Weights of Metals
The following table shows the weight of a cubic inch and cubic foot of different metals; also specific gravity: Metals. Weight of One Cubic Inch. Weight of One Cubic Foot. Specific Gravity. Pounds. Pounds. Cast iron ... .263 450 7.207 Wrought iron... .281 486 7.788 Steel... .283 490 7.833 Gold, cast... .696 1,210 19.258 Silver, cast... .378 654 10.474 Copper, cast... .317 540 8.788 Tin, block... .263 455 7.291 Zinc, cast... .248 437 6.861 Brass {copper 3 zinc 1}... .282 525 7.820 Lead, cast... .410 710 11.352 Aluminum... .092 160 2.560 Bronze {copper 10 aluminum 1}... .272 480 7.680 Bronze {copper 10 tin 1}... .309 535 8.560 Welding is the union produced between the surfaces of two malleable metals when they have been heated to fushion and rolled, pressed, or hammered. Few metals are susceptible to this process; but iron is the principal weldable metal. To prevent oxidation of the surfaces, when the pieces to be welded are taken from the fire they they are sometimes sprinkled with sand or some other substance, which fuses and spreads over the heated surface. Borax alone is employed for steel at times, but preference is given to certain compositions which are considered to favor a more intimate joining of the pieces. One composition for either iron or steel, or both together, is to calcine and pulverize together 100 parts iron or steel filings, 10 sal-ammoniac, 6 borax, 5 balsam of copaiba. One of the pieces is to be heated red, carefully cleaned of scale, the composition is to be spread upon it, and the other piece applied at a white heat and welded with the hammer. Another: Fuse borax with one sixteenth its weight of salammoniac; cool, pulverize, and mix with an equal weight of quicklime, when it is to be sprinkled on the red-hot iron and the latter placed in the fire. A German powder is: Iron-turnings 4, borax 3, borate of iron 2, water 1. See SOLDERING; BRAZING; BURNING. Wet-blacking is composed of water mixed with clay in varying proportions, along with one or more of the carbon-facings. See BLACK-WASH.