Often it is advisable to heat the metal and put it “through the pickle” before working on it, especially in the case of tubing that has been lying by for some time and has become dirty.
For heavier work, a foot-bellows and gas blowpipe, or else a blowlamp, are essential. An “Ætna” paraffin blowlamp with horizontal burner will be found quite satisfactory, although, of course, if a gas supply is available in the workshop the user will find that a foot-bellows and blowpipe are more convenient. A blowlamp or blowpipe requires a suitable tray or “forge” of sheet-iron in which coke and odd pieces of brick or tile may be laid and used to pack round the object whilst the flame is being played on the part to be soldered.
Figs. 56 and 57.—Clip for Holding and
Applying Silver Solder
Fig. 58.—Pricker and Spatula for Consolidating Joints and Applying Solder
Among the smaller additional tools that will be required will be a clip to hold the solder ([Figs. 56] and [57]) and a brass pricker ([Fig. 58]).
Preparing the Borax Flux.
—Make up the flux on the slate by rubbing on it a piece of the lump borax moistened with water. This paste may be applied with the camel-hair brush to the parts to be jointed. The flux prevents the oxidisation of the surfaces, which would resist the amalgamation of the metals and the solder.