SOLDERING. Under this title, in the Encyclopædia, we have given directions for soldering silver, brass, and iron; but there are other metals which must sometimes be soldered; and the following account of different folders, taken from the Philosophical Magazine, may be useful to many of our readers.
“When lead, tin, and bismuth, are mixed in a certain proportion, they produce a metal exceedingly fusible, which is known by the name of soft solder; but which, from its singular properties, may be applied with advantage to many other useful purposes. Newton, and after him Kraft and Muschenbrock, observed, that five parts of bismuth, three of tin, and two of lead, also five parts of bismuth, four of tin, and one part of lead, melted with a heat of 220 degrees of Fahrenheit; and they found that various mixtures of this kind were fusible by a heat not much greater than that of boiling water. At a later period, V. Rose, a German naturalist, discovered, that a mixture of four parts of bismuth, two of tin, and two of lead, as Kunkel recommended for soldering tin; and D’Arcet, among the French, that a mixture of eight parts of bismuth, three of tin, and five of lead; or eight of bismuth, four of tin, and four of lead; or eight of bismuth, two of tin, and six of lead; also sixteen of bismuth, seven of tin, and nine of lead—all melted, or at least became soft, in boiling water.
“According to the experiments made by Professor Gmelin, respecting the fusion of these three metals, a mixture, consisting of two parts of bismuth, one part of tin, and one of lead, which is the same as Rose proposed, gave a metal that was fused in boiling water. A mixture of six or more parts of bismuth, six of tin, and three of lead, or one part of bismuth, two parts of tin, and two of lead, gave, according to Klein, the folder used by the tin button-makers. The same workmen use also for soldering, according to Klein, a mixture of four parts of bismuth, three parts of tin, and five parts of lead. Among the many soft folders employed by the tin-men, a mixture of one part of bismuth, two parts of tin, and one part of lead, is, according to Klein, very much employed. Respecting this kind of folder, the experiments of Professor Gmelin give the following result: One part of bismuth, two parts of tin, and one part of lead, melt in boiling water. According to Klein, the tin-men employ for soldering a mixture of one part of bismuth, twenty four parts of tin, and four parts of lead. Eight parts of bismuth, three of tin, and five of lead, gave a metal exceedingly like tin in its colour and brightness, but very brittle; in water beginning to boil, it became not only soft, but was completely fused. This imitation, however, may be better accomplished by the mixture of Professor Lightenberg, which consists of five parts of bismuth, three
dering, three of tin, and two of lead. This metal is very like the former, though not so brittle; but it seemed to melt in hot water even before it came to boil."
As this subject has again come under our notice, it may be proper to lay before our readers what M. Van Braam says of the Chinese method of soldering frying-pans and other vessels of cast-iron, when cracked and full of holes. As the author admits that it must appear impossible to those who have not witnessed the process, such of our artists as have not been in China will give to the tale what credit they think it deserves.
"All the apparatus of the workman consists in a little box, 16 inches long and 6 wide, and 18 inches in depth, divided into two parts. The upper contains three drawers with the necessary ingredients; in the lower is a bellows, which when a fire is wanted is adapted to a furnace eight inches long and four inches wide. The crucibles for melting the small pieces of iron intended to serve as solder are a little larger than the bowl of a common tobacco pipe, and of the same earth of which they are made in Europe: thus the whole business of soldering is executed.
"The workman receives the melted matter out of the crucible upon a piece of toet paper, approaches it to one of the holes or cracks in the frying-pan, and applies it there, while his assistant smooths it over by scraping the surface, and afterwards rubs it with a bit of wet linen. The number of crucibles which have been deemed necessary are thus successively emptied, in order to stop up all the holes with the melted iron, which consolidates and incorporates itself with the broken utensil, and which becomes as good as new. The furnace which our author saw was calculated to contain eight crucibles at a time; and while the fusion was going on, was covered with a stone, by way of increasing the intensity of the heat."—M. Van Braam affects frequently to correct the mistakes of Sir George Staunton!