SolventWelding

Description

Students willlearntocorrectlyprepare,assemble, and solvent weldABSpiping.

LessonOutcomes

The student willbeableto:

•Accuratelycut plastic piping

•Prepare plastic pipingfor solventwelding

•Safely solventweldplasticpiping

Assumptions

Theeacher isfamiliar withthe tools, materials,andprocedures related to solventwelding.

Terminology

ABS:anacronymforacrylonitrilebutadienestyrene;themostcommonplasticpipeusedfordrainage, waste,andventing(DWV)inBritishColumbia.

Dryfit:atechniquecommonlyusedtoprepareforinstallationofpiping.Withdryfitinstallation,smallsectionsofpipeandfittingsarepushedtogetherwithout solvent cementso they can

beeasilydisassembled.Whensectionsofpipeareconfirmedtobecorrect,fittingsaredisassembledandbondedwith solventcement.

MaterialsSafetyDataSheet (MSDS):informationspecifictoanindividualproduct’ssafeusageandhandling.

Solventweld:theprocessofusingaliquidsolvent tochemicallybondplasticpipeandfittings.

WHMIS:commonlyusedacronymfor“WorkplaceHazardousMaterialsInformationSystem,”Canada’smethodforcommunicatinginformationregardingthesafehandlingandusageofmaterials.

EstimatedTime

2–8 hours

RecommendedNumberofStudents

Activities couldbedone individually or inpairs.

Thisworkis licensedunder aCreativeCommonsAttribution-NonCommercial-ShareAlike4.0InternationalLicenseunlessotherwiseindicated.

Facilities

Shop settingwithflat,stableworking surface (studentbenches). Access towater(hose)requiredfor testing.Solventwelding givesoff strongfumes. Good ventilationor anoutdoor areaisadvisable.

Thepreferred method of holding pipe for beginnersis achain vise available in portable(Figure1) or bench-top versions.Alternatively, a standardwoodvise or a flat surface uponwhich thepipe could be heldsecurelywould suffice.

Figure1—Portablechainviseforholding pipe

Tools

ABS pipecan be cutin severalways. The most common methodin industry isusingahacksawwitha14–18tooth blade. Alternatives include:

•Reciprocatingsaw

•Handsaw with mitre box

•Tubingcutter withplastic cutting wheel

•Mitre saw

•Plastic pipecutter (Figure 2)

Figure2—Ridgid FC-200capableofcuttingABS pipe up to2"

Materials

•Anassortment of 1½",2", and3"diameterABSpipe, dependingonactivity

•ABSsolvent cement (yellow),generically referredtoas glue.Technically,solvent cementis the correct term, asthe solventchemically softenstheplastic surfaces before bondingoccurs as the solventevaporates.

•ABS fittings (typeandquantitydepending on activity):45°bends,90°bends,22°bends;wyes,tees,caps,reducers,linecleanouts. See belowfor fittings commonly availableatplumbingwholesalers or retail outlets.

Figure3—ABS 45°.Thehub byhub 45 shownon the leftconnects two piecesof piping.The hub by spigot 45 shown on the right fits directly into another fitting (typically a wye).

Elbowsareavailableasfittings,meaningoneend can fit directlyintoanother fitting withoutadding further pipe.The45° elbowmayalso be referredtoas a⅛thbend,as45°represents ⅛thof a full circle (360°).

Figure4—ABS90°elbow / Figure5—ABStee
Also availableas fitting 90sandmay bereferredtoas¼bends. / Many combinationsof outletsizes areavailable. Notehowthe throat of thebranchdirectstheflowofwastemovingthroughthefitting.
Figure6—ABSwye / Figure7—ABSdoublewye
Figure8—ABSlinecleanout / Figure9—ABS p-trap.Asolidp-trap is pictured(allsolvent welded connections).
This fitting withitsremovableplugis amandatory part ofany drainage system.Theplug must belocated soitmay beremoved forinspection or cleaning ifablockageoccurs within the system. / Thetrapprovides a water seal thatpreventssewergas from coming into thelivingspace.Trapsareconnected belowbasins, showers, and bathtubs. The trapfor atoilet islocatedwithin thebowl, soap-trapdoes notneedto beconnected.
Fixturetailpiece
Sewergascan’tseepintohome
Watercaughtintrapcreatesseal
Clean-outplug /
Figure10—Acutawayviewof ap-trap. Note thatp-traps mayhave acleanoutplug toallow forcleaning or inspectionof thepiping.Asolid p-trapisusedif thetrap islocated inlocationthatisnot easilyaccessible (for example, acrawlspace). / Figure11—ABSwaterclosetfloorflange

Theflangemust be securely attached tothe floor usingbrassscrews.Theflangethenprovidesa sturdyplatform uponwhich a toilet(alsoknown as awater closet)canbe fastened. Brassscrews, bolts,andwashersareused below a toiletas theyare highly resistanttocorrosion.

