Post on 26-Jan-2021
AdhesiveBonding
Text
book
Version:�1.5
©�1999-2014�Inter-Industry�Conference�On�Auto�Collision�Repair
AHD01-STMAN1-E
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Adhesive�BondingTextbook
Table�of�Contents 3
Contents
Introduction..............................................................................................................................7Obligations�To�The�Customer�And�Liability.......................................................................... 7
Module�1�-�Adhesive�Bonding�Materials................................................................................ 13Using�Adhesives................................................................................................................. 13Adhesive�And�Gun�Types................................................................................................... 16Module�Wrap�Up............................................................................................................... 25
Module�2�-�Attachment�Processes.......................................................................................... 29Adhesive�Bonding...............................................................................................................29Weld�Bonding.....................................................................................................................31Rivet�Bonding�Steel�Vehicles.............................................................................................. 33Rivet�Bonding�Aluminum�Vehicles..................................................................................... 35Module�Wrap�Up............................................................................................................... 37
Module�3�-�Two-Part�Adhesive�Bonding�Repairs.....................................................................41Part�Removal�And�Cleaning................................................................................................ 41Preparation�For�Part�Attachment......................................................................................... 43Attachment�Considerations................................................................................................. 45Module�Wrap�Up............................................................................................................... 46
Module�4�-�One-Part�Adhesive�Bonding�Repairs.................................................................... 49Part�Removal�And�Cleaning................................................................................................ 49Preparation�For�Part�Attachment......................................................................................... 51Attachment�Considerations................................................................................................. 51Module�Wrap�Up............................................................................................................... 52
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Introduction
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IntroductionTextbook
Adhesive�Bonding 7
Obligations�To�The�Customer�And�Liability
The�collision�repair�industry�has�anobligation�to�correctly�repair�thecustomer’s�vehicle.�Collision�repairs�mustbe�performed�using:
• recommended�or�testedprocedures�from�vehicle�makers,I-CAR,�and�other�research�andtesting�organizations.
• quality�replacement�parts�andmaterials.
• repair�processes�and�parts�aswritten�and�agreed�upon�in�therepair�order.�If�items�on�the�repairagreement�are�not�consistentwith�the�repair�order,�it�can�beconsidered�fraud.
Performing�proper�collision�repairsrequires�using�parts�and�procedures�thatkeep�remaining�warranties�intact.
Collision�repairs�must�restore:
• safety.• structural�integrity.• durability.• performance.
• fit.• finish.
Throughout�the�damage�analysis�andrepair�process�the�repairer�and�insurermust:
• communicate�with�each�other.• maintain�constant�communication
with�the�customer.• be�in�agreement�with�each�other
and�the�customer�on�how�repairswill�be�performed.
• inform�the�customer�of�anychanges�in�the�repair�plan�fromthe�original�repair�agreement,�andexplain�the�changes�and�why�theyhave�to�be�made.
To�reduce�liability:
• make�sure�that�all�repairs�areperformed�thoroughly,�correctlyand�as�listed�in�the�damage�report.
• follow�proper�procedures.• have�documentation�of�required
repairs�with�detailed�recordkeeping�available�for�customers.
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Adhesive�Bonding 8
Technicians�are�considered�theexperts�and�are�expected�to�beknowledgeable�on�how�to�performa�quality�repair.
Liability�insurance�that�covers�the�repairfacility�may�not�always�cover�all�damages.For�example:
• the�policy�may�not�coverfaulty�repairs,�leaving�liabilityresponsibility�completely�on�thefacility.
• a�shop�owner�may�find�that�repairfacility�liability�coverage�may�notcover�the�full�amount�awarded�ina�lawsuit.�The�shop�owner�wouldhave�to�pay�the�difference.
It�is�difficult�to�reduce�the�risk�of�liabilityexposure.�The�part�that�the�repairer�cancontrol�is�the�chance�of�being�found�atfault.�Chances�can�be�minimized�by:
• using�recommended�or�testedprocedures�from�the�vehiclemakers,�I�CAR,�or�other�researchand�testing�organizations.
• using�quality�replacement�partsand�materials�that�restore�fit,
finish,�durability,�and�perform�atleast�as�well�as�the�original.
• keeping�thorough�records.
Keeping�thorough�records�includes�morethan�recording�the�date,�mileage,�and�pre-existing�damage.�Record�keeping�alsoincludes:
• making�sure�all�notes�are�legible.• verifying�the�repairs�that�were
made�or�not�made.• having�the�customer�sign�a
waiver�for�repairs�that�they�donot�want�performed.�Repairersmust�determine�their�liability�onnot�repairing�safety�systems�suchas�restraint�and�anti-lock�brakesystems.
• keeping�computer�printouts�orworksheets�on�file�showing�wheelalignment�readings�or�vehicledimensions�before�and�afterrepairs.
• keeping�scan�tool�printouts�andrecords�of�computer�codes�forairbag,�anti-lock�brake,�emission,and�powertrain�control�module(PCM)�systems.
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Adhesive�Bonding 9
• attaching�the�OEM�or�other�testedprocedure�printout�to�the�vehiclerepair�order.
• keeping�receipts�for�all�subletwork�performed.
Refer�to�"Video:�Topics�Off�Limits"�in�thepresentation.�This�video�identifies�topicsthat�should�not�be�brought�up�in�class.
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Module�1�-�AdhesiveBonding�Materials
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Module�1�-�Adhesive�Bonding�MaterialsTextbook
Adhesive�Bonding 13
Using�Adhesives
The�learning�objectives�for�this�moduleincluded:
• identifying�some�vehicle�makersthat�use�adhesives.
• describing�the�difference�betweenepoxy,�acrylic,�and�urethanematerials.
• describing�the�difference�betweenadhesive�and�cohesive�failure.
• describing�the�considerations�forworking�with�adhesives.
Refer�to�“Video:�General�Safety”�in�thepresentation.�This�video�presents�thegeneral�safety�requirements�for�the�livedemonstrations�participation.
Adhesive�should�be�applied�as�recommended�bythe�adhesive�maker�and�only�to�vehicles�that�haveendorsements�from�the�vehicle�maker.
Some�companies�that�use�adhesives�for�atleast�one�repair�process�include�vehiclemakers�such�as:
• Audi�on�the�A8,�which�uses�rivetbonding.
• BMW�on�the�5�and�6�Series,�thatuse�an�adhesive-only�insert�in�thesection�joint�of�the�lower�front�rail.
• the�Chrysler�Group,�whichuses�extensive�weld�bondingparticularly�around�the�passengercompartment.
• Ford�on�the�F-150,�which�usesweld�bonding�on�the�uniside.
• General�Motors,�which�usesadhesives�for�attaching�door�skins.
• Jaguar�on�the�XK,�which�usesextensive�rivet�bonding�throughoutthe�vehicle.
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Adhesive�Bonding 14
This�flange�uses�adhesive�and�self-piercing�rivets(SPRs).
If�exterior�body�panels�are�being�attachedusing�adhesive�bonding:
• follow�the�vehicle�maker’sprocedures�when�using�a�vehiclemaker’s�private�label�adhesive.When�using�an�adhesive�that�isnot�private�labeled�by�the�vehiclemaker,�but�is�from�the�adhesivemaker,�follow�the�adhesive�maker’sprocedure�for�doing�a�repair.
