Fitting pipes might not seem like a difficult task; however, with different types and sizes of fittings and different methods of fitting pipes, pipe fitting can be complicated. Several different techniques may be employed in the fitting of a pipe; the technique used greatly depends on the pipe size.
Threaded and Push-Fit Pipes
"Slip fit" refers to a variety of pipe that need not be welded or twisted together. In order to fit these pipes together, two pipes of corresponding sizes---one "male" and the other "female"---are pressed together. The male pipe is the smaller one, which fits snugly into the female pipe. Slip-fit pipes can be cut to size easily with a saw and inserted into fittings once the burrs are removed with sandpaper.
Another common option involves "threading." Threaded pipes screw into one another. Similar to slip-fit pipes, male threaded pipes are threaded on the outside, while female pipes or fittings are threaded on the inside, allowing the male pipe to be slipped into the female pipe or fitting. Such options can provide a fairly long-lasting fit.
Pipe Welding and Cutting
For a permanent or semi-permanent fix, pipes are often secured to each other by welding. This can be accomplished in a number of ways. Pipes can be slip-fit together and then welded, or fittings may be welded around their circumference with a bit of solder. A less complicated option is called "solvent welding," wherein a tiny bit of solvent is placed around the pipe to be fit. Once the pipe is inserted snugly into a fitting, the solvent hardens quickly, creating a long-lasting seal. Compression fitting uses a rubber washer and a nut that is tightened after pipes are fit to make a seal.
Fitting Larger Pipes
Pipe sections in construction must be fitted together using specialised tools and equipment. Using excavating equipment to fit such pipes together is not recommended, as applying too much force may cause such pipes to break. Larger pipes are often fitted by placing a wooden block horizontally against the mouth of the pipe and wedging a bar against the block. When force is applied to the bar (which acts like a lever), the pipe is pressed securely into position. Even larger pipes---for instance, those 4 to 5 feet in diameter or larger---can be fitted with the help of mechanical pipe pullers.