Cire perdue

Properties2
tagsconcept, craft, metalwork, casting, goldsmithing, brasswork, sumatra, technical-vocabulary
aliasesà cire perdue, lost-wax casting, the cire perdue process, Indonesian lost-wax casting, the wax-casting process, cire-perdue, was-casting, lost-wax method

8 min read

Cire perdue — French for “lost wax” — is the casting process, recorded in Prof. T. J. Bezemer’s 1933 plate-atlas *Indonesische Kunstnijverheid* under its French name à cire perdue, by which an indigenous Indonesian goldsmith or brass-caster produces a metal object by modelling the object in wax, enclosing the wax model in a clay mould, melting out the wax to leave a hollow mould, and pouring molten metal into the hollow to replace the wax. The process is the standard technique of Indonesian metalwork, used for both the gold- and silverwork documented in § H of the Bezemer atlas and the brasswork documented in § F; it is the technical frame within which the Atjeh goldsmiths’ alternative *soeasa* wrapping technique is defined, and the technique by which the Atjeh sirih-bowl and food-tray of plate 172 and the standing brass lamps of plate 174 were cast.

The two variants of the process

Bezemer’s Inleiding (p. 11) describes two variants of the cire perdue process, as practised in the Indonesian archipelago. In the first variant, the wax model is enclosed in a clay mould, the mould is dried, and the mould is then heated in an oven (een oventje) so that the wax melts and flows out through an opening made for the purpose at the bottom of the mould — leaving a hollow mould that can be filled with molten metal. In the second variant, the molten metal is poured through an opening at the top of the mould directly onto the wax model inside: the metal, being hotter than the melting-point of the wax, melts and displaces the wax, which flows out through the bottom opening as the metal fills the mould. The two variants produce the same result — a hollow clay mould containing a cast-metal object — but the second variant combines the wax-melting and metal-pouring in a single operation.

In both variants, the clay mould must be broken to release the cast-metal object: “Om het metalen voorwerp uit den kleivorm vrij te maken moet deze vernietigd worden en kan dus slechts eenmaal gebruikt worden” — “To release the metal object from the clay mould, the mould must be destroyed, and so can be used only once.” This is the defining feature of the cire perdue process: each cast is unique, because the mould is destroyed in the casting. The process is therefore unsuitable for mass production but well suited to one-off craft production — which is why it remained the standard Indonesian technique for fine metalwork into the late colonial period.

Hollow casting

Bezemer notes that the cire perdue process can be used to cast not only solid objects but also hollow ones. The hollow-casting variant is described with a simple example: “Wanneer men, om een eenvoudig voorbeeld te noemen, een koperen kom wil gieten, kneedt men een vorm van klei ter grootte van den inhoud dien men aan de kom wil geven. Deze klei wordt bekleed met een laag was ter dikte van de wanden van de te maken kom en de was weer met houtskoolpoeder bekleefd, waarna ook de buitenkleilaag wordt aangebracht” — “When one wishes, to take a simple example, to cast a copper bowl, one kneads a clay form the size of the interior one wishes the bowl to have. This clay is covered with a layer of wax the thickness of the walls of the bowl to be made, and the wax is again coated with charcoal powder, after which the outer clay layer is applied.” The inner clay form serves as the kern (core) of the hollow casting; the wax layer between the core and the outer mould is the wax model of the bowl’s wall; and when the wax is melted out and the metal poured in, the metal fills the space between the core and the outer mould, producing a hollow bowl with the inner clay core still inside. The core is then broken out (or remains inside, in some traditions), leaving the hollow metal bowl.

The hollow-casting variant is the one used for the larger brass objects of the Bezemer atlas — bowls, pots, lamps — and is the variant most relevant to the Atjeh brassware documented in plates 172 and 174. The Atjeh sirih-bowl and food-tray and the standing brass lamps of Northern and Central Sumatra would have been cast by this hollow-casting variant of the cire perdue process.

