1、ASTM DLb43 bO m 0757530 0022575 2 m fJ-04-90 4CTb Designation:D 1643-60(Reapproved 1988)Standard Test Methods for Gas Checking and Draft Test of Varnish Films This standard is issued under the fixed designation D 1643;the number immediately following the designation indicates the year of original ad
2、option or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A superscript epsilon(0 indicates an editorial change since the last revision or reapproval.This standard has been approved for irse by agencies o f the Department of Defense to
3、replace Methods 4161,4162,4171 ofFederai Test Method Standard No.141.Consirlt the DoD Index of Specijicaiions and Standards for the specific year o f issue which has been adopted by ihe Department o f Defense.1.Scope 1.1 These test methods cover the determination of the gas checking and draft test o
4、f varnish films.1.2 This standard may involve hazardous materials,oper-ations,and equipment.This standard does not purport to address all o f the safety problems associated with its use.It is the responsibility o f the user o f this standard to establish appropriate safety and health practices and d
5、etermine the applicability o f regulatory limitations prior to use.2.Referenced Document 2.1 ASTM Standard:D 1640 Test Methods for Drying,Curing,or Film Forma-tion of Organic Coatings at Room Temperatme GAS CHECKING 3.Scope 3.l This test method3 covers two alternative procedures for detecting nonuni
6、form appearance that may develop while a film of varnish dries in an atmosphere that has been fouled by products of combustion.The nonuniform appear-ance is generally related to wrinkling,which is sometimes microscopic and which is variously described as checking,crows-footing,crystallization,or dul
7、ling.Appearance non-uniformities that develop on dried films and are described by such terms as orange-peel,haze,silking,flooding,etc.,are not within the scope of this test method.4.Summary of Test Method 4.1 The varnish film under test is exposed to foul gas for various periods before the film has
8、been converted from liquid to substantially solid,since the foul gas is effective,within the scope of these test methods,only,before the varnish film has become set-to-touch or dust-free.PROCEDURE A-BELL JAR TEST 5.Apparatus 5.1 The form and arrangement of the apparatus shail be These test methods a
9、re under the jurisdiction of ASTM Committee D 1 on Paint and Related Coatings and Materials and the direct Responsibility of Subcommittee D 01.33 on Varnish and Resins,Including Shellac.Current edition approved Sept.19,1960.Published November 1960.Originally published as D 1643-59 T.Last previous ed
10、itions D 1643-59 T.Replaces Sections 2 to 1 4 of Method D 154.Antiiral Book ofASTIM Standards,Vol 06.01.See Paint Testing ibanital,ASThf STP 500,ASTM,1972.designed to provide an even distribution of the products of combustion over the test panels.5.1.1 Glass Bell Jar,approximately 8 in.(203 mm)in di
11、ameter and 12 in.(300 mm)in height,inside dimensions,having a ground-glass rim.5.1.2 Ground-Glass Base Plate,of suitable size.5.1.3 Metal Frame,fitted inside the bell jar and provided with a suitable support for holding a tin-plate disk 6 in.(1 52 mm)in diameter in a horizontal position 2 in.(51 mm)
12、above the wick of the lamp.5.1.4 Additional Horizontal Supports,for holding the various varnished panels under test.5.1.5 Small Kerosine Glow Lamp,without a chimney,or a small alcohol lamp fded with kerosine,using a round wick not over 12 in.(6.4 mm)in diameter and adjusted to give a flame of 4/5 in
13、.(20 mm)in height.5.1.6 Tin-plate Panels,3 by 5 in.(76 by 127 mm)or smailer,cut from commercial No.3 1 gage(0.227 mm)bright.tin plate,weighing 0.39 to 0.5 1 lb/ftz(1.9 to 2.5 kg/m2)and carefully cleaned with toluene and dried before use.6.Procedure 6.1 Determine the normal set-to-touch or dust-free
14、drying time of the varnish under test in accordance with Test Methods D 1640.Divide this time by five to arrive at the different drying periods at which the material is to be tested.Thus,if a material sets to touch in 1 h,test the specimens for resistance to gas at drying periods of 12,24,36,and 48
15、min,respectively.6.2 Flow the varnish to be tested on the tin-plate panels at the determined intervals of time.Allow the panels to d&n in a nearly vertical position at room temperature 65 to 75F(18 6.3 After the required interval of drying time has passed,place the panels in a horizontal position on
16、 the upper supports of the frame.Light the lamp and place it on or near the center of the ground-glass base plate.After the bell jar has been placed tightly over the frame and lamp,the flame should extinguish in about 4 min.6.4 Remove the panels and examine for gas effects after they have remained in the jar for 30 min.7.Report to 24C),-BA 7.1 Describe the presence or absence of gas effects on the test panel for each dqing interval.NOTICE:This standard has either been superseded and replaced by
