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METAL FORMINGMETAL FORMINGMETHODSMETHODS

METAL WORKINGMETAL WORKING

•• Mechanical: To bring the metal into desiredMechanical: To bring the metal into desiredshape, generally by hammeringshape, generally by hammering

•• Chemical: To change the surfaceChemical: To change the surfaceappearance or to join pieces as in soldering.appearance or to join pieces as in soldering.

•• Embossing: To increase the surface byEmbossing: To increase the surface byhammering the metal into thin sheet andhammering the metal into thin sheet andcovering the modeled object made of claycovering the modeled object made of clayor carved wood.or carved wood.

SHAPING OF METALSHAPING OF METAL

•• Copper and its alloys can be shaped byCopper and its alloys can be shaped byrepeated hammering and annealing. It canrepeated hammering and annealing. It canbe hammered both hot or cold.be hammered both hot or cold.

•• Iron and its alloys can be forged only whenIron and its alloys can be forged only whenhot. Cooling rate is very critical for thehot. Cooling rate is very critical for thestrength of the alloy.strength of the alloy.

MECHANICAL SHAPING OFMECHANICAL SHAPING OFSHEET COPPERSHEET COPPER

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METAL FORMING BY HAMMERINGMETAL FORMING BY HAMMERING

SHAPING SILVERSHAPING SILVERANCIENT LATHEANCIENT LATHE

Used in shaping Bronze vessels by mechanicalApplication of force by using a lathe (torna)

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SHEET METAL DECORATIONSHEET METAL DECORATION

FORGING HAMMERSFORGING HAMMERS CASTING METALSCASTING METALS

•• Open moldsOpen molds

•• Piece moldsPiece molds

•• Hollow castingHollow casting

•• Lost wax castingLost wax casting

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OPEN MOLD CASTINGOPEN MOLD CASTING

PREPARATION OF COPPERPREPARATION OF COPPERBEFORE CASTINGBEFORE CASTING

•• Blister copper is remelted in a crucible toBlister copper is remelted in a crucible tokeep surface area minimum and avoidkeep surface area minimum and avoidcontact with air.contact with air.

•• Residual inclusions float to the surface andResidual inclusions float to the surface andare removed off as a dross.are removed off as a dross.

•• The molten metal is polled by unseasonedThe molten metal is polled by unseasonedwood to reduce copper oxide that may havewood to reduce copper oxide that may haveformed during melting back to metalformed during melting back to metal

MOLDMOLD

•• Can be made from stone, refractory clay orCan be made from stone, refractory clay ormetal.metal.

•• It has to be perfectly dry, otherwise vaporsIt has to be perfectly dry, otherwise vaporsevolved may blow holes in the metal.evolved may blow holes in the metal.

•• Mold faces are given a dressing of soot,Mold faces are given a dressing of soot,wood ash, flour or animal fat to ensure awood ash, flour or animal fat to ensure agood surface to the casting.good surface to the casting.

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EGYPTIAN CASTING OFEGYPTIAN CASTING OFTEMPLE DOORSTEMPLE DOORS

Temple doorTemple door

Cu IngotSn Ingots

OPEN MOLDS FROM TARSUSOPEN MOLDS FROM TARSUS

OBJECTS THAT CAN BE MADEOBJECTS THAT CAN BE MADEBY OPEN MOLD CASTINGBY OPEN MOLD CASTING

AXE SAMPLES CAST BYAXE SAMPLES CAST BYOPEN MOLDOPEN MOLD

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PIECE MOLD CASTINGPIECE MOLD CASTING CASTING A SPEAR HEAD BYCASTING A SPEAR HEAD BYUSING PIECE MOLDUSING PIECE MOLD

EXAMPLES OF PIECE MOLDEXAMPLES OF PIECE MOLDCASTINGCASTING

CASTING AN AXE WITH ACASTING AN AXE WITH ASHAFT HOLESHAFT HOLE

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CASTING SHAFT HOLE AXECASTING SHAFT HOLE AXE

FATIHFATIH’’S CANNONSS CANNONS

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HOLLOW CASTING BYHOLLOW CASTING BYPIECE MOLDSPIECE MOLDS

Post to holdclayfor model

Clay builds up Approximate shape isreached

Rigid profile givesthe final form

The clay model dries and hardes

The outer mold is madein sections. They are fired and reassembledafter shaving the surface to allow spacefor the metal

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Molten bronze ispoured into mold.It generally containsabout 3% lead

The outer moldand the inner core is removed afterhalf hour

Metal Casting of ChinaMetal Casting of China’’s s ShangShangDynasty (17-11th century BC)Dynasty (17-11th century BC)

PIECEPIECEMOLDMOLD

CASTINGCASTING

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CASTING BY PIECE MOLDCASTING BY PIECE MOLD

CHINEESE BRONZESCHINEESE BRONZES

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LOST WAX CASTINGLOST WAX CASTING

LOST WAX CASTINGLOST WAX CASTINGLOST WAX CASTINGLOST WAX CASTING

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HOLLOW LOST WAX CASTINGHOLLOW LOST WAX CASTING

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GRANULATIONGRANULATION BRAZINGBRAZING

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Au-Ag-Cu Ternary Phase DiagramsAu-Ag-Cu Ternary Phase Diagrams METAL EMBOSSINGMETAL EMBOSSING

Gold can be beaten to a foil 50 - 100 nm (10Gold can be beaten to a foil 50 - 100 nm (10-9-9m) (aboutm) (about250 - 500 atoms in thickness. Strip of gold 2 mm in250 - 500 atoms in thickness. Strip of gold 2 mm inthickness can be elongated to about 186,000 timesthickness can be elongated to about 186,000 timesreduction in size (99.9996 %) reduction in size (99.9996 %)

SURFACE ENRICHMENTSURFACE ENRICHMENT

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MERCURY GUILDINGMERCURY GUILDING•• Mix Gold or silver withMix Gold or silver with

mercury to form anmercury to form anamalgamamalgam

•• Apply the amalgam on theApply the amalgam on thesurface of copper objectsurface of copper object

•• Heat the object to evaporateHeat the object to evaporatethe mercurythe mercury

•• Thin layer of gold or silverThin layer of gold or silvercoat will remain on coppercoat will remain on copperobject.object.

INDUSTRIAL BRONZE CASTINGINDUSTRIAL BRONZE CASTING

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IRON CASTINGIRON CASTING

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