Figure 6-5. - Tinning a copper (solder placed directly on copper).

Figure 6-6.-Forging a soldering copper.

powder form. Dissolve the powder in water according to the directions and dip the soldering copper into the solution and then apply the solder.

Forging Soldering Coppers. - Soldering coppers may be reshaped by forging when they become blunt or otherwise deformed. The procedure for forging a copper is as follows:

1. File the copper to remove all old tinning and to smooth the surfaces.

2. Heat the copper to a bright red.

3. Hold the copper on an anvil and forge it to the required shape by striking it with a hammer. (See fig. 6-6.) As you reshape the copper, a hollow will appear at the point. Keep this hollow to a minimum by striking the end of the copper. Do not shape too long a taper or sharp point, because this causes the copper to cool too rapidly. Turn the copper often to produce the necessary squared-off sides and reheat the copper as often as necessary during this part of the forging.

Figure 6-7.-Presto-lite heating unit.

4. Reheat the copper to a bright red, and use a flat-faced hammer to remove as many hollows as possible.

5. File and tin the copper using the previously described procedure.

ELECTRIC SOLDERING COPPERS. - Electric soldering coppers, or soldering irons, as they sometimes are called, are built with internal heating coils. The soldering heads are removable and interchangeable. Tinning is basically the same with the exception that the tip usually does not become cherry red. Forging or reshaping is not necessary, because the heads are easily replaced.

Electric soldering irons are usually used for electrical work or other small jobs. They are especially suited for this type of work, because they do not require auxiliary heating and they can be manufactured as small as a pencil.

GAS TORCHES. - Gas torches can be used in combination with soldering head attachments or as a direct heat source. The Presto-lite heating unit is ideal for soft soldering, because it delivers a small controllable flame. It also may be used effectively to heat soldering coppers. As figure 6-7 shows, this heating unit includes a fuel tank regulator, hose, and torch. It burns acetylene or MAPP gas as fuel in the presence of oxygen. The torch tip (stem) is interchangeable with other tips that come with the unit.