in strips of a size to suit the size of the soil-pipe. They are very easily bent round on the pipe where they are to be fixed, and soldered to it with a copper-bit. The astragals are reversed, as shown at B and c, and the neck part of the upper astragal moulding is opened out a little, and rasped off on the inner edge, as shown in section, at A, to give space for a good body of fine solder for making a strong joint. The tacks are soldered to the pipe in the usual way, and to make them ornamental a device is cut out of the centre part, and dots are raised over the nail-heads, as shown at D. Roundheaded nails are fixed as shown at E, and that part of the tack which is to cover them is domed back by a tap or two from the small end of the mallet, as shown by the tack G, which is left unfolded for the purpose. The astragals round the pipe help to strengthen it, combining thus the useful with the ornamental. Bacon noticed in his day the neatness of astragal jointings, for he speaks of leaden pipes "bound with leaden bands."

Some plumbers prefer to cast the socket and astragals in a mould, and burning or soldering the socket-ends upon the lead pipe to save time and labour. Art. 13.)

(Chap. XXVI.,

CHAPTER XIX.

ELBOW JOINTS AND PIPE-BENDING.

1.

N my lectures to plumbers ten years ago, I expressed

should be obliged to resort to solder to an elbow joint— when circumstances compelled him to alter the course of a soil-pipe, ventilating-pipe, or rain-water-pipe. Judging

from their written papers and their practical tests, the student plumbers in connection with the City Guilds Technological Examinations are determined that no such reproach shall fall upon them, when they have arrived at the stature of men in the plumbing world; but the knowledge of pipe-bending has still to be learnt by many men here and there about the country, who, if not well advanced in the art of bending pipes, are well advanced in

age.

2. A man who would turn his back upon the plumber who made a copper-bit joint to the union of a lavatory plug-and-washer, and then go away and make an elbow mitre joint, as shown in fig. 61, would give a practical

Fig. 61.-ELBOW MITRE JOINT.

Fig. 62.-ELBOW JOINT. proof, not only of his want of knowledge of pipe-bending, but also of his want of comprehension in the fitness of things.

3. An elbow joint, however well made it may be, does not afford so good a passage for matters passing through a pipe as a bend, even though the later form of elbow joint, as shown in fig. 62, be adopted. Apart from any action the solder may have upon the lead, and the risk of solder running through at the mitreing during the soldering, there is the danger of fixing the underlap against the current, as shown at A, fig. 61. In fact this was a very frequent occurrence, as scores of old elbow joints have proved when

they have been cut out; and, as might be expected, such pipes showed most offensively where filth had collected in them.

4. As an elbow joint is inconsistent with good sanitary plumbing, and as it reflects a want of ability in the maker of it-elbowing the pipe because he cannot bend it—there is no necessity to describe how to make it.

5. It is about half-a-century ago that the more skilful plumbers began to bend soil-pipes, and gave up the bad practice of cutting and elbowing them with solder. And to-day so clever are the skilled in pipe-bending, that they can bend a lead pipe, of any size from in. to 6 in. diameter, into any shape that the most awkward of circumstances can call for. In my lectures I exhibited some specimens of 2 in. and 31⁄2 in. seamless lead pipe, bent into the shape of the well known S and half-S lead traps. Pieces of such strong lead pipe were also shown bent into the shape of capital letters, and when put side by side formed the word PLUMBING.

The following description of pipe-bending is largely taken from my "Lectures."

6. There is an art in bending lead pipes. Many try it, but miserably fail. In bending the pipe they considerably reduce the strength of the lead, especially at the heel of the bend, as shown by the illustration in fig. 63, at E and F. If the strength of a chain is only equal to its weakest link, the strength, and therefore the safety, of a stack of soil-pipe, or a stack of waste-pipe, is only equal to its weakest parts; so that when a 10 lb. or a 12 lb. lead waste-pipe, or an 8 lb. or a 7 lb. lead soil-pipe, is reduced at the bends to half its original strength, the whole length of the piping is depreciated accordingly.

7. There is not only the evil of weakening the pipe at the bend by men who are not skilled in pipe-bending, but there is also the further evil of contracting the bore of the

pipe, especially in the neck of the bend. The pipe at such parts is often contracted to quite half its original size, as shown at c and D. I often notice this as I travel about. Pipes of 4 in. diameter are reduced to 3 in. and less, and when this takes place in soil-pipes, waste-pipes, and ventilating-pipes, where the tubing should be quite of full bore at the bending, the value of such piping for its work is considerably reduced. If a stack of 4 in. pipe is reduced to 3 in. at its bends, the whole of the stack may as well have been 3 in., and the difference in the cost saved to the householder. I have seen, in bad workmanship, 5 in. piping re

Now no

duced to 4 in. at the bendings, 4 in. to 3 in., 3 in. to 2 in., 2 in. to 1 in., 1 in. to 1 in., 14 in. to 1 in. sanitarian, with a fair knowledge of plumbing, would allow such pipe-bending on any of his works. All these pipes, if they had been bent by men skilled in their trade, would have been of full bore throughout.

8. In making an elbow joint, as fig. 62, you have to cut out and get rid of a V-shaped piece of piping, but in making a bend you are in want of a V-shaped piece of piping, as shown at G and H, fig. 64. The skilful plumber will provide for this, and knowing that he is working a pliable material he will, in bending the pipe, dress the lead round

from the neck (c, fig. 63), where there is a surplus, to the heel (a, fig. 64), where there is a deficiency.

9. In making a bend in a 3 in. or 4 in. lead soil or ventilating-pipe (or any size from 3 in. and upwards), well heat the pipe by a flame from a gas-jet, or from wood shavings put inside the pipe, or by pouring some hot lead or solder upon the part to be bent. In the part which is to form the neck of the bend where you are going to kink the pipe in pulling it up, heat the lead up to the point when water dropped upon it would hiss, but do not heat it beyond

Fig. 64.-SHOWING WHERE LEAD IS WANTED IN BENDING (G, H).

that point, for though it would not melt, the lead would become brittle and break in the bending. When water dropped upon the pipe assumes a spheroidal form, it is a proof that the lead is too hot. Why water assumes such a form when dropped upon metals very hot, red-hot, is that the "sphere of water does not come into contact1 with the hot metal, but rests on an elastic surface or cushion of

1 Prof. Dewar, in his juvenile lectures at the Royal Institution this last winter, on "Fire and Frost," "threw some molten lead out of a ladle with a bare wet hand, the steam formed upon the hand by the heat of the lead preventing actual contact between the metal and the skin."