3第3章 (2/2)

【畅读更新加载慢，有广告，章节不完整，请退出畅读后阅读！】

bsp;

  

  

  
  
thathigh-qualityclayshouldbefineandfreeofparticles,uniforminhumidityandstronginplasticity;otherwise,finishedproductsarepronetocracking,bubblinganddeformation.Ifirstscreenedthepurchasedpotteryclaytoremovegravelandimpurities,thenrepeatedlykneadedandpuggedtheclay.Attheverybeginning,Iadoptedstiffgestureswithunevenkneadingforce,leavingalargeamountofairtrappedinsidetheclay.Underteachers'instruction,Imasteredthecrosskneadingmethod.Byrepeatedfolding,pressingandrubbing,airbubblesinsidetheclayweregraduallyexpelled.Afternumerouspractices,Ibecameskilledatthistechnique,andthetreatedclaywascompact,delicateandsoft,meetingthestandardforcastingproduction.
  

  

  
Withclaypreparationcompleted,thecorepartofthistraining?moldslipcastingwascarriedout.Prefabricatedplastermoldswereusedinthetraining.Plastermoldsfeaturegoodairpermeabilityandmoderatewaterabsorption,makingthemthemostcommonlyusedmoldmaterialforpotterycasting.Beforeoperation,Icleanedandfullydriedthemoldstopreventresidualimpuritiesfromaffectingtheflatnessoffinishedpieces.ThenIassembledandfixedthemolds,clampingthegapswithbucklestoavoidslurryleakageduringpouring.Next,Ipreparedceramicslipaccordingtotheproportionandstrictlycontrolleditsconsistency.Excessivelythickslipeasilycausesuneventhicknessofblanks,whileoverlythinslipresultsinlooseformingandincompleteblanks.
  

  

  
Afterpreparingtheslip,Ipoureditslowlyandevenlyintothemolds.Fastpouringwouldgenerateexcessiveairbubbles.Afterfillingthemolds,Iletthemstandfortenminutes.Relyingonthewaterabsorptionofplastermolds,anevenlayerofclayblankadheredtotheinnerwall.Afterwards,Ipouredouttheredundantslipandleftthemoldstostandanddryagainforpreliminaryshapingofblanks.Thisprocedurerequiredextremepatienceandprecisecontrol.Duringmyfirstattempt,improperstandingtimeledtouneventhicknessatthebottomandbumpyedgesafterdemolding.Afterobservingteachers'operatingrhythmrepeatedlyandrecordingkeyparameterssuchasstandingdurationandpouringspeed,Iadjustedmyoperationsmanytimesandfinallyproducedneatlyshapedblankswithuniformwallthickness.
  

  

  
Afterpreliminaryblankforming,theprocessesofblanktrimmingandairdryingfollowed.Thesemi-drystateistheoptimaltimefortrimming,whenblankshavecertainhardnesswhileremainingeasytotrimandshape.Iusedtrimmingknives,scrapersandothertoolstocarefullysmoothroughedges,airholesandunevenparts,polishassemblygaps,andrefinelinesandcontourstomaketheoverallshapemoresmoothandaesthetic.Trimmedblankscannotbefireddirectly;theyneedtobenaturallyair-driedinawell-ventilatedandcoolplaceinsteadofbeingexposedtodirectsunlight.Rapidwaterevaporationunderstrongsunlightwilleasilycausecrackinganddeformation.Followingteachers'requirements,Iplacedtheblankstoair-dryforthreed