ASTM_C_712_-_14.pdf

Designation:C71214Standard Test Method forBubbling of One-Part,Elastomeric,Solvent-Release TypeSealants1This standard is issued under the fixed designation C712;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 This test method covers determination of the degree ofbubble formation or surface blistering in one-part,elastomericsolvent-release type sealants when exposed to elevated tem-peratures.1.2 The subcommittee with jurisdiction is not aware of anysimilar ISO standard.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:2C717 Terminology of Building Seals and SealantsC719 Test Method for Adhesion and Cohesion of Elasto-meric Joint Sealants Under Cyclic Movement(HockmanCycle)3.Terminology3.1 DefinitionsRefer to Terminology C717 for definitionsof the following terms used in this test method:compound,elastomer,elastomeric,sealant,solvent-release sealant,substrate,and standard conditions.4.Significance and Use4.1 The type and amount of solvent used in these sealantscan sometimes give rise to surface bubbling and blisteringproblems.The substrate used,whether porous or nonporous,will also have an effect.Although blistering is often caused bymisapplication,this test method is useful in differentiatingbetween a sealant that develops an acceptably smooth surfaceand one that may have blistering tendencies.5.Apparatus5.1 Plates,thin aluminum,approximately 3 in.(76 mm)wide by 5 in.(127 mm)long by 0.012 in.(0.30 mm)thick.5.2 Blocks,prepare cement mortar,as described in Termi-nology C719 to the following size:approximately 2 in.(51mm)wide by 4 in.(102 mm)long by 1 in.(25 mm)thick.NOTE1Other substrates such as brick,cast stone,marble,stainlesssteel,etc.,may be specified either in place of the standard materialsspecified in 5.1 and 5.2 or in addition to them.5.3 Frame,flat,rectangular,of18-in.(3.2-mm)steel orbrass,with an opening of 1 in.by 334in.(25 mm by 95 mm)and outside dimensions of approximately 2 in.by 434in.(51 mm by 121 mm).5.4 Spatula,steel,with knife edge.5.5 Oven,forced-draft type,having a temperature controlledat 122 6 3.6F(50 6 2C).6.Test Specimen6.1 Take the test specimen from a previously unopenedcontainer as received from the sealant manufacturer.7.Procedure7.1 Prepare three test specimens on each substrate as fol-lows:Center the frame on the test substrate and carefully fill itwith compound,avoiding air pockets.Strike off the surface ofthe compound flush with the frame,to a uniform thickness of18in.(3.2 mm).With the spatula,cut all around the outsideedge of the compound and lift the frame straight up and off.7.2 Condition the specimens for 48 h at standard conditions.7.3 Place the specimens in the oven at 122 6 3.6F(50 62C)for 72 h.7.4 After heat exposure,allow the specimens to cool at 73.46 3.6F(23 6 2C)for 1 h.7.5 Examine each specimen for surface gas bubbles andblisters.1This test method is under the jurisdiction ofASTM Committee C24 on BuildingSeals and Sealants and is the direct responsibility of Subcommittee C24.20 onGeneral Test Methods.Current edition approved Dec.1,2014.Published December 2014.Originallyapproved in 1972.Last previous edition approved in 2009 as C712 03(2009).DOI:10.1520/C0712-14.2For 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 ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 8.Report8.1 For each substrate,report the total surface area coveredby the bubbles or blisters,estimated to the nearest 0.1 in.2(65mm2).The area of bubble formation may be estimated bysuperimposing on the specimen a glass or clear plate ruled into12-in.(13-mm)squares.9.Precision and Bias39.1 The precision and bias calculations for this test methodare based on the results of four laboratories testing threematerials using five specimens per test.The results are given inTable 1.9.1.1 At 95%confidence level a variation of as much as0.59 in.2can be expected within a laboratory and 0.60 in.2between laboratories.This is based on three materials beingtested by four laboratories.10.Keywords10.1 bubbling;elastomeric;solvent-release sealantASTM 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