Very large engine cylinders, pans, and such vessels, are cast in loam-molds, which are built of brick, plastered with loam, then coated with coal-dust, and finally dried by means of a fire. This method is adopted with large plain objects, where a pattern would be expensive, and when few castings of one kind are required.
Iron molds, coated with blacklead or phnbago, have recently been introduced for casting pipes into; they are greatly more expensive than any other kind, but they enable the founder to dispense with a pattern, as, when once made into the required form, they are not destroyed like molds of sand or loam at each casting.
Bronze and brass are cast in molds prepared with finer sand than that used for iron. Pewter and similar soft metallic alloys are cast in brass molds. The type-founder, on the other hand, uses molds of steel, which are now worked to a great extent by a machine.
The variety of articles produced by F. or casting are very numerous, among others we may mention cylinders, cisterns, paper-engines, beams, boilers, pumps, and the heavy parts of machinery generally, gates, railings, lamps, grates, fenders, cooking vessels, and thelike, in iron: cannon, many portions of machinery, and numerous orna mental objects, in brass: sculpture and other works of art in bronze and the more costly instals. One of the most remarkable castings yet executed for the requirements of
modern engineering, was the cylinder of the hydraulic press used for raising the tubes of the Britannia bridge. It measured 9 ft. X 3 ft. 6 in., the metal being 10 in. thick, and weighed upwards of 20 tons. It remained red hot for three days, and it was seven days more before men could approach it to remove the sand. Sole plates for steam hammers, and for other purposes, have been cast more than double this weight, but the same care was .uot required in their execution. In regard to sculpture, perhaps the most wonderful casting known is the colossal statue of Bavaria at Munich, finished in 1850, which stands 54 ft. high, the face being equal to the height of a man. It took eight years to cast, and the cost of the bronze used was about R10,000.