In the foregoing exercises, I have confined myself to the actual work of making the various joints. Now I will explain the practical use of them.
While the cup joint is not employed to any great extent in modern plumbing, yet it has its use in the installation of some fixtures. Lavatories, bath and toilets are sometimes connected with a short piece of lead on the supply. The tail pieces on the faucets can be soldered on the lead by means of a cup joint. A cup joint well made with a deep cup and the solder well fused is as strong as a wiped joint in a place of this kind. The evil of the cup joint is that some mechanics will only fuse the surface and leave the deep cup only filled with solder and not fused. This makes a tight joint, but extremely weak. On tin-lined pipe and block-tin pipe the cup joint is commonly used. When making a cup joint on block-tin pipe the soldering iron must not touch the pipe and fine solder should be used. When tin-lined pipe is being soldered, the tin lining must not be melted.
The overcast joint is not commonly used, but when there is considerable lead work to do the plumber finds it very handy in places where a wiped joint would take up too much room. We use it for an exercise for the reason that it teaches the beginner very rapidly the use and control of the soldering iron.
These seams are used in the construction of roof flashers, tanks (Sec. 33, Chapter XVIII (Plumbing Codes)) and lead safe wastes (Sec. 27, plumbing code). A hatchet iron is sometimes used on these seams.
The wiping cloths made of whalebone ticking make good, serviceable, and lasting cloths. Oil only should be used to break the cloth in. Moleskin cloths are very good, but they are very hard to get and cost considerably more. A plumber should always keep a good supply of ticking cloths on hand. The cloths are used only for wiping.
1⁄2-inch Round Joint. - This joint is the one most often required in actual practice. It serves to connect two pieces of lead pipe of the same or different diameters. It is also used to connect lead and other materials of which pipe is made. The workman, when he gets out on the job, finds that his work cannot be supported for wiping in such an easy and convenient position as illustrated in the exercises. It will be necessary to wipe the joint at almost every conceivable angle and position. The workman must employ his ingenuity to overcome any difficulties that may arise. Any draught of air should be avoided as it will make the solder cool quickly.
When it is found necessary to connect cast-iron and lead pipe, it is done by means of a brass ferrule wiped on the lead pipe. This joint is a very common joint and is found on sink, tray, and bath connections, as well as in many other connections that have lead and cast-iron pipes for wastes.
The 4-inch brass ferrule wiped on lead pipe is found under almost every closet. There is generally a piece of lead connecting the toilet with the soil pipe. Therefore, a brass ferrule is wiped on the lead and the ferrule connected with the soil pipe. This joint is also found on rain leader connections near the roof, connecting the gutter with the rain leader stack.
When a shut-off is required in a line of lead water pipe, these joints are used. Where it is necessary to joint lead and brass, this joint is required. The art of heat control over the lead and the brass is the essential point in these joints.
Branch Joints 5⁄8 and 1⁄2 Inches. - Where it is found necessary to take a branch from a water pipe, this joint is used at the connection. In practice, this joint may have to be wiped in positions that are rather difficult to reach, so the wiping of joints in the positions called for in the exercises is exceedingly good practice.
Branch Joints 1½ Inches. - These joints are very common and are found on waste and vent pipes. They are also found on urinal flush-pipe connections where the branch often is brass and the run lead.
When lead supplies are run directly to the bib on a sink, this joint is necessary. It becomes necessary to wipe in a piece of brass for a brass-pipe connection from a lead pipe, in which case this joint is called for.
The drum trap is used under sinks, baths, showers, and trays.