I have used a compound consisting of sulphur, 6 parts; white lead, 6 parts; and borax, 1 part. These substances are dissolved in concentrated sulphuric acid, and the surfaces to be united covered with the mastic, and pressed very hard together. In about six days the two pieces are so well joined that even hammering will not part them. J. M. Menegus.
Los Angeles, Cal.
A very good cement that I have used for cementing metal parts consists of the following ingredients: 2½ parts zinc oxide; 1 part zinc chloride; 5 parts pulverized limestone, slag, etc. Mix to a thick paste, using water. If the cement is wanted to set slowly, add 1 part of zinc sulphate instead of 1 part of zinc chloride. The adhesive power of this cement can be increased by adding 2 per cent of ferrous sulphate to the whole. Herbert S. Gladfelter.
Mix 10 parts of iron filings, 3 parts chloride of lime with enough water to make a paste. Apply this mixture to the joint, bolt firmly together and in twelve hours it will be set so that the iron will break sooner than the cement. David Melville.
A cement that will resist white heat may be made of pulverized fire clay, 4 parts; plumbago, 1 part; iron filings or borings free from oxide, 2 parts; peroxide of manganese, 1 part; borax, ½ part, and sea salt, ½ part. Mix these to a thick paste and use immediately. Heat up gradually when first using. W. R. Bowers.
The following iron cement, if properly prepared and applied, will unite broken iron parts very strongly, and may be found useful oftentimes for repairing broken machine parts of comparative unimportance. Mix equal parts of sulphur and white lead with about one-sixth part of borax and incorporate the three together thoroughly. When ready to use the mixture wet it with strong sulphuric acid and spread a thin layer of the cement on the joint to be united. Clamp together for five days when the joint should be dry and sound.
St. Joseph, Mich. J. W. Wilford.
A putty prepared with zinc dust does not have the drawbacks of those prepared with white lead or red lead. The oil used is that known as wood oil; this oil is extracted from a tree which grows in China and Cochin-China, known as the oil tree or Eloecocca Vernica. This putty possesses the peculiar property of hardening under the action of a very moderate heat, such as that which exists in steam boilers. With linseed oil, the hardening takes place at a higher temperature, but it is not as thorough, and a partial oxidation takes place, and it is accompanied by the production of carbonic-dioxid. With wood oil, the hardening is entire and rapid, and a rearrangement of molecules takes place without any chemical change; the physical constitution alone appears to be modified. The hardening of zinc dust cement is quite different from that prepared with white or red lead, as the action of oxygen is not required. Heating to 150 degrees centigrade is sufficient to complete the action, and at 110 degrees it is completed in six hours. This cement will keep for an indefinite period after hardening. Alfred Lang.
The following mastic may be used to unite metals of any kind. It becomes very hard. First, mix together well 4 parts of iron filings with 4 parts of chloride of ammonia. Then dissolve 100 parts of arabic gum and 20 parts of sugar in 100 parts of water, and add 1½ part of nitric acid. Boil this, and put the first mixture into it. When the mastic has to be used, mix one part of it with ten parts of new iron filings and some water, and heat it until a paste is formed, which is applied well heated to the pieces to be united.
Los Angeles, Cal. J. M. Menegus.
A cement that was commonly used on the Fallbrook R. R. locomotive front-ends some years ago to stop all cracks and leaks, was composed of litharge mixed with sufficient boiled linseed oil to make a stiff paste. Into this paste was thoroughly mixed about one-third bulk of old rope cut into short lengths - about one inch - and separated into its constituent fibers. This cement hardens like iron and the rope fibers hold it together while drying and also prevent squeezing out when the front-end casting is bolted to the smokebox. This cement will be found useful in many other places where it will be subjected to heat.
M. E. Canek.