1、Designation: C 419 08Standard Practice forMaking and Curing Test Specimens of Mastic ThermalInsulation Coatings1This standard is issued under the fixed designation C 419; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、last 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 covers the preparation of specimens ofmastics and coatings in the form of cured sheets or films thatmay
3、 be used in other procedures for evaluation of physicalproperties.1.2 Three procedures are described for casting and curing(Note 1) mastics and coatings of all types for thermal insula-tion.NOTE 1The term “cure” is used primarily to denote the condition thatdevelops as the result of loss of volatile
4、 matter but also to denote possiblesubsequent changes in chemical or physical properties due to crosslinking.1.2.1 Procedure A is intended to provide a specimen ofcontrolled thickness applied to insulation, and equivalent inother respects to that obtainable under field application condi-tions. The t
5、hermal insulation intended for field use may bespecified as the backing.1.2.2 Procedure B is intended to provide a free-filmspecimen of controlled thickness having smooth surfaces onboth sides. This type is required for some types of physicaltesting.1.2.3 Procedure C is intended to provide a free-fi
6、lmspecimen of controlled thickness having one smooth surface(as field applied).1.3 The procedures of this practice are not intended for theevaluation of application properties. These are covered in TestMethods C 461 and Guide C 647.1.4 The values stated in inch-pound units are to be regardedas stand
7、ard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered 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 sta
8、ndard 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:2C 168 Terminology Relating to Thermal InsulationC 461 Test Methods for Mastics and Coatings Used WithThermal InsulationC 533
9、Specification for Calcium Silicate Block and PipeThermal InsulationC 647 Guide to Properties and Tests of Mastics and CoatingFinishes for Thermal InsulationD6 Test Method for Loss on Heating of Oil and AsphalticCompounds3. Terminology3.1 DefinitionsFor definitions used in this practice seeTerminolog
10、y C 168.4. Summary of Practice4.1 Mastics and coatings are applied by a metal blade tothermal insulation backing material in a thickness regulated byguide bars. Moderate heat is applied to the specimens to dry orotherwise cure them.5. Significance and Use5.1 The method of preparation of test specime
11、ns of masticthermal insulation coatings can have an impact upon valuesobtained during testing. Testing laboratories should follow thispractice to help ensure the reproducibility of test methods forwhich a cured sheet or film of a mastic thermal insulationcoating is required.6. Apparatus6.1 Guide Bar
12、sTwo rectangular steel bars of thicknessequal to the desired wet thickness of the applied mastic orcoating. The guide bars shall be equal in length to the totallength of the specimens. For use on relatively soft backingmaterial, the guide bars may be equipped with pins projecting1This practice is un
13、der the jurisdiction of ASTM Committee C16 on ThermalInsulation and is the direct responsibility of Subcommittee C16.33 on InsulationFinishes and Moisture.Current edition approved May 1, 2008. Published May 2008. Originallyapproved in 1958. Last previous edition approved in 2000 as C 419 94 (2000).2
14、For 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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C
15、700, West Conshohocken, PA 19428-2959, United States.from the lower surface at each end, which can be forced intothe backing to hold the bars in position during preparation ofthe test specimen.6.2 Strike-Off Bar A flat strip of rigid metal, not less than2 in. (51 mm) greater in length than the width
16、 of the specimen.One edge shall be smooth and straight.6.3 Leveling Roller One section of straight 112-in. (38-mm) stainless steel pipe or any other convenient cylindricalleveling tool. The tool shall have a smooth surface. Minimumlength shall be 2 in. (51 mm) longer than the width of thespecimen.6.
17、4 Backing Material Unless otherwise specified by theprocedure for the test to be made, the backing for the specimenshall consist of commercial block-type calcium silicate insula-tion meeting the requirements of Specification C 533 andmeasuring 2 by 18 by 24 in. (51 by 457 by 610 mm). Thebacking bloc
18、k may be prepared by assembling not more thanthree blocks of smaller dimensions by the use of suitableadhesive or pins, in such a manner as to form a solid, rigidblock.6.5 Release PaperAsmooth, dense white paper coated onone side with dextrin, or other water-soluble gum. Size shouldbe approximately
19、the same as the backing block.NOTE 2Films coated with PTFE or other suitable nonsoluble releaseagent may be used as an acceptable alternative.7. Preparation of Test Specimens7.1 Stir the mastic or coating until uniform throughout thecontainer before removing the sample for specimen prepara-tion.7.2
20、Determine the percent volatile matter by weight inaccordance with Test Methods C 461, for use in calculating thedegree of cure in 8.1.2.7.3 Unless otherwise specified, lay down films to a nominalwet thickness of 0.125 in. (3.2 mm).7.4 Procedure A (Adhered Film)For the determination ofdegree of cure
21、as described in 8.1.2, prepare one extraspecimen in addition to the number required by the otherprocedures in which they are to be used. If a primer orpretreatment of the block is specified, apply to the testspecimen in accordance with the recommendations of themanufacturer of the mastic or coating.