Figure12—ABSbushing

Bushings fit inside a fitting tofacilitate a reductioninthesizeofpiping.

Resources

Solventweldingliteratureandlinktoonlinetrainingsystem;generalinformationwitha

specific focus on two-stagesolvent welding for PVC pipe

ABSsolventweldingvideo

ABSsolventweldinginformationsheet

WHMISinformationandresources

MSDSforABSsolventcement

Activity 1:CutPipeSquarelyandAccurately

Havestudentscut10 pieces ofABS1"long.Thestudents can layoutthe pieces flat on a tabletocheck for consistencyandstraightness. Industry tolerance is typically+/–⅛" accuracy oflength. Asdescribedinthe“Tools” section, many methods of cuttingABS are available.Theteacher couldhavestudents practise several methods.Inaddition, cutting withahacksaw canbepractised in several positions. Plumbersshould beable tocutpipe accurately in whateverenvironmentthey are working. Thisincludes trenches,crawlspaces, or even seated infrontof acabinet. Students could practiseby supportingthe pipewith achain vise,ladder, oreven withnosupport (seated on thefloor)(Figure13).

Burrson theinside and outsideedgesof pipe should be removedbyhand, rag,utility knife, orfile. A de-burring tool could also be used.Outside burrs interferewiththe insertion ofthepipeintothe fitting, whileinside burrs mayinterferewiththe free flowofmaterialsthroughthepipe(Figure14).

Figure13—CuttingABS with only aladder supportcanbe challenging at first. / Figure14—CuttingABSin aseatedposition

Figure15—Ridgid de-burring tooltoremove burrs on insideand outside edgesof pipe

A wraparound(emery clothor sandclothare cost-effectivesubstitutes)usedto markaperpendicular guideline provides a useful techniqueforbeginners to mark their cuts.

Figure16—Positioningawraparound tomarkthecut line.

Students align thewrap andmark the pipewith pencil, permanentmarker,or paintmarker. Thismethodisusefulon larger diameterpiping, which studentstend tocutcrookedly.Themarkingsgive studentimmediate feedback todetermine ifthey are maintainingastraightcut.

Figure17—Markingasquareline helps novices toproduce squarecuts.

Activity 2:CutABSPipe with ReciprocatingSaw

Have students cut10pieces of ABS, each1"long, using areciprocatingsaw (Figure 18).Students must weareye protectionand keep theguidetighttothe pipe. A12–18tooth bladewillquicklyremove cutmaterialand reducethe amount ofmelted material.Burrs producedbythismethodof cutting tendto be more difficult toremove, so a file or utilityknifeislikelyto beneeded.

Figure18—ReciprocatingsawscutABSpipeveryquickly.

Activity3:AssemblePiping

Havestudentsassemble a smallsystemof fittings andpipetogivendimensionsusingABSsolventcement. See theABS starter drawing(Figure19)asanexample.Pairsofstudentscould buildletterstospelltheirschool’sname.Therearealsomanygamesinvolvingthrowingbeanbags or rings that couldbe built.

Note: Assembled fittings andpipe can only be disassembledwithinminutes ofsolventwelding.Within a period of24hours,maximumbondingstrength occurs, and fittings become extremelydifficult toremove from pipe.

•Have studentswork withapartner tocreate their assignedletter.

•Allletters mustbe amaximumof 16"talland 12"wide.

•Studentsmustdry fit allpipeand fittings beforetheyare permitted tosolventweld.

Figure19—SampleABSstarterproject

Activity4:Sculpture

Havestudentsdesignandcreateanobject from ABSpipeandfittings. See Figure20asanexample.

