Dam
A reservoir or tank used for collecting or gathering a large quantity of metal to cast heavy castings. Whilst constructed in various ways, the main features consist in making it strong to maintain the metal, and of such materials as will conduce to its preservation in a good condition for casting with. A thoroughly well-dried loam and brick construction within suitable curbs is the best, taking care to have it as hot as possible when the metal enters, and keeping from 4 to 5 inches of dry charcoal on the surface. The mode of emptying the dam is usually by a shutter, which hermetically closes the outlet whilst it is being filled, and is raised by means of a controlling lever, so that the metal may be delivered at any desired speed. See GATHERING METAL; CURBS; SHUTTER.