22、 Place and secure guidebars of a thickness equal to the desired wet mastic thickness onthe backing material along each of the long edges. Fill the areabetween the guide bars with mastic and smooth out with atrowel to a level about 0.063 in. (1.6 mm) above the guide bars.Place the strike-off bar upon
23、 the guide bars at one end of thefilled area and move it slowly to the other end of the specimen,pushing the mastic along the surface of the backing. Asee-sawing motion of the strike-off bar will be found to aid inuniform distribution of the mastic. As the mastic is distributed,take care to prevent
24、inclusion of air pockets. Move thestrike-off bar from end to end of the specimen in bothdirections, removing the excess material and filling the depres-sions, until a coat of uniform thickness extending from end toend of the specimen covers the entire space between the guidebars. Remove the guide ba
25、rs without disturbing the wetspecimen.7.5 Procedure B (Free Film)For the determination ofdegree of cure as described in 8.1.2, prepare one extraspecimen in addition to the number required by the otherprocedures in which they are to be used. Place a sheet of therelease paper on the backing block so t
26、hat the coated surface ofthe paper faces upward, away from the backing block. Placeand secure guide bars of thickness equal to the desired wetmastic thickness on the release paper along each of the longedges. Fill the area between the guide bars with mastic andsmooth out with a trowel to a level abo
27、ut 0.063 in. (1.6 mm)above the guide bars. Place on the freshly applied masticanother sheet of release paper with the coated surface facingthe mastic, in the following manner: Place a short edge of thecoated paper at one end of the mastic-filled area and graduallyroll the paper into the wet mastic,
28、using the leveling roller.Take care to prevent formation of air pockets, or bubbles, underthe paper. When firmly in contact with the mastic, roll out thepaper-covered mastic until its thickness matches that of theguide bars. Then remove the guide bars without disturbing thethickness of the specimen
29、or the position of the paper. Aconvenient method for accomplishing this is to slit the paperwith a sharp blade along the inside length of the guide bars.7.6 Procedure C (Free Film)For the determination ofdegree of cure as described in 8.1.2, prepare one extraspecimen in addition to the number requir
30、ed by the otherprocedures in which they are to be used. Place a sheet of therelease paper on the backing block so that the coated surface ofthe paper faces upward, away from the backing block. Placeguide bars of thickness equal to the desired wet masticthickness on the release paper along each of th
31、e long edges. Fillthe area between the guide bars with mastic and smooth outwith a trowel to a level about 0.063 in. (1.6 mm) above theguide bars. Place the strike-off bar upon the guide bars at oneend of the filled area and move it slowly to the other end of thespecimen, pushing the mastic along th
32、e surface of the backing.A see-sawing motion of the strike-off bar will be found to aidin uniform distribution of the mastic. As the mastic is distrib-uted, take care to prevent inclusion of air pockets. Move thestrike-off bar from end to end of the specimen in bothdirections, removing the excess ma
33、terial and filling the depres-sions, until a coat of uniform thickness extending from end toend of the specimen covers the entire space between the guidebars. Remove the guide bars without disturbing the wetspecimen.7.7 When a reinforcing membrane is specified, apply themastic in two separate coats
34、of equal thickness unless other-wise specified. Immediately following the first coat press themembrane into the wet mastic. Then apply the second coat tothe required thickness.8. Curing Prepared Specimens8.1 Procedure A (Adhered Film):8.1.1 During the first 24-h hold the test specimens at 60 to80F (
35、15 to 27C). At the end of the 24-h period remove thespecimens to a thermostatically controlled oven having atemperature of 150 6 5F (63 to 68C) and hold in this ovenuntil the desired degree of cure has been reached.8.1.2 To determine the degree of cure, take from the extraspecimen a sample of the co
36、ating from an area typical of thatC419082to be subjected to test conditions during later procedures.Determine the percentage of volatile liquids evaporated fromthe mastic during the curing as follows: Weigha1to2-gsample to the nearest 0.001 g and place it for a period of5hat220 6 5F (104 6 3C) in an
37、 oven conforming to therequirements specified in Test Method D6. At the conclusionof the 5-h heating period, remove the sample from the oven,cool to room temperature, and weigh to the nearest 0.001 g.Calculate the loss in weight as a percent of the weight beforeheating. Calculate the degree of cure
38、as follows:Degree of cure, % 5 A/B! 3 100 (1)where:A = percent loss in weight, andB = percent volatile matter (7.2).8.2 Procedures B and C (Free Film):8.2.1 Do not remove the specimens from the backing block.Allow the specimens to cure for 7 days at 60 to 80F (15 to27C). At the end of the 7-day peri
39、od transfer the specimens(still on the backing blocks) to a thermostatically controlledoven having a temperature of 150 6 5F (63 to 68C). Hold inthis oven for a minimum of 14 days, and for as long thereafteras may be necessary to reach the desired degree of cure.Determine the degree of cure in accor
40、dance with 8.1.2.8.2.2 Conditioning of Free FilmAllow the specimens tocool, remove them from the backing block, and immerse in tapwater at approximately 50F (10C). When the paper coatinghas softened (usually 20 to 30 min), strip all the paper from thespecimens and rinse them in cool (50F, 10C) water
41、 until nowater-soluble gum remains on the surfaces. Blot carefully toremove excess water and allow to dry at room temperature withgood ventilation. Before using the specimens in further tests,remove and discard the outer 0.050 in. (13 mm) of masticaround the perimeter.8.2.3 Measure dry thickness at
42、several locations to thenearest 0.001 in. (0.025 mm) with a suitable ratchet microme-ter, and record. The dry thickness at any point shall deviate notmore than 10 % from the average thickness.9. Report9.1 Since this practice covers only the preparation andcuring of specimens to be tested by other me
43、thods, no report isnecessary. Data here obtained should be included in the reportof the succeeding test. These data include procedure used, drythickness of specimen, number of coats, presence of primer ormembrane, or both, degree of cure, and any deviation from thestated procedure.10. Keywords10.1 m
44、astic; thermal insulation; thermal insulation coatingASTM 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 ri
45、ghts, 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 fo
46、r 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 hearin
47、g 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 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).C419083
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