Table of ContentHistory of Metal Casting through CivilisationsIn the expanse of South AsiaThe South Indian BronzesThe Tribal PracticeWhy is Bronze preferred for making Sculptures?The Nataraja and The Harappan Dancing GirlConclusion
Table of Content
History of Metal Casting through Civilisations
In the expanse of South Asia
The South Indian Bronzes
The Tribal Practice
Why is Bronze preferred for making Sculptures?
The Nataraja and The Harappan Dancing Girl
Conclusion
The Copper or Chalcolithic Age of the Indian subcontinent is as old as the Harappan Civilisation possibly having its connection with that of Mehergarh in Baluchistan in late sixth century BCE. Contemporaneous to Harappan civilization, the well-known copper technology of Middle East in Sinai and Far East in China constitute a glorious past of ancient history. With the decline of Harappan Civilisation, copper casting technology opened new frontiers in mainland India in second millennium BCE. Daimabad bronzes owing even a heavy cast piece of 29 kg bore the evidence. That was an achievement over Harappan technology for casting heavy statues. Other than the casting technology there are a few references of forging technology in excavation in Harappan sites. Other than small tools of boring drills, saws, nails but again some bun shaped ingots were reported by a number of archaeologists from Mohenjodaro and Lothal. In case of Eastern India earliest evidence of copper alloys were reported from Pandu Rajar Dhibi, Mangalkot, Bahiri, Chirand, Golbai Sasan and Senuwar. Thus, from earliest initiation from Neolithic-Chalcolithic transition, a continuation of copper, bronze and brass products were noted in eastern India through early historic period – from medieval and continuation of traditional processes in pre-industrial period.
It is likely that the majority of early tools and weapons, will have been cast in relatively simple single or double-piece moulds, usually of ceramic, but sometimes of stone. It might be thought that the more sophisticated process of lost wax casting would appear relatively late, but in some regions of the world such as South Asia it has a very long history, back almost to the inception of metallurgy itself. It is claimed that already by the 5th millennium BC the lost wax process was being used to cast armlets at the prehistoric settlement at Mehrgarh, now in Pakistan, making them the earliest lost wax artefacts known (Davey 2009). The armlets are of copper to which lead had been added. This in itself is of some significance suggesting deliberate alloying even at this early date, as quite small quantities of lead in a copper alloy can greatly increase the fluidity of the molten metal, and thus its ability to flow, filling confined and intricate spaces in a mould.
Lost wax castings are again encountered, somewhat later at the end of the fifth millennium BC, at Shahi-Tump, also in Pakistan. Moving onto the major early civilisations of north India, the Harappans, it is likely that the majority of their copper alloy tools and weapons, the flat axes, etc. were cast in single or two-piece clay moulds, but some pieces such as the famous dancing girl are almost certainly lost wax castings number of simple but heavy cast copper vessels are known. These could have been produced by piece moulding, lost wax or even sandcast. Both copper and bronze were used. The heavy, often clumsy and clearly unfinished copper castings that form the bulk of the material in the enigmatic copper hordes of the Doab and Bengal are all likely to have been cast in simple one or two-piece moulds.
Overall, in South Asia, through prehistory, the Mauryan Empire and beyond, relatively few lost wax castings have been found and it seems that their production was rather infrequent, certainly when compared with later periods. This was to change dramatically with the rise of both Buddhism and Hinduism in which the worship of idols played a significant part. From the Gandharan period on images were produced in prodigious numbers. Initially these were mainly of bronze but were increasingly replaced by brass. The figures were usually lost wax castings, initially mainly solid castings, but soon joined by hollow castings, which became prevalent particularly for the larger figures. By far the largest surviving figure is the famous Buddha found at Sultanganj, near to Nalanda, in Bihar, probably dated to the 6th or 7th century AD. It is of an impure copper containing several percent of iron.