• verify�that�the�vehicle�makerallows�an�adhesive-only�repair.An�adhesive-only�repair�doesnot�use�welds,�rivets,�or�othermechanical�fasteners.�Anchorwelds�may�be�required�in�certainareas�for�adhesive-only�repairs.These�typically�include�roof�skinsand�quarter�panels.�Anchor�weldsare�welds�that�are�typically�locatedat�the�corners�of�a�part�and�helpkeep�a�part�from�being�peeled�offthe�vehicle.
• some�vehicle�makers�requireusing�welds�and�adhesive.�Usingadhesives�and�welds�is�calledweld�bonding.�Depending�onwho�supplies�the�reattachmentprocedure,�the�part�may�be
attached�using�bonding�andeither�GMA�(MIG)�plug�weld�orspot�welds.�The�Chrysler�Groupuses�spot�weld�bonding�on�theirvehicles.�Ford�requires�plug�weldbonding�where�spot�welder�armswill�not�reach.�One�of�theseprocesses�is�when�reattachinga�uniside�on�a�2004�and�newerF-150.�More�information�on�weldbonding�can�be�found�in�the�I-CARlive�“Squeeze-Type�ResistanceSpot�Welding�(WCS04)”�trainingcourse.
• some�vehicle�makers�requireusing�rivets�and�adhesive.�Usingadhesives�and�rivets�is�calledrivet�bonding.�Many�aluminum-intensive�vehicles�use�rivetbonding�on�both�structural�andnon-structural�locations�on�thevehicle.�Land�Rover�uses�rivetbonding�for�reattaching�some�doorskins.�More�information�on�rivetbonding�can�be�found�in�the�I-CARlive�Aluminum-Intensive�VehicleRepairs�(ALI01)�training�course.
In�Module�2,�adhesive-only,�weld,�andrivet�bonding�will�be�discussed�further.
Safety�data�sheets�may�offer�safety�information.
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Adhesive�Bonding 15
Personal�SafetyRefer�to�the�saftey�data�sheet�(SDS)�toensure�that�proper�personal�protectiveequipment�is�being�used,�and�safehandling�during�clean�up�and�disposal�arebeing�followed.
When�working�with�adhesives:
• follow�the�instructions�provided�bythe�vehicle�maker�if�the�productbeing�used�is�labeled�from�thevehicle�maker.�The�vehicle�makermay�recommend�following�theproduct�maker’s�instructionsfor�part�preparation�and�someapplication�considerations.�Inthis�situation,�make�a�note�in�thecustomer’s�file�that�two�separateprocesses�were�used.
• follow�the�adhesive�maker’srecommendations�if�the�productbeing�used�is�not�OEM-labeled.For�example,�if�the�vehicle�makerrecommends�the�use�of�a�productbrand,�follow�those�productinstructions.
• record�the�name,�part,�and�lotnumber�of�the�materials�usedfor�the�repair.�This�can�be�doneby�writing�the�information�onthe�repair�order,�or�removingthe�label�from�the�used�cartridgeand�attaching�it�to�a�sheet�ofpaper,�and�placing�it�in�thecustomer’s�file.�Retaining�this�typeof�information�may�prove�helpfulif�there�is�a�product�recall�or�legalaction�regarding�the�repair.
International�Epoxies�&�Sealers
PLIOGRIP�Valvoline
Norton�Automotive
http://www.internationalepoxies.com/http://www.pliogripbyvalvoline.com/http://www.nortonautomotive.com/adhesives-sealers.aspx
Module�1�-�Adhesive�Bonding�MaterialsTextbook
Adhesive�Bonding 16
LORD
3M�Collision
SEM�Products
Refer�to�Module�1,�“Demonstration:Adhesive�Maker�Information”�in�thepresentation�for�information�on�adhesivemaker�information.
Adhesive�And�Gun�Types
This�shows�a�urethane�based�product.
This�shows�an�acrylic�based�product.�Some�adhesivemakers�may�refer�to�their�acrylic�based�products�asmethacrylate.
This�shows�an�epoxy�based�adhesive.
http://www.lord.com/http://3mcollision.com/products/adhesiveshttp://www.semproducts.com/
Module�1�-�Adhesive�Bonding�MaterialsTextbook
Adhesive�Bonding 17
This�shows�a�combination,�or�hybrid,�product�usingurethane�and�epoxy�bases.
There�are�three�main�types�of�adhesivesused�in�the�automotive�industry.�Theseinclude:
• acrylic-based�adhesives.�Acrylicsare�typically�two-part�materialsthat�cure�by�chemical�reaction.Acrylics�cure�faster�than�urethanesand�epoxy-based�materials.
• epoxy-based�adhesives.�Epoxiesare�two-part�materials�that�cure�bya�chemical�reaction�and�can�havetheir�cure�rate�accelerated�withheat.
• urethane-based�adhesives.Urethanes�are�typically�one-partmaterials.�One-part�urethanes�curewith�the�presence�of�moisture.Two-part�urethanes�chemicallycure�and�can�be�accelerated�withheat.
Some�adhesive�makers�have�products�thatcombine�bases�like�urethane�and�epoxy�tomeet�specific�applications.
Depending�on�the�adhesive�maker,material�may�be�available�in�volumes
of�6.0�oz�to�13�oz.�One-part�adhesivesare�packaged�as�a�single�tube.�Two-partadhesives�are�packaged�as�two�tubes�thatare�dispensed�together�through�a�singlemixing�tip.
Mixing�tips�are�product�and�materialspecific�and�should�not�be�switchedbetween�brands�or�material�types,because�all�materials�are�chemicallyunique�and�may�be�mixed�at�differentrates.�If�not�properly�mixed,�an�inadequaterepair�may�occur�from�an�incorrect�cureor�mixing�rate.
Some�mixing�tips�use�different�lengthaugers.�As�an�example,�some�companiesuse�mixing�tips�for�expandable�two-part�foams�that�will�fit�on�their�two-part�adhesive�materials,�and�the�onlydifference�between�the�mixing�tips�is�thelength�of�the�auger.�In�situations�like�this,mark�the�mixing�tips�to�indicate�whichproduct�it�should�be�used�with.
Specific�preparation�steps�can�be�found�in�thetechnical�data�sheet.
Characteristics�of�adhesives�include:
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• the�ability�to�cure�relativelyquickly�at�room�temperature.Force�curing�is�not�allowed�for�alladhesives.
• strength,�depending�on�theadhesive�used.
• preparing�the�substrate�differentlythan�is�typically�done�for�welding,riveting,�or�bolting�parts�together.
• impact�resistance.
More�information�regarding�partpreparation�will�be�discussed�in�Module3.
Adhesive�failure�is�typically�a�result�of�improperpreparation�(left).�Cohesive�failure�is�not�typicallyassociated�with�preparation�(right).
Adhesive�failure�is�when�the�adhesivedoes�not�hold�to�substrates�such�as�baremetal,�primer,�or�topcoats.
To�help�prevent�adhesive�failure,�alwayswork�with�clean�surfaces�that�areprepared�following�the�adhesive�maker’sinstructions.�If�a�substrate�is�not�abradedproperly,�or�if�the�bonding�surface�is�notfree�of�contaminants,�adhesive�failure�canresult.
