The aesthetic achievements of the Chola bronzesmiths are plain to see, yet the sophistication of their casting process is also impressive.
A thousand years ago, Chola craftsmen had reached a level of technical sophistication equalled only today using state of the art materials and techniques. As a result, the beauty of their Chola Bronzes remain undimmed by time, a remarkable achievement given that many museum pieces have been buried for hundreds of years (note 1).
Chola Bronzes were, and are to this day, created using the traditional lost wax, or cire perdu, process, a technique which has been used for thousands of years. The process begins by modelling a maquette, or full size model, of the figure in wax mixed with resin from the Oriental Plane tree and ground nut oil (four parts wax, four parts resin and one part oil). The wax figure is then coated with three consecutive layers of clay; the first coat is very fine and thin, about 3 mm, made from silt collected from the banks of the Kaveri River mixed with finely ground burnt coconut husks and cow dung, the second layer is field clay mixed with sand, and the third layer a mix of coarse sand and clay. After drying in the sun for a few days and wrapped in wire for reinforcement, the wax/clay is heated over hot coals until the wax figure melts, or lost, out of the mould. Molten copper alloy is then poured into the void and solidifies as it cools. Breaking the clay open reveals the rough casting, but destroys the mould, rendering each bronze icon entirely unique.
With all the resources of the empire at their disposal Chola bronzesmiths developed significant improvements to the lost wax process and their descendants kept this arcane knowledge a closely guarded secret for almost a thousand years. Recent laboratory analyses, however, has revealed the formula for their alloy (note 2). In addition to the usual copper and tin, the presence of iron, silver and gold ensured their formula conformed to the Shilpa Shastra’s accepted definition of panchaloha, literally ‘five’ ‘metal,’ the auspicious bronze alloy used to create sacred icons (note 3).
Anyone who has ever experienced a Chola Bronze knows the bronzesmiths who created them were master craftsmen, however, they were limited by their technology. Theirs is a very impressive achievement when they were using river mud, beeswax, charcoal and cow dung. Today we have the advantage of computer-controlled, electric furnaces and certified pure bronze alloys to ensure a technical quality Chola bronzesmiths could only dream of achieving.
There is an undeniable charm to knowing your sculpture was created the old traditional way, but we feel any sculpture associated with gods and goddesses ought to be of the highest possible aesthetic and technical quality. Even if they are never used in spiritual practice, Chola Bronzes are by definition, sacred sculpture and deserve an appropriate level of care in their creation.
Note 1 – After the collapse of the Chola Dynasty, south India was spared the degree of depredation Mughal invaders inflicted upon Hindu temples and art in north India. When the Mughals arrived in the former Chola homeland in 1311 their touch was relatively light and they stayed for only a hundred years rather than the thousand years in the north. The brevity of Mughal occupation ensured Vedic Hinduism in south India remained relatively untouched and its temples remain as they were built a millennia or more ago. Light touch or not, the Mughals were offended by these voluptuously sensual bronzes and many were melted down into cannon. Fortunately for us however, temple priests of the time secretly buried their icons underground or hid them deep in their vaults. From time to time a hoard is found but the pieces are considered unconsecrated and therefore spiritually without value. While a precious few are reconsecrated and returned to their temples, most are acquired by museums or private collectors through legal channel – or otherwise.
Note 2 – in 2015, a metallurgical analysis of 130 original Chola Bronzes revealed that secret recipe to be; 82% copper, 7.7% lead, 7.1% tin, 0.51% iron, 0.16 % silver and 0.01% gold, as well as traces of several other elements. Reference; “Tamil Chola Bronzes and Swamimalai Legacy: Metal Sources and Archaeotechnology” by Sharada Srinivasan, Ph.D. The Journal of The Minerals, Metals & Materials Society (TMS) August 2016, Volume 68, Issue 8, pp 2207–2221.
Note 3 – A bronze cast using panchaloha was considered auspicious because, in the words of the renowned Chola expert, Dr. R. Nagaswamy, “In the south five metals were used, with copper being the base. These five metals, called panchaloha, were symbolically associated with the five basic elements, earth, water, fire, air, and ether. According to tradition, all physical bodies, including humans’, are composed of these five elements in different proportions. The sacred metal image, being the body of the Divine on earth, is thus also made up of the five elements that are represented by the metals.” (Nagaswamy, Timeless Delight, p. 13).
It is no longer possible in the West for panchaloha to be used when reproducing Chola icons due to its Pb (lead) content. Environmental, as well as health and safety concerns for foundry workers, must take precedence. Caution; Pb (lead) remains a major element for casting reproductions overseas. If you currently have Indian-sourced sculptures in your home please ensure your wax coating covers the entire surface and reapply it annually.