The Sultanganj Buddha is apparently unique, but in the south of India the casting of major figures developed in the Pala and Chola cultures from about the 9th century AD onwards. These were made by the direct lost wax process and were usually solid. Major bronze casting has persisted through the centuries down to the present at centres such as Swamimalli in the Thanjavur District of Tamil Nadu. Now, many of the larger figures are hollow cast, especially those cast by the non-hereditary entrepreneur-owned foundries, although the hereditary sthapathi foundries still mainly produce solid castings. The early figures were of copper or of bronze with just a few percent of tin and sometimes lead as well. The use of bronze persisted for much longer in the south of India than in the north, and even now zinc only forms a minor component of the alloy along within and lead. Together with these major image-producing centres in the north and south of India there are the small scale tribal foundries, often impermanent, throughout much of India, producing a range of products, including images, usually in brass.
The bronzes images of southern India have attracted a large literature, and several studies of the casting processes as carried on at traditional centres such as Swamimalli have been made. The usual alloy in the past was of bronze often with some lead for the images from southern India It seems that from the post-medieval period zinc began to appear in the alloy along with tin and lead. Given the widespread use of scrap metal in the alloys the incorporation of zinc from scrap brass was inevitable. It was often decreed in texts, such as the 12th century Sri Lankan Sāripūtra text, that the images of deities intended for ritual purposes had to be solid castings, such as the famous 8th century Bodhisattva Tara, from Trincomalee, now in the British Museum. The hereditary casters of Swamimalli still mainly produce only solid castings. However, hollow castings were certainly not unknown in the past, especially for larger figures, as exemplified by the Sultanganj Buddha, and not just for reasons of economy as outlined above.
The dried and fired core is covered with sheets of wax of the required thickness and the fine modelling of the figure is performed. Alternatively, the limbs are moulded separately and then attached to the main torso with metal dowels in the core. An important distinction of the south Indian tradition is that the figure, no matter how complex, is cast as one, with the exception of the base. This is perhaps most remarkable in the Śiva Natarāja figures where the thin encircling prabhāvalī ring of fire is part of the main casting. For this a quite complex series of pouring and feeder channels are required. The wax is then invested with clay built up in layers. The first layer is of river silt and clay obtained from the River Cauvery, mixed with strained cow dung, and applied as a cream. When this has dried another layer is applied, this time a little stiffer and thicker. Then a mesh of iron wire is fitted around the mould and the outer layers of rough field clay built up around the mould. After drying for several days, the mould is placed in the casting pit. The major castings were, and continue to be cast lying face down, approximately horizontally but with the head of the statue slightly lower. The figure had been cast lying face down with the metal channelled straight to lowest part of the casting, such that the smith could judge that the mould had been successfully filled when metal appeared in the riser channels at the other end. In this instance the metal set before it had completely filled the upper part of the mould and so even before breaking the mould the smiths would have known there were serious problems which in this instance, they were unable to rectify.
The mould positioned in the pit is gently fired with cow dung cakes to melt and burn out the wax. Then whilst still hot the mould is firmly packed with sand and the metal poured from crucibles that can now hold up 60 kg of metal but which in antiquity are unlikely to have held more than about a kg. This means that for some of the larger Chola statues multiple crucibles pouring would have been necessary in quick succession from several furnaces operating together, in what must have been a highly organised and practised routine. Even so mishaps were and are inevitable, and as the Mānasāra instructs, small faults such as those on the arm of the Śiva Natarāja could be repaired, usually by cutting out the damaged area and mechanically hammering in afresh plate of metal.
Major faults such as those shown on the statue were beyond remedy and the casting abandoned. It is sometimes stated that ideally the casting should appear from the mould requiring no further treatment. Despite all the precautions with careful drying of the mould some cracking is inevitable and the flashes have to be filed flat. Then will begin the long process of scraping, followed by burnishing, performed to consolidate the surface, together with chasing to sharpen up details. These operations are then followed by a succession of careful polishing and washing operations (with tamarind water).
They now operate mainly in remote areas, but are very likely to have once been much more prevalent. In common with much of tribal culture, they have received relatively little attention from the art-historians and thus their origins and development are little known. Few ‘tribal’ castings have been identified from archaeological excavations, but they could have a very long history.
