Cire Perdue : Its many forms and techniques
The Lost-wax casting known by various names such as “investment casting”, “precision casting”, or “cire perdue” in French is an age-old art form and is considered to be a living tradition all over the world. The Indian artisans and craftsmen have long been masters at extracting and shaping metals and alloys, as proven by archaeological finds from the 2nd – 3rd millennia B.C.
At present, the lost-wax process is widely practised in Himachal Pradesh, Odisha, Bihar, Madhya Pradesh and West Bengal. In each region, a slightly different technique is used. The technique is differentiated by method of casting applied , solid and hollow. In the northern regions of India hollow casting is practised whereas, in the south solid casting is done. However, the simple technique involved in both solid casting and hollow casting is the mechanical replacement of an object originally modelled in beeswax or a wax-like substance, with metal.
Indian knowledge of metallurgy predates technologies of many other civilizations, as shown by archaeological finds from the 2nd and 3nd millennium B.C.1
Lost-wax bronze casting is one of the oldest and one of the most popular art form in India. The dancing girl of Mohenjo Daro is the earliest known Indian lost wax process cast bronze figure (3rd millennium B.C.)2
“The intricate pattern and designs reproduced in casting the ‘dancing girl’ would, however, indicate that moist probably the lost-wax process was employed, as direct casting a mould would not produce a bronze of such a fine finish”3
The method of metal casting has been the cire-perdue (cire and perdue meaning wax and lost, respectively)4 or the lost wax process. The lost-wax process is attained by casting after a thorough modification. Lost- wax has been the name used for all types of casting. Lot-wax process is almost the same not only in India but also in the world over differences only can be seen in external details, in the way of modeling and the material used. Material using depends upon the availability and varies from zone to zone. In various parts of India, old casting process is still being practiced, without any major modifications.5
August Rodin, the famous sculptor, described the bronze icons of South India as “the most perfect representation of rhythmic movement in art.6
Rig Veda refers to lost wax casting technique as ‘maduchchista vidhana’. And Manushya Purana, another hoary text, refers to Viswa Karma’s five skills as those of, Manu (iron monger), Maya (wood worker), Twastha (vessel maker), Viswajhan (gold smith) and Shilpi (icon maker). A practitioner may call himself a Sthapathy if he is proficient in at least three of the five skills.7
Techniques involved in making solid and hollow casting in India
Today, the solid casting method is preponderantly practised in the southern region of India. The figure to be cast in metal is first carefully modelled in a wax preparation and after moulding , a wax drain hole-cum-pouring channel (sometimes called a runner) is prepared at the base of the image. Eventually, the mould is heated, the wax image is siphoned off through the drain hole and through the same orifice the molten metal is finally poured to replace the wax. The wax model s called the replica because afetr it is covered with a thin coating of clay , the inner wall of this preliminary mould will take the exact impression of the outer contours of the wax image. Three other layers of clay are plastered over the first coating and when dry , this composite mould is heated over a bellows-draughted ground furnace, causing both the wax runner and the wax replica to melt and drain off on the ground. In short, the wax is lost and it is from this craft sequence that the lost-wax (cire perdue) process of metal casting derives its name. The metal is separately heated in a crucible and when molten, is poured into the hollow drain hole, filling the void caused by the melting away of the replica. When cool, the mould is broken open, the pouring channel cut off and the casting blemishes chiselled away.
The hollow casting method is now largely practised in Central and Eastern India. A simplified and slightly smaller version of the envisaged metal form is first modelled in clay and, when dry, is wrapped with 1/16th of an inch thick hand-rolled or press ejected wax wires, as they are called, placed one against the other until the clay core is completely sheathed by them. This ribbed wax surface is often smoothened to a plain surface so that over it may be superimposed more wax wires to embellish and delineate the configuration. A runner or pouring channel is sometimes made by affixing a bamboo split to the replica after the first layer of the clay mould is pasted over the wax form. The split is then removed before its holding has had time to set. The second clay coating is fitted over the runner with a clay funnel containing a clay crucible for the scrap metal. This, when sealed with a clay cap, is placed, funnel side down , in aground furnace and heated until the metal melts. The mould is then removed and turned right side up in order to allow the heat-liquified metal first to displace the wax of the runner and then flow down to burn out and fill the 1/16th of an inch cubic space left between the clay core and the mould as a result of the loss of the replica. 8
References
1 Chintamani Kar, ‘Indian Metal Sculpture’, (London, 1952) p. l
2 Ajit Mookerjee, Indian Primitive Art, (Calcutta, 1959) p37
3 Ruth Reeves, Cire-perdue Casting in India, (New Delhi 1962) p.20
4 http://www.tms.org/pubs/joumals/JOM/0210/Pillai-0210.html
5 The Lost-Wax Casting of Icons, Utensils, Bells, and Other Items in South India http://www.tms.org/pubs/joumals/JOM/0210/Pillai-0210.html,R.M. Pillai, S.G.K. Pillai, and A.D. Damodaran
6 http://www.tms.org/pubs/joumals/JOM/0210/Pillai-0210.html
7 http://www.tms.org/pubs/joumals/JOM/0210/Pillai-0210.html
8 Ruth Reeves, Cire-perdue Casting in India, (New Delhi 1962) p.12