Cohesive�failure�is�when�the�adhesive�failsto�remain�intact�with�itself.�An�example�of
cohesive�failure�would�be�two�parts�beingseparated�and�the�adhesive�remainingattached�to�both�substrates.
To�help�prevent�cohesive�failure,�adhesiveshould�not�be�used�if�it�has�expired,�if�therecommended�work�time�is�exceeded,or�if�the�cure�time�has�been�acceleratedtoo�aggressively.�Not�using�the�adhesivein�a�manner�instructed�by�the�adhesivemaker�can�cause�the�adhesive�to�failprematurely.
Refer�to�Module�1,�“Demonstration:Cohesion�And�Adhesion�Failure”�in�thepresentation�for�a�videoand�example�ofcohesion�and�adhesion�failure.
When�preparing�an�adhesive�cartridge,�there�arespecific�steps�that�should�be�followed�to�help�ensurequality�results.
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Personal�SafetyWhen�working�with�adhesives,�chemical-resistant�gloves�should�be�worn�becausethe�adhesive�may�cause�skin�irritation.Depending�on�the�person�and�theexposure,�eye�irritation�may�also�occurfrom�working�with�adhesives.
To�prepare�two-part�adhesive�cartridges:
1. Dispense�a�small�amount�ofadhesive�before�attaching�themixing�tip.�This�levels�the�plungersand�ensures�the�material�is�flowingfrom�both�sides�of�the�cartridgeequally.
2. Attach�the�mixing�tip.3. Dispense�a�test�bead�the�length
of�the�mixing�tip.�This�ensures�theadhesive�is�thoroughly�mixed.
Refer�to�“Video:�Preparing�The�Cartridge”in�the�presentation.�This�video�showspreparing�a�cartridge�for�dispensingadhesive.
Whenever�possible,�work�within�the�temperaturewindow�recommended�by�the�adhesive�maker.
Temperature�is�important�when�applyingadhesives.�To�ensure�proper�cure�time,the�temperature�of�the�mating�surfaces,adhesive,�and�repair�facility�should�bebetween�65�-�85°F.
For�situations�where�these�conditions�arenot�possible,�consult�the�adhesive�makerfor�instructions.
If�the�temperature�is�too:
• warm,�the�wet,�clamp,�and�curetime�of�the�adhesive�will�decrease.
• cool,�the�wet,�clamp,�and�curetime�of�the�adhesive�will�increase.Wet�time�is�the�time�from�whenthe�adhesive�has�been�dispenseduntil�the�parts�must�be�attached.Clamp�time�is�how�long�parts�mustremain�under�pressure.�Cure�timeis�the�time�required�before�a�partcan�be�placed�into�service.
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When�working�with�adhesives,�wet�or�work�time�isthe�first�window�of�time�that�must�be�followed.
Wet�or�work�time�is�how�long�from�whenthe�adhesive�is�applied�to�when�the�partsmust�be�attached�and�clamped�in�place.
It�is�important�to�monitor�wet�timebecause�a�weak�bond�may�result�ifthe�panel�is�installed,�repositioned,�orclamped�to�the�substrate�after�the�wet�timehas�expired.
For�most�adhesives,�wet�time�is:
• specified�at�50%�relative�humidityand�70°F.
• halved�for�every�20°F�increase.• doubled�for�every�20°F�decrease.
Some�adhesive�makers�say�that�thewet�time�is�starting�to�expire�when�theadhesive�changes�color�as�it�cures.
If�the�bond�is�not�made�before�the�wettime�expires,�the�adhesive�must�beremoved�and�re-applied.�This�is�becausethe�adhesive�may�begin�to�dry�and�notadequately�“bite”�into,�or�adhere�to�thesubstrate.
Clamp�or�handling�time�follows�wet�time.
Clamp�or�handling�time�is:
• not�part�of�wet�time.• the�required�time�that�parts�must
remain�joined�with�pressureapplied.
• commonly�less�than�cure�time.• not�intended�for�the�part�to�be
placed�in�service,�but�allows�forsome�limited�transportation.�Thisalso�includes�installing�a�part�ona�vehicle�and�then�raising�thatvehicle�on�a�hoist�before�the�curetime�has�been�reached.
There�may�be�situations�when�an�adhesivemaker�lists�an�unclamp�time.�Unclamptime�is�when�the�clamps�can�be�removedfrom�the�part,�but�the�part�should�notbe�placed�into�service.�Unclamp�time�isbefore�the�cure�time�has�been�reached.
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Cure�time�is�the�last�time�frame�to�be�followed�whenworking�with�adhesives.
Cure�time�is�the�specific�time�requiredfor�an�adhesive�to�dry�or�set�at�a�specifictemperature�and�humidity.�When�anadhesive�cures,�the�material�changes�state.Only�after�the�material�cures�should�thepart�be�placed�in�service.
Most�adhesives�are�designed�to�cureat�70°F.�Two-part�adhesives�cure�by�achemical�reaction�from�mixing�the�twomaterials,�a�resin�and�a�hardener�orcatalyst.
Some�adhesive�makers�allow�forcecuring�two-part�adhesives�to�decreasethe�cure�time.�Force�curing�with�heat�isnot�allowed�on�most�two-part�acrylicadhesives�because�heat�breaks�down�thechemical�structure�of�the�adhesive.
When�allowed,�force�curing�can�bedone�using�heat�from�an�infrared�heatlamp,�heat�gun,�temperature-controlledspraybooth,�etc.�When�using�heat�toshorten�cure�time,�follow�the�productmaker’s�instructions.
Do�not�heat�bonded�parts�with�an�openflame.
Corrosion�protection�requirements�will�be�identifiedby�each�adhesive�maker.
Adhesives�that�do�not�require�a�primer�tothe�bond�area:
• are�commonly�available�forbonding�metal�parts.
• are�designed�to�be�applied�to�bare-metal�areas,�and�protect�againstcorrosion.
• must�cover�all�of�the�bare�metalto�provide�protection.�Failureto�cover�all�bare�metal�surfaceswill�result�in�corrosion�that�couldcreep�under�the�adhesive�andcause�an�adhesive�failure.
When�working�with�an�adhesive�thatrequires�a�primer,�clean�the�matingsurfaces�and�apply�a�primer�beforeapplying�the�adhesive.
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Brushes�can�be�used�to�help�spread�the�adhesive�tocover�bare�metal�areas.
For�bare-metal�mating�surfaces,�applyadhesives�with�corrosion-resistantproperties�as�follows:
1. Apply�a�1/4"�-�3/8"�bead�ofadhesive�to�the�bond�areas�of�allparts.
2. Smooth�the�adhesive�bead�alongthe�entire�area�to�be�bondedusing�a�plastic�spreader.�Makesure�all�bare�metal�bonding�areasare�covered�to�ensure�propercorrosion�protection.
3. If�necessary,�apply�an�additionaladhesive�bead�to�the�inside�edgeof�the�replacement�panel,�or�tothe�flange�on�the�vehicle�structure.The�additional�bead�of�adhesiveis�to�ensure�adequate�bond-line�thickness,�and�reduce�thepossibilities�of�air�bubbles�in�theadhesive�bead.