Materials: brass and bronze

Bezemer notes that the metal used in Indonesian cire perdue casting is, in the late colonial period, messing — brass, an alloy of copper and zinc. Older pieces, however, are of brons — bronze, an alloy of copper and tin: “Oudere stukken echter zijn ook van brons, een alliage van rood koper en tin” — “Older pieces, however, are also of bronze, an alloy of red copper and tin.” The historical shift from bronze to brass is, in the Indonesian metalwork tradition, a marker of the late-colonial period: the bronze-casting tradition of the older Indonesian polities (the bronze kettledrums or *moko’s, the bronze gongs of Broenei, the bronze figures of Java) had, by the late colonial period, largely given way to a brass-casting tradition that used cheaper, more readily available zinc in place of tin. The Atjeh brassware of the Bezemer atlas — the sirih-bowl of plate 172, the standing lamps of plate 174 — are of the later brass-casting tradition.

Surface decoration

After the cast object has been removed from the mould and polished, the surface decoration is added by ciseleer- en graveerwerk — chasing and engraving. The relief decoration, however, is already applied to the wax model — and so is cast in the metal — rather than being carved into the finished object. Bezemer notes: “De reliefs worden reeds vóór het gieten, dus op den vorm, aangebracht” — “The reliefs are already applied before the casting, that is, on the [wax] form.” The decoration of an Indonesian cire perdue cast object is therefore a combination of cast relief (applied to the wax model before casting) and chased-or-engraved detail (applied to the metal after casting). The ornament is drawn from the standard Indonesian repertoire: the human figure (on Java, in the form of the wayang type), animals, plants, and geometric figures.

Atjeh connection

The Atjeh connection of cire perdue is twofold. First, the process is the technique by which the Atjeh brassware of the Bezemer atlas — the sirih-bowl and food-tray of plate 172 and the standing brass lamps of plate 174 — was cast. The Atjeh brass-casting tradition is one of the regional Sumatran variants of the broader Indonesian cire perdue tradition. Second, the process is the technical frame within which the Atjeh goldsmiths’ *soeasa* wrapping technique is defined: the Atjeh goldsmiths chose the wrapping technique — wrapping a copper core with *soeasa* sheet — as an alternative to the cire perdue casting used by their Toba-Batak neighbours on Noord-Sumatra, and the contrast is documented by Bezemer precisely because the Toba-Batak cire perdue process had already been documented by J. E. Jasper en Mas Pirngadie in De Inlandsche Kunstnijverheid in Nederlandsch-Indië, Vol. IV, pp. 25–26.

The Atjeh-specific soeasa wrapping technique is, in this sense, a technical alternative to the cire perdue casting process: where the Toba-Batak goldsmiths cast their ornaments in one piece by the cire perdue method, using *rimbaga* wax for the model, the Atjeh goldsmiths built their ornaments by wrapping a copper core with soeasa sheet and heat-bonding the sheet to the core. The two techniques produce objects of similar appearance — gilded-copper ornaments — but by different methods, and the contrast is one of the regional variations within the broader Sumatran metalwork tradition.

Significance

For Atjeh’s history, cire perdue is significant principally as the technical frame within which the Atjeh metalwork tradition is defined. The process is the standard Indonesian casting technique, used for the Atjeh brassware of the Bezemer atlas; it is also the alternative to which the Atjeh goldsmiths’ soeasa wrapping technique is contrasted. The term cire perdue belongs to the same technical vocabulary as rimbaga (the wax-resin-fat compound used in the process), spinsbek / soeasa (the alloy used in the Atjeh alternative), granuleeren (the granulation technique of the Batak, Dyak and Timorese silversmiths), and filigraanwerk (the filigree technique of the Padangsche Bovenlanden) — a vocabulary that, taken together, constitutes the late-colonial Dutch technical lexicon for Sumatran metalwork, within which Atjeh metalwork is described as a regional variant.

See Also

Source

Indonesische Kunstnijverheid. Platen-Atlas met Inleiding van Prof. T. J. Bezemer (‘s-Gravenhage: N.V. tot Exploitatie van het Maandblad “Nederl-Indië, Oud en Nieuw”; ten Hagen’s Drukkerij en Uitgeversmaatschappij N.V., 15 October 1933), pp. 11, 13 (describing the à cire perdue process as used for Indonesian brasswork and goldwork). Universiteitsbibliotheek Vrije Universiteit, Amsterdam, LS 5411. See also De Inlandsche Kunstnijverheid in Nederlandsch-Indië, by J. E. Jasper en Mas Pirngadie, Vol. IV, pp. 25–26 (the source of Bezemer’s description of the Toba-Batak cire perdue process).

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