The tribal technology is quite distinctive not only from one group to another, even when living in close proximity to each other, but in many aspects significantly different from the more sophisticated and better-known casting traditions of the Himalayas and of South India. Three aspects of the tribal technology in particular are very distinctive and probably indigenous developments:
1. Tree resins used as a substitute for wax.
2. The model is often built up by winding wires or thin strips of resin or wax around the core instead of using sheets of wax.
3. The combined mould–cum-crucible method of casting.
The castings are almost universally of brass, incorporating mainly scrap metal. The modelling material is prepared from tree resins, notably dhuna, from the sal tree (Shorea robusta) which is boiled with mustard oil. This when warm is almost as malleable as beeswax, and on cooling is considerably harder and stronger. The warmed dhuna is pulled out into wires and tapes 30 to 40cm in length and 2 mm thickness, the tapes vary in width but are usually less than one cm wide. With this the Kainkuya Mal caste of itinerant smiths, at Bankura, West Bengal, for example, produce Hindu deities and rice-measuring bowls. Most of the figures are hollow castings, the core being of sandy clay tempered with vegetal matter. After the core has been shaped and dried the model is built up by winding the softened strip around it. As Reeves pointed out, in fact for these figures the only true modelling as such is in the core. The use of strips allows patterning, in particular on some figures the dhuna strips or wires criss-cross over the core leaving diamond-patterns of exposed core. When the completed model is invested the mould clay joins up with the exposed core and will hold it in place during the firing and casting operations. After the mould has been removed the core is left in place, partly to support the very thin casting (typically only two mm) but also to provide a contrast in colour and texture with the brass. Another technique is to construct an openwork figure completely of thin rods of resin to create a filigree effect.
As already noted, the mould-cum-crucible technique is used, and the provision of the pouring channel(s) is interesting, and again apparently unique to the tribal casters. Bamboo splits are inserted through the inner clay mould into the dhuna inside. More clay is now modelled around the inner mould and the splits to hold them in place and left to dry. Meanwhile the pouring channels formed of two rods of dhuna are inserted into the base of a small clay cup which will form the lower portion of the crucible and more moulding clay wrapped around them. When the clay around the bamboo splits has dried, they are pulled out leaving two channels into which the dhuna rods are inserted. Now the coarse outer mould clay, well-tempered with rice husk, is built up around the inner mould and pouring channels up to the level of the clay cup. Into this cup the broken-up pieces of metal are placed and the crucible completed with more clay, with just a thin sliver of straw running from the inside of the mould through the clay layers of the mould creating a small air gap. This is essential as the mould-cum-crucible is otherwise a completely sealed unit and would explode on heating. After drying the whole assemblage is baked in a horizontal position with the crucible innermost to receive the highest temperatures to ensure that the metal is fully molten. When it is judged that this has taken place the mould is removed, and after a short space of time, raised with the crucible uppermost allowing the metal to flow and consume the remains of the dhuna. Other tribal casters such as the Malyar at Ranchi, Bihar, fire the assemblage inverted with the crucible beneath and when the metal is molten the red-hot assemblage is carefully righted. Other tribal casters such as the Thetari Rana of Orissa and the Kaser of Jagdalur, Bastar, Madhya Pradesh, produce the dhuna wires or strips by extruding the warm resin through a wooden board pierced with holes, rather in the manner of noodles. It might be thought that this extensive use of wires and strips was in some way connected with the use of resin instead of wax, but this is not so, the Kaser, for example, use beeswax.
Bronze is an alloy consisting primarily of copper, with small quantities of other metals like zinc, nickel, and tin making it an excellent choice for casting intricately detailed sculptures. Sculptures made of Bronze lasts hundreds of years due to its high strength, and corrosion resistance properties. Bronze statues generally require minimal care and cleaning, and methods vary depending on the finish of the statue.
Vibrant fine polish finish: Copper in Bronze can react to hard chemicals and we do not recommend using any hard chemical based cleaning. The statue can be cleaned using mild soapy water with a soft clean cloth to remove any dirt, and dried using a clean dry cloth. After wiping clean, the statue must be dried well, and a thin layer of natural oil or coconut oil can be applied. Promptly wipe off any excess oil using a clean soft cloth, too much oil can attract dirt build-up increases and edges. Application of oil prevents the metal from direct contact with moisture in air and helps preserve the shine. We recommend cleaning fine-polished bronze statues once a month, you may need to clean them more or less frequently depending on the moisture in your environment.
