Another feature on which successful calking depends lies in the quality of the lead used. Calking lead should be as soft as possible, and therefore free from zinc, solder, etc. For this purpose old lead pipe is often melted up, and may be easily made too hard by allowing the solder from old joints on the pipe to be melted with it. The calking of joints on vertical lines of pipe is straightforward work, but in the case of horizontal joints special means must be adopted to prevent the metal flowing out of the hub before it has an opportunity to cool.
Fig. 109. - Supporting of Vertical Lines of Pipe.
Fig. 110. - Soil Pipe Stack Ready for Water Test.
The old-style method consisted in winding a rope of putty, clay, or flax and putty around the pipe in such a way as to close up the opening between the hub and the pipe. A small opening was then made at the top to allow the metal to flow through. Now, however, special joint runners are generally used* for this purpose. They are made of asbestos rope and provided with a special clamp for holding the rope in position and for forming a gate for the metal.
In connection with the calking of lead joints a great variety of tools are used. The plumber is generally very particular concerning his calking tools, and in order that they may be exactly suited to his individual requirements he very often has them made special instead of using the tools ordinarily carried in stock.
The illustration and use of special calking tools is taken up in Chapter I (The Plumber'S Tools).
In Fig. 110 is shown a system of soil piping which constitutes the "roughing-in" of the plumbing system, and which has been made ready for testing. This system, with its cast-iron stack and galvanized wrought-iron vent work, is typical of the method of construction generally employed on such work, the use of wrought iron for vent work being now more universal than such work as shown in Fig. 89.