SOLDERING.
There are many ways of soldering, but the amateur will find the spirit lamp and the soldering iron the most convenient and expeditious.
In soldering tinned surfaces, no particular care is needed, as the solder will adhere easily, but in brass, or other metals, it does not do so without the aid of a rosin flux or acid solution. These simply act to make the surfaces chemically clean, so that the solder will hold. In fact, cleanliness is absolutely indispensable to success, for the solder will crawl off of any thing that is dirty or greasy, even though it may not appear to be so. Lead and tin are used for solder, and can be bought of any tinner very cheaply. The end of the soldering iron (which is not iron, but copper, by the way) should be tinned, otherwise the solder will not hold on it, neither will it follow when the iron is drawn along a seam.
The iron is readily tinned in this way. File it to the shape you want it, and put it in the fire, heating it pretty hot, but nothing like redness. You are then to wipe it clean quickly on a rag wet with soldering fluid, which can be had in drug stores, and is made of muriatic acid and sheet zinc dissolved in the same; the zinc must be clean, and in small strips, and shaken gradually until dissolved. The solution must then be well diluted with water. It is used by wetting the rag aforesaid with it and rubbing the iron in it; if block tin in strips be now rubbed on the end of the iron, it will adhere, and the iron will be ready for use. The iron must not be heated so as to melt off the tin and expose the copper underneath; for the iron is then useless until tinned again.
The soldering fluid is always to be used when brass, or any surfaces not coated with tin, are to be united.
By the spirit lamp you can join metallic surfaces very easily and quickly as follows: take your plate, or whatever it is you wish to join together, and scour it bright with fine sand-paper or pumice stone and water, on the faces to be united. Apply the soldering fluid, hold it over the spirit lamp blaze, and as soon as it is well heated, rub it over with a stick of tin; when it is well tinned, lay it on a hot flat iron or the stove for a minute, until you have tinned the other piece, then clap both together, and they will set instantly.
The blowpipe is very convenient for soldering small pieces together that cannot be touched with the iron, but as it requires some skill to use it, the amateur is not likely to be very successful with it. The articles to be soldered in this way, should be placed on a piece of charcoal, so that the heat will be equally distributed and kept up during the process.