A description of the making of wiped seams for lead-lined tanks will not be attempted as very few are made now. The plumber, however, is often called upon to make a seam joining two pieces of sheet lead. The beginner will do well to go over the following exercise carefully and practice it thoroughly.

Fig. 20.  Flat seam. Fig. 20. - Flat seam.

Materials

Two pieces of 8-pound sheet lead, 6 by 10 inches each; one bar of 1⁄2 and 1⁄2 solder; paste, paper, and rosin.

Tools

Rasp, shave hook, and soldering iron.

The 10-inch side of each piece is rasped and fitted together. The edges are cleaned and paper is pasted on leaving 1⁄4 inch for solder. Paste without the paper can be put on. This will make a joint 1⁄2 inch wide.

Apply the rosin to the joint, then with the heated iron and some solder tack the seam on the top, then on the bottom and middle. This will prevent the seam from spreading when the lead is heated. Solder and rosin can now be put on the full length of the joint. With a hot iron proceed to float the solder down the seam. The soldering iron must not rest at full length on the pieces of lead or it will melt the lead and render the work useless. The solder will flow and form a clean neat seam, if the iron is at the right heat and the right amount of solder is put on. If the iron is too hot, the solder will flow instantly when the iron is laid on it and the solder will disappear as it runs through the seam. If the iron is too cold the solder will not melt enough to flow. Too much solder on the seam will cause it to overflow, that is, the solder will spread beyond the papered edges. After a little practice this surplus solder can be drawn in on the seam with the iron and carried along the seam to some point that has not enough solder. When the seam is completed the edges should be perfectly straight and even. The iron is carried along the seam with one stroke which makes the seam appear smooth and bright.