4. Install�the�part.
One-part�adhesives�typically�do�not�containcorrosion-resistant�properties.
When�working�with�an�adhesive�thatrequires�primed�mating�surfaces:
1. Begin�with�coated�flanges�asrecommended�by�the�adhesivemaker.
2. Apply�a�1/4"�-�3/8"�bead�ofadhesive�to�either�the�replacementpanel�flange�or�the�vehicle�flange.
3. Do�not�smooth�the�adhesive�bead.Allow�the�adhesive�to�cover�thejoint�from�the�pressure�applied�atthe�repair�joint.
4. Assemble�and�clamp�the�partstogether.�When�applying�clampingpressure,�glass�beads�insidethe�adhesive�help�control�over-clamping.
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Apply�adhesive�completely�around�the�holes�that�arein�parts�to�be�bonded.
When�applying�adhesive�to�a�part,�theadhesive�should�be:
• a�continuous�non-breaking�beadthat�is�overlapping�at�the�start�andstop�locations�of�the�bead.
• of�uniform�size�around�the�panelon�the�bonding�area.
• applied�around�holes�on�a�part�toprovide�proper�bonding�strength.
Inadequate�bond-line�thickness�can�occur�from�notapplying�a�large�enough�adhesive�bead.
Bond-line�thickness:
• is�the�thickness�of�the�curedadhesive�in�the�joint.
• may�affect�the�rate�that�theadhesive�cures.�If�the�bond�lineis�too�large,�areas�of�the�adhesivemay�cure�quicker�than�othersbecause�of�the�heat�generated�bythe�adhesive.
• may�be�controlled�by�the�size�ofglass�beads�used�in�the�adhesive.To�ensure�proper�bondlinethickness,�some�adhesives�containglass�beads�to�prevent�a�bond�linethat�is�too�thin.�For�adhesives�thatdo�not�contain�glass�beads,�anover-clamped�joint�will�result�ina�bond�line�that�is�too�thin.�Someplastic�adhesives�do�not�containglass�beads,�and�are�so�thick(viscous)�that�controlled�clampingcan�help�create�an�adequate�bondline.
Corrosion-resistant�material�should�be�used�whenmaking�shims.
Adhesives�used�for�plastics,�and�afew�products�used�for�steel,�do�notcontain�glass�beads.�When�working�withthese�types�of�materials,�shims�may�be
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Adhesive�Bonding 24
required�for�creating�a�proper�bond-linethickness.
When�unsure�about�the�adhesive�beingused,�refer�to�the�adhesive�maker’srecommendations�for�maintaininga�consistent�and�specific�bond-linethickness.�Depending�on�how�the�bondline�is�maintained,�use�care�to�not�over-clamp�the�panels.
Storing�open�adhesive�containers�may�be�differentfor�each�adhesive�maker.
Environmental�SafetyWhen�disposing�of�adhesive,�always�referto�the�SDS,�and�follow�local,�state,�andnational�environmental�control�methods.Cured�adhesive�may�be�disposed�of�asnon-hazardous�waste.
Adhesives�are�usually�guaranteed�for�6-�12�months�from�the�date�of�purchase,depending�on�the�adhesive�maker.�Thisis�known�as�the�shelf�life.�To�ensuremaximum�shelf�life,�store:
• adhesives�in�a�clean,�dry�areaat�65�-�85°F,�and�out�of�directsunlight.
• both�one-�and�two-part�adhesivesin�relatively�low�humidity.
• partially�used�adhesives�withthe�mixing�tip�attached�to�thecartridge.�Some�adhesive�makersrecommend�removing�the�mixingtip�and�replacing�it�with�theoriginal�packaging�plug.�Acrylicand�urethane�adhesives�aremoisture�sensitive�and�must�beprotected�from�relatively�highhumidity.�To�protect�adhesivesfrom�humidity,�do�not�open�theproduct�package�until�the�productwill�be�used.�Store�any�partiallyused�cartridges�in�an�airtightplastic�bag.
After�a�product�has�been�opened,�theshelf�life�will�be�reduced.�To�ensurequality,�keep�a�minimum�inventory�ofopened�products.�If�an�adhesive�makerrecommends�that�the�cartridge�be�storedwith�the�nozzle�end�down,�it�may�be�tokeep�air�from�entering�the�cartridges.�Ifan�adhesive�maker�recommends�that�thecartridges�be�stored�upright,�it�may�be�tokeep�any�air�in�the�cartridges�at�the�top�soit�can�be�purged�easily.
If�an�adhesive�shelf�life�has�expired,discard�the�material.�If�a�product�is�beingdiscarded,�non-dispensed�productsare�considered�hazardous�waste.�Todispose�of�the�material�so�it�is�considerednonhazardous�waste,�dispense�theproduct�and�let�it�cure.�When�the�materialchanges�state�to�a�solid,�it�is�typically�notconsidered�a�hazardous�material.
Module�1�-�Adhesive�Bonding�MaterialsTextbook
Adhesive�Bonding 25
Specific�applicators�may�be�required�for�someadhesives.
Two�types�of�applicators�for�dispensingcartridges�of�adhesives�are�manual�andpneumatic.
Manual�applicators�are�usually�a�ratchettype,�similar�to�a�caulking�gun,�andmay�be�designed�for�specific�brands�ofadhesive.
Pneumatic�applicators�are�generally�usedto�help�make�dispensing�the�producteasier.�By�using�a�pneumatic�applicator,the�dispensed�bead�can�be�controlledeasier.
Pneumatic�applicators�often�requirespecific�steps�for�loading�and�use.�Do�notapply�full�working�air�pressure�to�a�newadhesive�cartridge.�Excessive�pressure�cancause�the�cartridge�to�deform�or�crack,causing�poor�adhesive�flow�and�mix.�Toomuch�air�pressure�can�also�cause�adhesiveblow-by�and�leakage�inside�the�cartridgeor�gun.
When�using�a�pneumatic�applicator,slowly�increase�the�air�pressure�until
full�working�pressure�is�reached.�Whenusing�pneumatic�applicators,�follow�theproduct�maker’s�recommendations�whilecontinually�checking�for�a�consistent�mixof�two-part�products.
Depending�on�the�material�beingused,�an�adhesive�maker�may�have�aspecific�applicator�gun�designed�for�theirproduct.
Module�Wrap�Up
The�topics�discussed�in�this�moduleincluded:
• vehicle�makers�who�use�adhesives.• the�three�types�of�adhesives.• the�difference�between�adhesive
and�cohesive�failure.• considerations�for�working�with
adhesives.
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Module�2�-AttachmentProcesses
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Adhesive�Bonding 29
Adhesive�Bonding
Learning�objectives�for�this�moduleinclude:
• describing�different�types�of�weldbonding.
• describing�the�types�of�rivets�usedfor�rivet�bonding.
• explaining�special�considerationsfor�using�adhesives�for�aluminumrepair.
Currently,�vehicle�makers�recommend�using�a�lapjoint�for�bonding.
When�doing�adhesive-only�attachmentprocesses:
• adhesive�is�the�only�material�usedto�hold�the�parts�together.
