IMONO: Delicate Cast Iron
The Yamasho foundry had been creating 'chagama', cast iron tea pots, for 900 years, and is still Japan's largest producer of the traditional products.
The goal of the Y.M.D. Imono project was to find out, "how thin can they make it? And at that thickness, how big can they make it?" As the following conversation shows, the first Y.M.D. product, the big platter with the small holes, strikes the Japanese as not quite Japanese:
Hiroshi Funada, of the Yamasho foundry: "There's no concept of an iron 'morizara' (a serving basket, usually of bamboo). If it didn't have holes, it could be a basin. But with holes, well, it could be a 'morizara,' except it's too big for that--to Japanese eyes."
Takaji Takahashi, President of Yamasho: "To set down on a small table in a cramped Japanese home, it's just too big for a dish..."
Funada: "There is no tradition of iron plates."
Igarashi: "Products in heavy materials won't sell. But it seemed important to challenge ourselves to make something in cast iron that not only looked, but also was, light."
[Most of the platters average 3 kilograms, or 6.6 pounds.]
The physical restrictions in the art of cast iron have mainly to do with the interaction between the molten metal and the sand cast. Yamash's fame is in its capability to produce well-finished, thin products. (A steak platter, for instance, is ideally only three to three-and-a-half millimeters thick.) But difficulties are compounded when the piece is as big as the Y.M.D. platters, which range in diameter from 36.3 to 40 cm.
For starters, the cast must be of the right consistency; too viscous, and the vapor cannot escape before the molten iron, which is poured in at 1,500 degrees celcius, and the product is marred. On the other hand, a too-brittle cast will fall apart. In the attempt to create the most delicate piece possible, the speed with which the iron is poured is an important factor. If the molten iron rushes into the cast too quickly, the piece gains unwanted thickness. With 'nama-gata', in which the sand cast is still a little moist, if the piece is less than three millimeters, the molten iron is sluggish, won't flow properly, and cools before it has filled the cast. this gives the piece a substandard finish. In all these considerations, money is also at stake: shipping costs are affected by weight, and total waste determines individual production costs.
The object is to strike that perfect balance at which the product, even in the price range to which a handmade piece inevitably rises, is one which people will want to apprecieate forever