Traditional cleaning methods uses lemon water mixed with tamarind paste, which is used to gently wipe the surface of the statue using a wash cloth, followed by rinsing the statue with plain water. Soap nuts boiled in water, and applying the resulting solution also helps to maintain the shine of bronze statues.
Brown patinas and antique finish: Statue that have an antique finish or patina finished already have a protective coating on them, and almost maintenance free compared to polished Bronze. Statues with antique or patina finishes can be cleaned using a wet soft cloth using mild soapy water to remove any dirt or stains, and coconut oil or any other natural oil can be applied after statue is dried. Any excess oil should be wiped off using a dry soft cloth. Cleaning these statues a few times a year would be sufficient, or as needed depending on the environment.
For artists and sculptors, bronze represents an excellent medium for producing sculpture. While marble can be difficult to work with, and easy to break and damage, bronze is a hard and ductile metal. Bronze is also preferable to other metals because, in the casting process, it is possible to achieve both detail and consistency. As molten bronze solidifies in a mould, it expands slightly, thereby allowing for every detail of the mould to be captured. Similarly, as it cools further, it will once again contract, therefore allowing for the easy removal of the mould. Depending on how the mould is made, this last property of bronze can mean that some moulds can be reused – so bronze sculptures, unlike stone ones, can easily be reproduced.
Lastly, bronze is esteemed by artists because of its rich colouring. Over time, bronze develops a distinctive patina, or burnish, which gives many bronze pieces the intensity for which they are so often lauded. And as well as being patinated, bronze sculpture can also easily be silvered (producing silvered bronze) and gilded (producing gilt bronze, or ormolu), giving it an extraordinary variety of uses, from furniture to clock-making to jewellery and much more.
The statue of the famous 'Dancing Girl, found to be in the times of Harappa. The statue, in bronze, is 10.5 centimetres (4.1 in) tall, and depicts a naked young woman or girl with stylized proportions standing in a confident, naturalistic pose. Dancing Girl is well-regarded as a work of art, and is a cultural artefact of the Indus Valley Civilisation. The statue is regarded as one of the oldest and magnificent artworks till date. It is utterly significant to decipher the origin of the First Civilization and the settlements in the Indian Subcontinent.
The famous Shiva Dance - Nataraja and the bronze sculpture, of the Natatraja of the Chola period is one of the most significant religious sculptures, and beholding the stature even today. Made with the Lost wax technique, the Chola bronzes bring together the art of metallurgy and the aesthetics of the sacred and the sensous dance come out in a remarkable fashion. Sculpting as an art has evolved to so much greater extent since the pre-historic times, and today a lot of variations can be seen in this, in terms of materials, aesthetic, and even themes. The sculptors are more profound these days and that can be seen in the installations today.
Bronze has, for millennia, represented an ideal medium for sculpture, favoured by artists because of its versatility, its rich colouring and its ability to achieve the finest of detail. Some of the first known sculptures were completed in bronze. Many artists – as we will see – are known more for their work in bronze than anything else. And unlike marble, bronze encompasses the whole range of what we might consider ‘sculpture’, from small figurines, to monumental statues, to modern abstract pieces.
Bhowmik, S.K. and Jani, M. Literary references on metals, metallic objects of art and metal technology. Archaeometallurgy in India, V. Tripathi ed. Sharada Publishing House, Delhi, 1998, pp.319-28
Davey, C.J. The early history of lost wax casting. Metallurgy and Civilisation, J. Mei and Th. Rehren eds. Archetype, London, (2009): 147-154
Hauptmann, A. Chemical Analysis of Prehistoric Metal Artefacts from the Indian Subcontinent, Appendix 1, Yule (1989): 261-67
Mukherjee, M. Metal Craftsmen of India, Anthropological Survey of India, Calcutta, 1978
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