• lap�joints�are�used.�A�lap�joint�isone�substrate�resting�parallel�andin�contact�with�another�substrate.
• only�the�adhesive�is�used�forholding�the�parts�together.�Anexception�to�this�is�the�hemmedflange�of�a�door�skin�that�alsohelps�to�lock�the�panel�in�place.
Some�door�skins�are�attached�with�adhesive�only.
Considerations�for�doing�adhesive-onlybonding�include:
• corrosion�resistance.• no�heat�being�introduced�into�the
repair�zone.• extended�work�times,�and
the�ability�to�reposition�a�partafter�attachment�and�clampingcompared�to�mechanical�fasteningmethods.
• no�mechanical�fasteners�such�asbolts�or�rivets.
• limited�acceptance�for�use�withstructural�parts.�As�of�2006,the�only�structural�part�that�isadhesively�bonded�on�a�mass-produced�production�vehicle�is�forthe�front�lower�rail�crush�cap�onthe�BMW�5�and�6�Series.
• the�procedure�being�acceptedby�the�vehicle�maker.�Mostvehicle�makers�have�an�acceptedprocedure�on�most�vehicles.�Thisis�for�replacing�door�skins.
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Adhesive�Bonding 30
Refer�to�Module�2,�“Demonstration:Adhesive-Only�Bonded�Coupons”�inthe�presentation�for�a�demonstration�ofadhesive-only�bonded�coupons.
Some�roof�panels,�like�this�carbon�fiber�roof,�arebonded�to�the�vehicle�structure.
Some�parts�that�may�be�attached�usingadhesives�only�include:
• roof�panels.• quarter�panels.• door�skins.• rear�body�panels.• floor�pans�like�that�of�the
Chevrolet�Z06�Corvette.• stationary�glass.• trim.
Replacement�parts�for�the�front�lowerrail�of�the�BMW�5�and�6�Series�are�alsoadhesively�bonded.
Not�all�vehicle�makers�approve�theuse�of�adhesives.�Even�with�those�thatdo,�if�adhesive�is�recommended�for�aspecific�part�those�guidelines�should�notnecessarily�be�applied�to�that�same�parton�a�different�model.
Refer�to�“Video:�Adhesively�BondedSectioning�Joint”�in�the�presentation.�Thisvideo�shows�doing�a�repair�to�a�frontlower�rail�using�adhesives�and�an�insertonly.
Adhesively�Bonded�Sectioning�JointThis�is�an�example�of�what�thereplacement�part�and�the�inserts�used�tosection�a�front�rail�using�an�adhesivelybonded�joint�may�look�like.�This�videowill�focus�on�the�use�of�one�of�theinserts.
A�cut�line�is�measured�and�markedaround�the�replacement�part.�A�largereciprocating�saw�is�used�to�cut�throughthe�rail�at�the�line,�and�the�edge�is�dressedto�provide�a�smooth�sectioning�joint.
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Adhesive�Bonding 31
A�point�half�the�width�of�the�rail�ismeasured�and�marked.�This�marks�wherea�hole�will�be�drilled�to�allow�the�boltto�slide�halfway�into�this�part�and�theoriginal�rail.�The�small�piece�that�wascut�from�the�replacement�rail�is�usedto�simulate�the�original�rail�so�that�acutaway�view�of�the�repair�can�be�seen.The�replacement�rail�is�clamped�onto�theoriginal�rail,�a�pilot�hole�is�drilled�andenlarged�using�a�drill�bit�a�size�largerthan�the�bolt�diameter.�The�insert�is�test-fitted.
The�coatings�are�removed�from�thereplacement�rail�in�preparation�for�theadhesive.�Sanding�dust�is�removed�usinga�vacuum.�Next�the�coatings�are�removedfrom�our�simulated�original�rail.�Thecoatings�are�also�removed�from�theoutside�of�the�insert.
The�adhesive�application�areas�arecleaned.�The�insert�is�flame-treated�andprimer�is�applied.�The�original�rail�and�thereplacement�rail�are�also�flame-treatedand�primer�is�applied.�The�adhesive�isprepared�and�applied�to�the�insert.�Theadhesive�is�spread�out�over�the�surface�ofthe�insert�to�the�recommended�distancefrom�the�bolt.
After�the�adhesive�has�been�sufficientlyapplied,�the�insert�is�installed�into�theoriginal�and�replacement�rail.�The�bolt�istightened�and�the�insert�expands�until�itcreates�a�slight�curve�in�the�surface.�Smallmetal�ridges�in�the�insert�allow�for�theproper�bond-line�thickness.
After�the�adhesive�has�cured,�the�boltis�removed�and�seam�sealer�is�appliedaround�the�sectioning�joint.
Weld�Bonding
Weld�bonding�can�be�done�with�GMAW�(MIG)�orSTRSW�equipment.
The�process�of�weld�bonding:
• uses�welds�and�adhesives.�Thewelds�used�may�be�GMA�(MIG)plug�welds,�or�squeeze-typeresistance�spot�welds�(STRSW).
• is�recommended�by�the�vehiclemaker.�As�of�2006,�the�ChryslerGroup�approves�the�use�of�spotweld�bonding,�and�Ford�approvesboth�spot�welds�or�GMA�(MIG)plug�welds�in�conjunction�withadhesives.
• may�use�welds�for�anchors.Anchor�welds�are�not�consideredweld�bonding.�This�is�because�thewelds�are�used�with�the�adhesiveas�another�separate�attachmentmethod.
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Adhesive�Bonding 32
Adhesive�can�be�seen�between�the�welds�on�this�testweld�bond.
Considerations�for�weld�bondinginclude:
• corrosion�at�the�weld�area�fromheat�and�improper�corrosionprotection,�or�from�the�adhesivebeing�burned�away.
• damaged�coatings�or�weakenedmetal�caused�by�the�heat�fromwelding.
• the�strength�of�a�joint�from�thecombination�of�adhesives�andwelds.
• less�noise,�vibration,�andharshness�(NVH)�by�using�multipleattachment�methods�for�attachingparts.
• contamination�of�the�weld�fromthe�adhesive�contacting�the�GMA(MIG)�weld�puddle.
• fire.�Weld�bonding�throughuncured�adhesive�can�cause�a�fire.
• vehicle�maker�acceptance�forweld�bonding�on�their�vehicles.
Refer�to�Module�2,�"Demonstration:�Weld-Bonded�Coupons"�for�a�demonstration�ofweld-bonded�coupons.
The�Chrysler�Group�and�Ford�Motor�Company�havepublished�weld-bonding�procedures.
Both�the�Chrysler�Group�and�Ford�haveweld�bonding�recommendations.
General�Motors�has�adhesive�bondingprocedures�for�repairs�on�some�models.
Some�vehicle�makers�that�recommend�theuse�of�adhesives�will�have�informationthat�can�be�used�to�determine�whichadhesive�to�use.
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Adhesive�Bonding 33
Refer�to�Module�2,�"Demonstration:Vehicle�Maker�Adhesive�Lists"�for�anexample�of�some�adhesive�listed�by�somevehicle�makers.
Refer�to�“Video:�Weld�BondingReplacement�Parts”�in�the�presentation.This�video�shows�weld�bonding�a�non-structural�replacement�part.
Rivet�Bonding�Steel�Vehicles
Rivets�are�used�on�this�service�part�where�spot�weldswere�used�on�the�cowl�panel.
Though�typically�used�on�aluminum-intensive�vehicles,�rivet�bonding�isslowly�being�applied�to�steel�vehicles.An�example�is�on�the�replacement�ofthe�lower�front�rail�on�General�Motorsvehicles�with�laminated�steel�cowls.
Rivet�bonding�on�steel�vehicles�usesadhesives�and�rivets�for�attaching�partsthat�were�originally�attached�with�spotwelds.
These�steel�rivets�are�used�on�steel�vehicles.
When�doing�repairs�to�steel�vehicles,steel�blind�rivets�are�used�as�reattachmentfasteners�in�most�situations.�This�helpseliminate�galvanic�corrosion�from�the�twodissimilar�metals.
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Adhesive�Bonding 34
Pneumatic�rivet�tools�are�used�to�install�large�steelrivets.
Some�considerations�for�using�rivetbonding�include:
• no�heat-affect�zone.• vehicle�maker�acceptance.• replacement�of�factory�spot�welds.• corrosion�protection�methods.• special�tools�that�may�be�required.
Refer�to�Module�2,�"Demonstration:�Rivet-Bonded�Coupons"�for�a�demonstration�ofrivet-bonded�coupons.
Some�service�parts�are�supplied�with�the�repairprocedure�and�attachment�parts.
Tool�and�part�considerations�for�rivetbonding�on�steel�vehicles�may�include:
• general�rivet�tools�such�as�hand-operated�blind�rivet�tools.
• vehicle�maker�supplied�orrecommended�tools.
In�some�situations,�the�recommendedrivets�are�supplied�with�the�replacementpart.�Supplying�the�rivets�with�the�parthelps�ensure�the�correct�fasteners�areinstalled.
General�Motors�instructs�rivet�bonding�the�lower�railson�vehicles�with�laminated�steel�cowls.
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Adhesive�Bonding 35
General�Motors�recommends�rivetbonding�the�front�lower�rails�on�vehicleswith�laminated�steel�cowls.
Refer�to�“Video:�Rivet�Bonding”�in�thepresentation.�This�video�shows�replacinga�front�lower�rail�using�rivet�bondingprocesses,�along�with�GMA�(MIG)�plugwelds�to�reattach�a�part�that�was�originallyattached�with�spot�welds�by�the�vehiclemaker.
Rivet�Bonding�Aluminum�Vehicles
Rivet�bonding�is�applied�to�the�A-pillar�on�thisaluminum�vehicle.
Rivet�bonding�on�aluminum-intensivevehicle�uses�adhesives�and�rivets�for�theattachment�of�parts�that�were�originallyattached�with�spot�or�laser�welds�orrivets.
Rivet�bonding�is�common�for�bothstructural�and�non-structural�repairs.
Depending�on�the�vehicle�maker’srecommendations,�different�rivets�are�used.
Types�of�rivets�used�for�vehicle�repairsinclude:
• solid.• self-piercing.• blind.
Refer�to�Module�2,�"Demonstration:�RivetTypes"�for�an�example�of�different�rivettypes.
Module�2�-�Attachment�ProcessesTextbook
Adhesive�Bonding 36
Dissimilar�metals�contribute�to�galvanic�corrosion.
Considerations�for�using�rivet�bondingattachment�processes�include:
• no�heat-affect�zone.• acceptance�by�many�aluminum-
intensive�vehicle�makers.• using�rivets�and�adhesives�in�place
of�spot�welds.• protection�against�galvanic
corrosion.• the�need�for�special�tools�when
installing�rivets.• using�the�recommended�adhesive
for�aluminum.• the�availability�of�rivets,�and�where
to�purchase�them.�Audi�is�anexample�of�one�vehicle�maker�thatsells�rivets�through�their�dealerparts�departments.�Dependingon�the�vehicle,�repair�location,and�recommendation,�rivet�size�iscritical.
Pneumatic�tools�and�bucking�bars�are�used�forseating�solid�rivets.
Some�general�rivet�installation�toolsinclude�air�hammers,�bucking�bars,�andother�types�of�pneumatic�installationtools.
When�selecting�tools�for�installing�rivets,the�vehicle�maker�may�have�specificrecommendations.�There�may�also�beattachments�for�those�tools�that�should�bedesignated�for�aluminum-only�use.
Vehicle�makers�will�offer�repair�information�ifadhesives�are�allowed.
When�working�with�aluminum�it�may�berecommended�to�have�aluminum-onlydesignated�tools.�Having�separate�toolswill�help�eliminate�the�chance�for�crosscontamination.
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Adhesive�Bonding 37
There�may�also�be�vehicle�maker-specificpreparation�steps�for�some�aluminum-intensive�vehicles,�such�as�flame-treatingparts�and�the�application�of�specialprimers�before�adhesives�are�applied.Both�Jaguar�and�BMW�recommend�flame-treating�aluminum�parts�that�will�beadhesively�bonded.
Module�Wrap�Up
The�topics�discussed�in�this�moduleincluded:
• describe�different�types�of�weldbonding.
• describe�the�types�of�rivets�usedfor�rivet�bonding.
• explain�special�consideration�forusing�adhesives�for�aluminumrepair.
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Module�3�-�Two-PartAdhesive�Bonding
Repairs
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Adhesive�Bonding 41
Part�Removal�And�Cleaning
The�learning�objectives�for�this�moduleinclude:
• explaining�the�considerations�forseparating�panels.
• describing�when�primers�may�berequired.
• preparing�parts�for�adhesivebonding.
• describing�how�attached�partsshould�be�moved�once�attached.
A�variety�of�companies�offer�automotive�adhesives.
Two-part�adhesives�are�available�from�thevehicle�maker�or�from�the�aftermarketproduct�suppliers.�When�choosing�anadhesive,�refer�to�the�recommendationsfrom�the�vehicle�maker.
Personal�SafetyAlways�wear�leather�gloves�and�safetyglasses�when�using�heat�to�removebonded�panels.
Also,�wear�an�appropriate�NIOSH-approved�organic-vapor�respirator,�orsupplied-air�mask�in�areas�that�are�notwell�ventilated,�or�in�areas�where�smokecan�be�generated�from�heating�parts.When�sanding�cured�adhesive,�wear�aparticulate�respirator.
Vehicle�ProtectionOpen�flames�are�not�recommendedfor�removing�bonded�panels�due�to�thepotential�fire�hazard.
An�epoxy�or�acrylic�adhesively�bondedpanel�has�a�smaller�bond�line�than�a�one-part�urethane�adhesive�bond�line.�Toremove�an�epoxy�or�acrylic�adhesivelybonded�panel�with�heat:
1. Remove�any�welds�or�mechanicalfasteners.
2. Grind�the�outer�edge�of�the�flangeto�separate�the�inner�and�outerpanels,�as�required.�Panels�thattypically�require�grinding�forremoval�include�door�skins�andquarter�panels.