•Students sketch anobject they wishtoconstruct,including dimensions. Alternatively, an open-endeddesigntechnique couldbeemployed.Forexample,alistof fittings and a givenlengthofpipe could be madeavailable to each student.

•Studentscutpipeand dry-fit fittings.Forthepurposesof disassemblyand modellingcorrect solventwelding

technique,a smallbrush with whitegrease canbeused.Thegrease serves as alubricantthatwill make thefittings mucheasiertodisassemble or reuse.Thegreasemust beremoved witha rag before solventweldingoccurs.

Figure20—SampleABSsculpture

PartsList

• (4)1½"45°elbows

• (4)1½" tees

• (4)1½" cross

• (6)1½"90°elbows

Procedure

•Have studentssketch a3-Dobjectthat will bebuiltwithABSpipeandfittings.

•Studentsare permitted a maximumof20 fittingsand6' ofpipe.

•Studentsmusthave theirdesigns approvedbytheteacherbefore constructing their sculptures.

Figure21—AsculptureusingABSfittings and pipe

Activity5:IntegratedActivity

Students assemble drainagepiping forusein draining awashroom. See Figure22 as anexample.

Plan view

3" Sanitaryconnection

Figure22—ABSrough-in

•Theteacherwill explain to studentsthat theywillbe assisted indesigning adrainingsystemtoaccommodateall fixtures.

•Have studentsdraw the drainage system,including thepipe size (Figure23).

Figure23—ABSrough-in(key)

Teacher Notes

•See Figure 24 for furtherdetail.

•2"toLAVis necessary forventingofother fixtures.

•Indicateddimensionsareavailable from manufacturer’s specifications online.

Notes/Specifications

Fixtureschedule(seemanufacturer’sdocumentationforlocationofdrains)

•WC – American StandardChampion Model 5325010

•LAV –AmericanStandardStudio Above Counter Model0621001

•SH–Maax CyreneModel300001

WallSchedule

•2×4" wall with½" drywall(actualwidthof wall willbe 3½"+drywall)

2-1½"45°elbows1½"cap(p-traptobe

addedafterwatertest)

1½"forvent

2-2"45°elbows

2"linecleanout

2"×1½"×1½"tee1½"90°elbow

1½"cap(p-traptobeaddedafterwatertest)

1½"2"

3"3"

3"doublewye

3"×2"bushing(toLAV)3"×1½"bushing

and45°elbow(toshower)

2-3"45°

3"90°elbow

Teacher Notes

Figure24—Roughinisometric

•Dependingon time available, itmaybe easierto provide studentswith all dimensions andalayout ofpiping.

•Pipingmust be supported so itwillnotmovewhenfilledwithwater. A common methodforthis istheuse of ½" strapiron (Figure25).

•Horizontalpipingshould begraded at ¼" perlinear footof pipe.An approximationofone-quarter bubble on a levelwouldsuffice(Figure26).

•Whenpipingiscompleteand openendsarecapped, a watertestcanbeperformed. Thisinvolvesfillingthesystemwithwaterandcheckingforleaks.Thewatertestisconductedonall drainage systemsfor alocalinspector.

•Once a wallfinish(drywall or tile)iscomplete, fixtures including p-traps may be connectedtothedrainage system.

•Whenpipingiscompleteand openendsarecapped, a watertestcanbeperformed. Thisinvolvesfillingthesystemwithwaterandcheckingforleaks.Thewatertestisconductedonall drainage systemsfor alocalinspector.

•Once a wallfinish(drywall or tile)iscomplete, fixtures including p-traps may be connectedtothedrainage system.

Figure25—Strappingis acost-effectivewaytosupportpiping.

Use screwsthroughthe perforations tosupporthorizontalor vertical piping.

Figure26—Atorpedolevel canindicate horizontallevel, verticalplumb, and45° angle.

Somemodelscan alsoindicate grade (angle) ofpiping.Alevel showing approximatelyone-quarter of the bubble above horizontal canbeused as anapproximation of¼"per foot.

EvaluationGuidelines

Thestudent:

•Assemblespipeand fittings accuratelytogivendimensions.Suggestedtoleranceof ⅛".

•Cuts pipesquare.

•Assemblesjointscorrectly.

•Removesexcesssolventcement.

•Follows allsafety procedures.

•Assemblespipeand fittings so theyareableto hold water.