3430. Copper and Aluminum for Journals

3430.      Copper and Aluminum for Journals. The most important alloy of aluminum is that composed of 90 per cent, of copper and 10 per cent, of aluminum. It possesses a pale gold color, a hardness surpassing that of bronze, is susceptible pi taking a fine polish, and is easier forged than soft iron. This alloy has found a ready market, and, if less costly, would replace red and yellow brass. Its hardness and tenacity render it peculiarly adapted for the journals and bearings of machinery. Christofle, of Paris, who uses it for a journal for a polishing disk, found that it lasted six times longer than ordinary journals - that is, 18 months. There were 2200 revolutions made per minute. It is further stated, on good authority, that a journal of this new bronze, which was employed for the axle of a sewing machine, making 240 revolutions per minute, did excellent service for 1 year without indicating the least deficiency. Journals of ordinary bronze do not, as is well known, last over 5 months. When more than 10 per cent, of aluminum enters into the composition of the bronze, the alloy gradually becomes weaker and less malleable, and at length so brittle that it is easily pounded in a mortar.

3431. Oroide, or Artificial Gold

3431.    Oroide, or Artificial Gold. This material is manufactured largely in the United States into imitation jewelry and other articles, scarcely distinguishable from gold, except by the inferior gravity; and it is a matter of surprise to almost any one to learn that it does not contain a single grain of the precious metal. It is made by taking 100 parts of pure copper, 17 of pure tin, 6 of magnesia, 9 of tartar of commerce, 3.6 of sal-ammoniac, and 1.6 of unslacked lime. The copper is first melted, and the other substances (excepting the tin) added, a little at a time, and the whole well stirred for 30 minutes, so as to produce a perfect mixture, when the tin is thrown in and stirred round until melted. The crucible is then covered, and the fusion kept up for 25 minutes, and the scum taken off, when the substance is ready for use. It is malleable and ductile, and can be worked in any form, even into leaves like gold. The alloy may also be made by substituting granulated zinc for tin, but it will not retain its brilliancy so long as when tin is employed.

3432. Talmi Gold

3432.    Talmi Gold. A beautiful gold-colored alloy, sold under the above name, gives, on analysis: copper, 86.4; zinc, 12.2; tin, 1.1; iron, 0.3. The presence of the iron was probably accidental.

3433. Yellow Dipping Metal

3433.    Yellow Dipping Metal. Melt together 2 parts brass, 1 part copper, with a little old brass, and 1/4 ounce tin to every pound of copper. This alloy is almost of the color, etc., of gold coin.

3434. Alloy of the Standard Measure used by Government

3434.    Alloy of the Standard Measure used by Government. This is composed of copper, 576 parts; tin, 59; yellow brass (22 copper to 1 of zinc), 48 parts.