Design Resource
Nachiarkoil Lamp - Madurai
Traditional Brass Lamp
by
Prof. Bibhudutta Baral and Srikanth Bellamkonda
Making Process
The process followed here is sand casting and is one of the cheapest casting processes.
In sand casting, a multi-part molding box is known as a casting flask, the top and bottom halves of which are known respectively as the cope and drag are used to receive the pattern. Molding boxes are made in segments that may be latched to each other and to end closures. Molding sand or foundry sand is a special type of sand used for casting. When moistened and compressed or oiled or heated, this sand tends to pack well and hold its shape. It is used in the process of sand casting for preparing the mold cavity.
A flat, clean, and even surface is chosen, and the master pattern is placed on it. The bottom portion of the molding box known as drag is placed in an inverted manner. A layer of dusting powder is thrown on the pattern to avoid the sand sticking on the object while removing it from the mold. Molding sand is filled and rammed, and the surface of the sand is stabilized with a sizing compound. Sand is filled in the container and hit using a rammer; this process is known as ramming. This makes the sand denser and hard to hold the pattern intact. Now the drag is turned upside down, the cope is placed on top of it, and dusting powder is applied over. Now again, sand is filled and rammed.
Now both the cope and drag are separated, and the master pattern is removed slowly with damaging the impression formed. Now the artisan makes a feeder hole in the cope to pour the molten metal into the mold and fill the cavity. Similarly, the drug runners are made for the metal to flow and fill the cavity. A runner is a path for the entrance of molten metal flow into the mold cavity. After making the runner, the drag is placed on the cope, locked, and now ready for casting. The metal for casting is collected from scrap metal. The scarp is cleaned, checked, and weighed. The required quantity of the scrap metal is taken and added to the crucible. The metal used in making the lamp is brass. Brass is a mixture of 40% zinc and 60% copper. The crucible is placed into the furnace and the metal and heated to its melting point of approximately 1200- 1300°C. Once the metal becomes molten, it is removed from the furnace, poured into the mold, and cooled.
After cooling is complete, the mold is broken, opened, and the casting is taken out. The lamp is made out of five different parts; all the parts are produced similarly by casting.
The casting obtained will have a rough surface and edges, and it has to undergo the finishing process. The sharp edges and surfaces formed during the casting are removed by grinding.
After grinding, it is sent for polishing work. Once the polishing is done, it's sent for design engraving. It is done by hand using various types of chisels. After engraving, the lamps are sent for final polishing. After this polish, the lamps will be glowing. The lamps are now packed and ready for sale.
Flow Chart:
