100 Barr Harbor Drive., West Conshohocken, PA 19428. Yourcomments will receive careful consideration at a meeting of the responsibletechnical committee, which you may attend.FIG. 2 Circular Notched GageD 4414 95 (2007)3
