In actual practice, it has been found that a copper weighing one pound is best. After one gets more adept with the copper, it will be found advantageous to have several coppers of different weights. A half pound and also a four ounce copper will be found very convenient for extremely small work. But, do not begin to solder with a copper weighing less than one pound.
Soldering coppers are usually sold in pairs at the large tool dealers, and coppers listed at two pounds really weigh one pound each; when sending in a written order be sure that you specify that the copper is to weigh one pound singly.
A wooden handle especially made for soldering coppers should be purchased at the same time as the copper; these wooden handles are made large to protect the hand from the heat of the iron shank. The handle is usually furnished with a hole of the proper size drilled in it to permit the pointed end of the shank to be driven in the handle easily with a wooden mallet. If the hole is too small, it should be drilled out so that it is nearly as large as the diameter of the shank. The wooden handle must not be split when driven on with the mallet.
Fluxes.—Before tinning the point of the copper, some flux must be obtained, either a soldering paste or soldering fluid “killed acid.”
An excellent soldering paste called “Nokorode” is by far the best flux obtainable. It is inexpensive, a little goes a long way, and it will not rust or corrode the work as is the case with killed acid and some soldering pastes. It may be easily cleaned from the work after soldering and it makes soldering much easier and simpler for the beginner. Nokorode soldering paste may be obtained at any good electrical supply house or hardware store. If they do not stock it, they will get it for you. There is nothing else just as good on the market, but if for any reason you cannot obtain this particular brand, be sure that any soldering paste you buy is plainly labelled that it will not corrode the work.
Soldering fluid or killed acid is made of muriatic acid in which is dissolved all the pure zinc that it will hold in solution. This fluid is much used by tinners and is certainly an excellent soldering flux, but not nearly as good as the soldering paste for our purposes. However, it is very useful in the shop to dip the tinned point of the hot copper into it to remove the oxide or dirt formed after the copper has been in use for some time. The solder will stick to the point much better after the copper has been cleaned in this manner.
Directions for making the killed acid and the use of other soldering fluxes will be found on [page 68].
Tinning the Copper.—Having procured the soldering copper and handle, some flux and soft solder, and having fixed up some sort of heating apparatus, the next step toward soldering is to coat the point of the copper with solder: this is called tinning the copper.
Fix the copper firmly in a vise if one is at hand, as illustrated in [Fig. 17]. Then file each of the four faces of the point of the copper bright and clean with a flat file. It is better to use an old file for this purpose—one with rather coarse teeth. It will be observed that the copper is placed slantwise in the vise so as to bring one face of the square pyramid parallel with the vise jaws; this position permits filing in a natural horizontal position.
Each face of the point should be rounded slightly toward the point.