This section is from the book "Soldering For Workshop, Farm And Home", by John Bonert. Also available from Amazon: Soldering For Workshop, Farm And Home - Information On Soft And Hard Soldering - Projects For The Workshop Explained And Illustrated.
There is now a copper ready with only one side tinned which affords a very good opportunity to demonstrate the importance of a well tinned copper. The soldering for this lesson can be done on a twisted copper wire joint. The importance of the lesson will be more to show how the solder transmits heat from the copper to the object being soldered than the actual soldering of the wire splice. It will be best to prepare several wire splices to be soldered. The wire will have to be scraped or sanded down to new metal before twisting. Fourteen Gauge wire or larger should be used. In making splices on wires or when wrapping wires around lugs such as is done in radio work always make the connections tight as solder is not a good conductor of electricity. Close contact should be made before the soldering is done.
The wire splice should be supported in some way so that both hands will be free to handle the copper and solder. Place the tinned side of the copper under the splice and bear up against it. Now touch a piece of rosin core solder to the copper right close to the splice and allow a little of it to melt. Be sure that the splice is partly submerged in this molten solder. Next touch the top of the splice with the solder and by this time enough heat will have gone into the wire so it will melt the solder. Do not pile solder on the splice but allow just enough so that the splice is neatly tinned. After removing the copper be sure there are no sharp points of solder projecting from the splice. If there are any just a touch with the copper will remove them. Now secure another splice to be soldered. With a piece of cloth wipe all excess solder off the copper and place the tinned side under the splice. There will not be enough solder on the point now to flood any of the splice. Instead of melting some solder on the copper as before just touch the top of the splice with the rosin core solder. It will be found that a very long time will be required before the splice will melt the solder and if the copper is not very hot it may not melt at all. But when solder is again melted on the copper the splice will melt solder very quickly. If one of the untinned sides is held to the splice there will be so little contact that the splice will not melt the solder. This demonstration should leave the beginner with a very good knowledge of why he tins his copper. The soldering of a wire wrapped around a lug is done the same way as the wire splice. Figure 10 shows the position of the copper when soldering a wire splice.
The beginner has now had nine lessons with the soldering copper and if he has followed the drawings and explanations carefully and has practiced faithfully he will be capable of doing a fair
Bend in shank to reach inaccess/b/e p/aces soldering job. There are times when the straight shank of the copper make it impossible to reach inaccessible places. The shank may be bent as shown in Figure 11 to reach such places.