Metal Casting

Metal casting is a way to fabricate metal objects. When subjected to extreme heat, metal melts into a liquid. The molten metal is poured into a mold, where it cools and returns to a solid state, holding the shape of the space inside the mold. Once the object is removed, the mold can be reused to make an identical object.
§ Metal casting is a complex process. First the mold is created. The "lost wax" process is an effective way to create a mold which has been in use since the Bronze Age. In this process the artisan creates in wax a replica, or "positive" copy, of the object to be cast. Then the artisan covers the wax object in clay. When fired in a kiln, the clay hardens around the wax, creating a "negative" image of the object. This is the mold. (The original wax positive melts during the process; thus its title.) Molds are often created in two or more pieces so that the cast metal can be removed without destroying the mold.
§ Metal casting has some important advantages over earlier methods of working metals like blacksmithing. In blacksmithing, a smith heats and pounds metal until it achieves the required shape. This is a difficult process which requires a lot of skill. It's also quite time-consuming, as the smith can only work on one object at a time. Metal casting, on the other hand, is much more efficient. Once a skilled craftsman creates a mold, it can be used over and over again by less-skilled workers, with a large degree of certainty that the finished objects will be identical. Indeed, a mold can be created that will produce multiple copies of smaller objects, such as spearheads and daggers.