3. To�speed�the�removal�process,heat�the�bonded�area�of�thedamaged�panel�with�a�flamelessheat�source�up�to�400°F.�As�theadhesive�gets�warmer,�its�strengthand�bond�will�weaken.�Heatingabove�400°F�may�weaken�high-strength�steels�and�aluminum.Weakening�occurs�from�the�high
Module�3�-�Two-Part�Adhesive�Bonding�RepairsTextbook
Adhesive�Bonding 42
heating�temperatures.�Separate�thebonded�panels�after�the�adhesivehas�been�sufficiently�heated.
Flanges�are�cleaned�to�offer�a�sound�substrate�forbonding.
For�bonding�procedures�that�use�epoxyor�acrylic�adhesives,�remove�all�of�theoriginal�adhesive,�and�clean�the�matingflange�area�using:
• a�plastic-coated�abrasive�wheel�toremove�any�remaining�adhesive,corrosion,�E-coat,�or�othersubstances.
• the�recommended�grit�sandpaperto�remove�the�weld�nuggets�andgalvanizing.�Do�not�use�grindingtools�that�may�reduce�metalthickness.
Though�not�the�rule,�many�adhesivemakers�recommend�applying�metaladhesives�to�properly�prepared�baremetal.
When�attaching�replacement�panels�withadhesives,�Audi�recommends�cleaningthe�E-coat�surface�of�the�bond�area�onthe�replacement�panel�only.�Accordingto�Audi’s�recommendation,�do�not�scuff
or�remove�the�E-coat�on�the�replacementpanels.
After�panel�removal�and�cleaning,straighten�the�mating�flanges�to�create�aflat�bonding�surface.
Clean�bare�metal�with�wax�and�grease�remover(left).�Apply�the�primer�recommended�by�theadhesive�maker�(right).
During�the�panel�removal�process,�themating�surfaces�may�have�been�scratched.If�called�for�by�the�adhesive�maker,�coverscratches�with�a�corrosion-resistantprimer.
Depending�on�the�adhesive,�the�adhesivemaker�may�recommend�applying�acorrosion-resistant�primer�to�the�bondingarea�of�the�panels.
Regardless�of�the�bonding�process�beingdone,�always�refer�to�the�technicaldata�sheet�and�follow�the�specific�stepsprovided.�When�choosing�a�corrosion-resistant�primer,�refer�to�the�adhesivemaker�for�the�recommended�type�ofproduct�to�use.
Module�3�-�Two-Part�Adhesive�Bonding�RepairsTextbook
Adhesive�Bonding 43
Refer�to�“Video:�Panel�Removal�AndFlange�Preparation”�in�the�presentation.This�video�shows�how�a�damaged�doorskin�is�removed�and�a�replacement�doorskin�is�installed.
Preparation�For�Part�Attachment
Test�fitting�a�part�may�require�clamping.
When�preparing�a�replacement�part:
• test-fit�the�part�dry�first�to�ensurethe�part�fits�correctly�and�that�anyother�necessary�repair�processesare�done.
• mark�the�replacement�part�for�anyrequired�cutting�or�trimming.
• depending�on�the�adhesiveused,�the�E-coat�may�need�to�beremoved.�Factory�replacementparts�have�a�factory-applied�E-
coat.�Depending�on�the�adhesivemaker’s�recommendation,�the�E-coat�may�require�removal.
Adhesive�makers�who�recommend�leavingthe�E-coat�intact�may�suggest�wiping�thebond�area�with�wax�and�grease�removerand�scuffing�the�E-coat�before�applyingthe�adhesive.
Before�using�adhesives,�read�and�followeach�technical�data�sheet�regardingproduct�usage.�Even�when�using�twodifferent�products�from�the�samecompany,�the�usage�recommendationscan�be�different.
Clean�the�bond�area�immediately�before�applyingthe�adhesive.
When�preparing�a�flange�area�forbonding:
• clean�the�bonding�area�with�waxand�grease�remover.�Use�wax�andgrease�remover�on�the�primed�andbare�metal�areas�being�bonded.Porous�substrates�like�sheet-molded�compound,�fiberglass,�orcarbon�fiber�should�not�be�wipedwith�solvent.�This�is�because
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Adhesive�Bonding 44
the�fibers�in�the�part�will�causecleaning�agents�to�be�absorbed�orwicked�into�the�part,�which�canresult�in�a�poor�adhesive�bond.
• scuff�or�strip�the�E-coat�in�theareas�to�be�bonded.
• clean�the�prepared�area�withcompressed�air.
• mark�and�drill�or�punch�anynecessary�plug�weld�holes.
• mark�and�prepare�the�spot�weldlocations.
• mark�and�drill�or�punch�any�rivetbonding�locations.
Whenever�working�with�adhesives,�alwaysfollow�the�information�contained�in�thetechnical�data�sheets.
Refer�to�Module�3,�"Demonstration:Preparing�The�Part�And�Flange"�for�anexample�of�preparing�the�replacementpart�and�the�flange�area.
After�applying�a�corrosion-resistant�primer,�scuff�theprimer�with�a�scuff�pad.
When�using�an�adhesive�that�does�nothave�corrosion-resistant�properties:
1. Clean�the�bond�area�with�wax�andgrease�remover.
2. Apply�a�corrosion-resistant�primeraccording�to�the�adhesive�maker’srecommendations.�It�is�importantto�also�check�the�adhesive�maker’srecommendations�regarding�whichprimer�should�be�used.
3. Scuff�the�primer�with�a�scuff�pad.4. Remove�the�sanding�dust�and
debris�with�clean,�dry�compressedair.
Maintain�a�uniform�adhesive�bead�duringapplication.
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Adhesive�Bonding 45
When�applying�the�adhesive,�be�aware�ofthe�recommended:
• bond-line�thickness.• work�time.• clamp�time.• handling�time.• cure�time.
Attachment�Considerations
Leave�the�clamps�attached�while�the�adhesive�cures.
When�attaching�adhesively�bondedparts:
• assemble�the�parts�and�clampthem�into�position�so�they�do�notmove.
• reposition�the�parts�if�necessaryby�sliding.�If�a�part�is�lifted,�airbubbles�can�become�trappedinside�the�adhesive.�If�the�partsare�lifted,�the�adhesive�must�beremoved�and�reapplied.
• secure�the�mating�parts�as�soonas�possible.�Some�tools�thatcan�be�used�for�securing�panelsinclude�clamps,�locking�pliers,and�fasteners�such�as�clecos,rivets,�or�threaded�fasteners.
Refer�to�Module�3,�"Demonstration:Preparation,�Application,�AndAttachment"�for�an�example�of�cartridgepreparation,�applying�adhesive,�and�partattachment.
Clamps�also�help�create�quality�spot�welds.
If�a�part�is�not�being�attached�usingadhesives�only,�some�additionalattachment�methods�may�include:
• weld�bonding.�When�weldbonding,�the�adhesive�can�be�wetor�cured.
• rivet�bonding.�When�rivetbonding,�the�adhesive�must�bewet.
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Adhesive�Bonding 46
Clean�squeezed-out�adhesive�before�it�cures.
Following�panel�attachment:
• clean�any�excess�adhesive�byscraping,�grinding�with�a�plastic-coated�abrasive�wheel,�or�by�usinga�towel�dampened�with�adhesiveremover.�Do�not�apply�adhesiveremover�directly�to�the�bondedpart,�as�doing�this�can�weaken�thestrength�of�the�bond.
• begin�the�preparation�steps�forrefinishing.
Module�Wrap�Up
The�topics�discussed�in�this�moduleincluded:
• separate�panels.• when�to�use�primers.• parts�preparation.• adjust�attached�parts.
Module�4�-�One-PartAdhesive�Bonding
Repairs
This�page�is�intentionally�left�blank.
Module�4�-�One-Part�Adhesive�Bonding�RepairsTextbook
Adhesive�Bonding 49
Part�Removal�And�Cleaning
Learning�objectives�for�this�moduleinclude:
• describing�methods�for�removingparts�that�are�attached�using�one-part�adhesive.
• explaining�the�processes�forpreparing�a�one-part�adhesive�bed.
• describing�the�processes�forpreparing�a�replacement�part�forone-part�urethane.
One-part�adhesives�are�available�from�manyadhesive�makers.
One-part�adhesives�are�available�fromthe�vehicle�maker�or�from�the�aftermarketproduct�suppliers.�When�choosing�anadhesive,�refer�to�the�recommendationsfrom�the�vehicle�maker.
Using�a�cold�knife�is�one�of�the�most�effective�toolsfor�cutting�urethane.
Personal�SafetyWhen�using�heat�to�remove�bondedpanels,�wear�an�appropriate�NIOSH-approved�organic�vapor�respirator�orsupplied�air�mask.
Vehicle�ProtectionNo�open�flame.
To�remove�a�urethane-bonded�panel:
1. Remove�any�welds�or�mechanicalfasteners.
2. Cut�the�adhesive�to�separatethe�parts,�while�leaving�a�thinurethane�bed�on�the�existing�part.An�option�is�to�heat�the�bondedarea�of�the�damaged�panel�with�aflameless�heat�source�up�to�400°F.If�smoke�is�generated�when�theadhesive�is�heated,�unsafe�levelsof�methylene�diisocyanate�can�bepresent.�Methylene�diisocyanatemay�release�toxic�fumes.�If�thisoccurs,�ventilate�the�work�area,and�stop�heating.
3. Remove�the�bonded�panels.
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Adhesive�Bonding 50
Isopropyl�alcohol�is�the�recommended�cleaner�whenpreparing�body�panels�for�one-part�urethane.
For�attaching�replacement�parts�using�aurethane�bonding�procedure:
• clean�any�bare�metal�repair�areaswith�wax�and�grease�remover�toremove�any�contaminants.�Donot�contaminate�the�urethanebed�with�cleaning�solvents.Contaminating�a�urethane�bed�canaffect�the�strength�of�the�bond.
• trim�any�loose�adhesive�and�theurethane�bed�to�a�uniform�heightimmediately�before�attaching�thereplacement�part.�This�is�becauseurethane�adhesive�cross-links�tothe�existing�urethane�bed.�If�afreshly�trimmed�adhesive�bed�isleft�exposed�too�long,�the�bed�willbecome�contaminated�which�maycompromise�the�strength�of�thebond.
Cover�all�scratches�with�a�corrosion-resistant�primer.
During�the�panel�removal�process,�themating�surfaces�may�have�been�scratched.If�called�for�by�the�adhesive�maker,�coverthe�scratches�with�a�corrosion-resistantprimer.�Always�allow�primers�to�fullycure.
Regardless�of�which�bonding�processis�being�followed,�always�refer�to�thetechnical�data�sheets�and�follow�the�stepsprovided.
Most�adhesive�makers�recommend�usinga�two-part�corrosion-resistant�primer�inareas�where�adhesive�will�be�used.�Whenapplying�a�corrosion-resistant�primer,�referto�the�recommendation�from�the�adhesivemaker.
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Adhesive�Bonding 51
Preparation�For�Part�Attachment
Some�roofs�are�secured�with�adhesive�and�threadedfasteners.
When�preparing�a�replacement�part:
• mark�the�replacement�part�for�anycutting�or�trimming.
• test-fit�the�part�to�ensure�it�iscorrect.
• depending�on�the�adhesiveused,�or�the�vehicle�maker’sprocedure,�clean�the�bond�areausing�a�cleaner�that�is�compatiblewith�urethane�adhesive.�Whenreplacing�the�roof�on�the�SaturnVUE,�isopropyl�alcohol�is�therecommended�cleaner�for�thebonding�area�of�the�replacementpart.
• if�necessary,�use�clean,�drycompressed�air�for�removingcontaminants�from�the�bondingarea.
• additional�attachment�methodssuch�as�threaded�fasteners�may�beused.
• read�and�follow�the�technical�datasheets�regarding�product�usage.
Adhesive�beads�of�one-part�adhesive�are�larger�thantwo-part�adhesive�beads.
When�applying�the�adhesive,�be�aware�ofthe�recommended:
• bond-line�thickness.• work�time.• clamp�time.• handling�time.• cure�time.
Attachment�Considerations
Leave�the�clamps�attached�while�the�adhesive�cures.
When�attaching�adhesively�bondedparts:
1. Attach�the�part.
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Adhesive�Bonding 52
2. Reposition�the�parts�if�necessaryby�sliding.�If�a�part�is�lifted,�airbubbles�can�become�trappedinside�the�adhesive.�If�parts�arelifted,�the�adhesive�must�beremoved�and�reapplied.
3. Secure�the�mating�parts�as�soon�aspossible�with�clamps�or�fasteners.
Exterior�trim�is�attached�after�the�adhesive�has�cured.
Following�panel�attachment:
• clean�any�excess�adhesive�byscraping,�grinding�with�a�plastic-coated�abrasive�wheel,�or�by�usinga�towel�dampened�with�adhesiveremover.�Do�not�apply�adhesivesolvent�directly�to�the�bonded�partbecause�the�solvent�can�weakenthe�strength�of�the�bond.
• body�filler�can�be�appliedfollowing�the�required�clamping�orhandling�time.
• the�part�can�be�prepared�forrefinishing.
Refer�to�“Video:�Attaching�A�Urethane-Bonded�Part”�in�the�presentation.This�video�shows�how�proper�panelattachment,�adjustment,�and�clampinghelps�to�ensure�a�strong�bond�and�allowsfor�the�proper�curing�process�to�occur.
Module�Wrap�Up
The�topics�discussed�in�this�moduleincluded:
• remove�parts�that�are�attachedusing�one-part�adhesive.
• prepare�a�one-part�adhesive�bed.• prepare�a�replacement�part�for
one-part�urethane.
IntroductionObligations To The Customer And Liability
Module 1 - Adhesive Bonding MaterialsUsing AdhesivesAdhesive And Gun TypesModule Wrap Up
Module 2 - Attachment ProcessesAdhesive BondingWeld BondingRivet Bonding Steel VehiclesRivet Bonding Aluminum VehiclesModule Wrap Up
Module 3 - Two-Part Adhesive Bonding RepairsPart Removal And CleaningPreparation For Part AttachmentAttachment ConsiderationsModule Wrap Up
Module 4 - One-Part Adhesive Bonding RepairsPart Removal And CleaningPreparation For Part AttachmentAttachment ConsiderationsModule Wrap Up