ASTM_D_3932_-_80_scan.pdf

ASTM D3932 80 07595110 O032932 O I4-52 1 0 Designation:D 3932-80 4CTb AMERICAN SOCIETY FOR TESTING AND MATERIALS 1916 Race St.,Philadelphia,Pa.19103 Reprinted from the Annual Book of ASTM Standards,Copyright ASTM If not listed In the current combined index,will appear in the next edition.Standard Practice for the CONTROL OF THE APPLICATION OF STRUCTURAL FASTENERS WHEN ATTACHED BY HOT MELT ADHESIVE This standard is issued under the fixed designation D 3932;the number immediately following the designation indicates the year of original adoption or,in the case of revision,the year of last revision.A number i n parentheses indicates the year of last reapproval.1.scope 1.1 This method covers the controls neces-sary for the use of hot melt adhesive when used to attach structural fasteners,structural fas-teners being classified as any attachment in-tended to carry a load.This method confines itself to the technique for proper use of the adhesive and does not recommend either the type fastener or the hot melt adhesive to be employed.The areas to be defined are surface preparation in its various forms,and methods for the application of the“hot melts.”Several types of tooling required for the application are described.2.Applicable Documents 2.1 ASTM Standards:D 897 Test for Tensile Properties of Adhesive D 907 Definitions of Terms Relating to Ad-Bonds2 hesives2 3.Description of Terms 3.1 clean surfQce-a surface that is free of foreign material both visible and invisible.A clean surface can be determined by the stand-ard water break test.3.2 water break test-any surface that is chemically clean can be tested by the use of a drop of water,distilled water preferred.If the surface is clean,the water will break and spread;a contaminated surface will cause the water to bead.A clean surface is essential for maximum bond strength.3.3 For Definitions of other terms,refer to Defmitions D 907.4.Apparatus for Surface Preparation and Hot Melt Adhesive Application 4.1 The apparatus required falls into two categories,cleaning materials and application tools.4.1.1 Cleaning Materials 4.1.1.1 Chemical Scrub:(a)Lintless tack rag,(b)Corrosion resistant,steel wool,(c)Chemical solvent compatible with sur-face under preparation,(d)Abrasive power cleaner,and(e)Distilled water.4.1.1.2 Abrasive Cleaning-Abrasive clean-ing can be accomplished in two ways:(a)Sanding with sandpaper of different grades,using a hand or a power sander,and(b)Sandblasting can be used if the area is adaptable.Use clean sand or grit.All residue is to be removed.4.1.1.3 Machining(Material Removal)-Machining requires suitable equipment that can be employed on the area to be cleaned.The exact amount of material to be removed is to be minimal as defined by engineering draw-ing or manufacturing outline.4.1.2 Application Tools-Hot melt adhesive can be applied in two ways:4.1.2.1 A hot melt applicator supplies the adhesive(in a liquid form)on demand to a This practice is under the jurisdiction of ASTM Com-mittee D-14 on Adhesives and is the direct responsibility of Subcommittee 14.80 on Metal Bonding Adhesives.Current edition approved Aug.1,1980.Published October 192.Annual Book of ASTM Standards,Part 22.1 NOTICE:This standard has either been superseded and replaced by a new version or discontinued.Contact ASTM International(www.astm.org)for the latest information.ASTM D3932 80 W 075951iO O032933 2 W designated area.4.1.2,2 The adhesive can be shaped into a gasket form that is positioned between the in-terfaces of the substrate and the fastener and then heated in position to a liquid state and allowed to cool to form a bond.4.2 Heating Tools-The heating tools used to apply the gasket form of the hot melt adhe-sive are tools that can control and direct the heat to a designated area,These fall into three basic types,as follows:4.2.1 Contact(Conductance Tools)-Several forms of this type are available;the simplest is an electrical soldering gun.A type that controls the tip at a constant temperature and provide a timing device is preferred,4.2.2 induciion Heating-This type is the non-contact form that heats the fastener through the use of a positioned coil and micro-waves,The time cycle is very fast and must be controlled on the basis of fastener mass that established the power output and dwell time.4.2,3 Infrared Gun-This is radiant type heating as produced by focused type quartz iodide lamp,The infrared rays produced raise the fastener temperature to a predetermined level.This type requires an automatic timing,4.3 Chill Blocks-A suitable form of con-ducting metal must be used,the size and shape of the block to conform to the fastener being bonded,The block must provide a maximum conductive mass to provide the best heat sink,Several blocks must be available to provide a“leap frog”application for a production cycle.D 3932 5.Precautions 5.1 The control of the application tempera-ture and the dwell time of application is of major importance,Overheating can damage the adhesive and th