1、Designation: D4414 95 (Reapproved 2013)Standard Practice forMeasurement of Wet Film Thickness by Notch Gages1This standard is issued under the fixed designation D4414; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of las
2、t 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 practice describes the use of thin rigid metalnotched gages, also called step or comb gages, in the measure-ment of
3、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 methods
4、given in TestMethods D1212.1.3 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 flat su
5、bstrates 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 mil
6、s ). 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 all of
7、 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:2D1212 Test Methods for M
8、easurement 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 lengths, i
9、spushed 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 gage
10、 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 not we
11、tted 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 are ap
12、plied 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 coating a
13、s 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.1This practice is under the jurisdiction of
14、ASTM Committee D01 on Paint andRelated Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.23 on Physical Properties of Applied Paint Films.Current edition approved July 1, 2013. Published July 2013. Originally approvedin 1984. Last previous edition approved in
15、2007 as D4414 95 (2007). DOI:10.1520/D4414-95R13.2For 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 AS
16、TM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.3 Measurement of wet film thickness at the time ofapplication is most appropriate as it permits correction andadjustment of the film by the applicator at the time ofapplication. Correction of the
17、film after it has dried orchemically cured requires costly extra labor time, may lead tocontamination of the film, and may introduce problems ofadhesion and integrity of the coating system.4.4 The procedures using notched gages do not provide asaccurate or sensitive measurements of wet film thicknes
18、s as dothe Interchemical and Pfund gages described in Test MethodsD1212. 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-ma
19、te thickness of wet 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 t
20、o ensure theminimum 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. Repo
21、rt5.1 Report the 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 onm
22、ethods of film application, 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 i
23、ntervals of the gages 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 distorteda
24、nd may exhibit greater 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, t
25、he tabs on one row of a gage maydiffer in length as follows:By 13 m (0.5 mil) between 0 to 150m(0and6mils),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
26、to a rigid substrate 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 a
27、rea sufficiently 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 o
28、ther end tab 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
29、each reading 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 varie
30、s with theshape 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, l
31、ook at both 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.3These g
32、ages are commercially available from various coating equipment andinstrument suppliers.FIG. 1 Rectangular Notched GageD4414 95 (2013)28.8 Determine the mean and range of the readings.9. Report9.1 Report the mean and range of the readings.PROCEDURE B10. Apparatus10.1 Circular Notched Gage,4thin metal
33、 disk, with 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
34、 50m increments 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 suffic
35、iently large 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
36、finger in 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
37、 reading bywiping 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
38、. Keywords13.1 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
39、patent rights, 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
40、either for 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 fa
41、ir hearing 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 st
42、andard may 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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).4The “
43、Hotcake” Wet Film Thickness Gage is covered by a patent held by PaulN. Gardner, Sr., 316 N.E. First Street, Pompano Beach, 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 GageD4414 95 (2013)3
