Lost-wax process : The secret of chola bronzes.

 

 

          Fig 1 : Chola bronze statue of Nataraja 

        The traditional workmanship of such Panchalokha (alloy of Zinc, Copper, Tin, Silver and Gold) image dates back to the traditions of Cholas. The ancestry of the workmanship has since been carried out by Sthapathis (craftsman, artisans or builders) who specialised in the craft. The Sthapathis of Swamimalai even today present beautiful idols with the age old method of  lost wax process of Idol making. Before building the Darasuram temple, the Sthapathis of Swamimalai ancestors worked on the Rajaraja peruvudaiyar temple. In the years that followed, their forefathers worked for the Swamimalai temple for Sivappa Nayak in the 16th century.

         Fig 2: The depiction of Hercules being casted

                         Source: The sculpture park 

          The fine alluvial soil (vandal man) from the river bed of kaveri’s quality was the reason for such beautiful images of their ancestors. The unique alluvial soil which is found 1 km away from swamimalai aroused the Sthapathis to settle down in the village. 40 families settled down for the rich resource that helped them make the icons. Post-independence the Govt. of India started a training Centre around 1951 to ensure the growth of the traditional lost wax process of metal crafting. By 1953 a Cooperative society for Sthapathis was created for enhancing their growth. This paved the way for people from different caste, places to learn the art. Today 600 plus Sthapathis live in swamimalai and 100 plus idol making centers are present in the village. In Tamil Nadu, idols can be found in three different styles: Pallava, Chola, and Pandaya. Out of which, chola idols are highly praised for their aesthetic sense and craftsmanship. This is mostly because of their precise dimensions. Chola statues capture human body proportions with utmost precisions following the agamic traditions. 

 Fig 3: Swamimalai Rajan Industry's idol casting.  

The chala murthys (movable Idols) are generally created in reference with the achala murthy (non-movable idols) i.e the ucchava murthy is made with reference from the Alaiya murthy /moolavar murthy.  The measurement system is based on the usage of Mula kol – primary measurement unit of thennai olai (coconut tree leaf/midrib). The olai is folded at several places proportionately according to digit calculations of Sthapathis for different body parts such as forehead, face, neck, chest, nabi (stomach), mekhala( nether region), thighs, knee ,legs and feet. This is then used as a reference to make the wax models.  Generally all statues are made for 9 tala. The male statues are made with 124 angulams and female with 120 angulams in height. One tala is equla to 8 angulam( a finger digit). The width of the male shoulder is about two pangu and female is just ½ while the rest of the body is the same. The statues bangamanam is also taken in account using the leaf as measurement. Banga is bend, the region of a bend occurs on a statue to denote its posture and movement. The dvi-banga, tri-banga etc are made on the wax model based on measurements. The wax model is made out of bee wax with resin and ground nut oil. This is completely carved while the wax is soft and then quenched in water to make it hard. The vandal man –loamy soil exclusive to the swamimalai village is then used to press on the existing wax model. Thin Iron rods are used to keep the mixture intact. Over this a layer of tough clay is used and molded into shape. A space as vent near the wax model is intentionally left. This clay model is sundried, a rope is used to tie around it. The ratio of weight of wax and alloy required to cast the product is in the ratio of 1:8 which means if the wax model weighs 1 kg then the casting will weigh around 8kg.The clay model is then heated, the wax melts away through the vent leaving a hollow inside the clay mold. Hence the infamous name lost wax process. 

        Post the melting of wax while the mold is still hot, the mold is buried underground just leaving the vent above ground. The metals are melted in a crucible. The molten metal then poured into the vent of the mold. The metal takes the place of the wax. After pouring metal the mold is left as it is for cooling. Minimum of 24 hours is given for the metal to cool down. Post this the clay mold is broken and removed. After which a rough metal statue is obtained. The surface is then scraped completely, filling is done. Post this emery paper is also used to smoothen it completely. The image’s features are sharpened and is polished in its final stages. Then the images are sent for sale.