There are many names for the process of lead joint-making, such as the flow-joint, the ribbon joint, the blown joint, the astragal joint, etc., to express the different positions and uses for which they are needed, but in the main they are made as follows:
1. The lead pipe to be joined is sawn square off with the proper toothed saw—attention being paid to making the end absolutely true, across the pipe.
2. One end of the pipe to be joined is first opened by driving in a wooden wedge, shaped like a plumb-bob, called the “turn pin.” Care should be exercised at this time not to split the end, 1⁄4 inch opening is usually enough, which leaves the pipe as shown at D, [Fig. 161]. Now, clean the internal part of the joint all around the part required for soldering—this cleaning can be done with the plumber’s shave hook or with a pocket knife. To complete this preparation “touch” the part with grease from a tallow candle.
3. Next is the preparation of the male part of the joint. This must be rasp-filed down to fit the enlarged opening. It is important to have a good fit throughout; hence, inside the enlarged opening must be also rasp-filed and the two surfaces to come nicely together before the solder is applied.
4. At this stage a paste called “plumber’s soil” must be applied outside 3 inches from the end of each piece of pipe; this is shown by the line E F in [Fig. 161], also at A B, [Fig. 160]; the line of the soiling should be very even and true in order to assure a workmanlike job and the soiling put on as before stated, 3 to 5 inches beyond the solder line on each side.
As the melting point of lead is 612 degrees or thereabouts, it is necessary to have solder melt at a lower temperature, and that made under the rule given will melt at 440 to 475 degrees.
No tool to a plumber is more important than the cloth used in joint making. To make it, take a piece of new mole skin or fustian, of moderate thickness, 12 inches long by 9 inches wide, fold it up one side 4 inches; then 4 inches again, and again 4 inches; then fold it in the middle, which will make your cloth 4 × 41⁄2 inches, and of 6 thickness. After this is done, sew up the ragged ends to keep it from opening. Then pour a little hot tallow on one side and the cloth is ready for use. In [Fig. 160-a] is shown, H, a hand holding the cloth C in the process of “wiping the joint,” which will now be described.
First place a small piece of paper under the joint to catch the surplus solder D and begin soldering as follows: Take the felt F in the right hand and with it hold the ladle three parts full of solder. To see that it is not too hot hold your hand within 2 inches or so of the solder; if it quickly burns your hand it is too hot; if you can only just hold your hand this distance, use it; but if you cannot feel the heat, the solder is too cold.
When you begin to pour your solder upon the joint do it very lightly and not too much at a time in one place, but keep the ladle moving backward and forward, pouring from E to J, first on one side of the joint to the other and from end to end.