PLUMBERY, the art of casting and working lead, and using it in building.

As this metal soon melts, and with little heat, it is easy to cast it into figures of any kind, by running it into moulds of brass, clay, plaster, or other material. But the chief article in plumbery consists of sheets and pipes of lead; and as these form the basis of the plumber’s work, we shall here describe the process of making them.

In casting sheet-lead, a table or mould is made use of, consisting of large pieces of wood well jointed, add bound with bars of iron at the ends; on the sides of which runs a frame, consisting of a ledge or border of wood, three inches in thickness, and four inches in height from the mould, called the sharps. The ordinary width of the mould, within these sharps, is from four to five feet; and its length is sixteen, seventeen, or eighteen feet. This should be something longer than the sheets are intended to be, in order that the end where the metal runs off from the mould may be cut off, because it is commonly thin, or uneven, or ragged, at the end. It must stand very even or level in breadth, and something falling from the end in which the metal is poured in, viz. about an inch or an inch and a half in the length of sixteen or seventeen feet or more, according to the thickness of the sheets wanted; for the thinner the sheet, the more declivity the mould should have. At the upper end of the mould stands the pan, which is a concave triangular prism, composed of two planks nailed together at right angles, and two triangular pieces fitted in between them at the ends. The length of this pan is the whole breadth of the mould in which the sheets are cast. It stands with its bottom, which is a sharp edge, on a form at the end of the mould, leaning with one side against it; on the opposite side is a handle to lift it up by, in order to pour out the melted lead; and on that side of the pan which is next the mould are two iron hooks to take hold of the mould, and prevent the pan from slipping whilst the melted lead is pouring out of it into the mould. This pan is lined on the inside with moistened sand, to prevent it from being fired by the hot metal. The mould is also spread over, about two inches thick, with sand sifted and moistened, which is rendered perfectly level by moving over it a piece of wood called a strike, and smoothing it over with a smoothing plane, which is a plate of polished brass about one fourth of an inch thick, and nine inches square, turned up upon all the four edges, and with a handle fitted on to the upper or concave side. The sand being thus smoothed, it is fit for casting sheets of lead. But if they would cast a cistern, they measure out the bigness of the four sides, and having taken the dimensions of the front or fore part, make mouldings by pressing long slips of wood, which contain the same mouldings, into the level sand; and form the figures of birds, beasts, or anything else, by pressing in the same manner leaden figures upon it, and then taking them off, and at the same time smoothing the surface where any of the sand is raised up by making these impressions upon it. The rest of the operation is the same in casting either cisterns or plain sheets of lead. But before we proceed to mention the manner in which that is performed, it will be necessary to give a more particular description of the strike.

The strike, then, is a piece of board about five inches in breadth, and something longer than the breadth of the mould on the inside; and at each end is cut a notch about two inches deep, so that when it is used it rides upon the sharps with those notches. Before they begin to cast, the strike is made ready by tacking on two pieces of an old hat on the notches, or by slipping a case of leather over each end, in order to raise the under side about one eighth of an inch or something more above the sand, according as they would have the sheet to be in thickness; then the under edge of the strike is tallowed and laid across the mould. The lead being melted, it is put into the pan with ladles, in which, when there is a sufficient quantity for the present purpose, the scum of the metal is swept off with a piece of board to the edge of the pan, letting it settle on the sand, which is by this means prevented from falling into the mould at the pouring out of the metal. When the lead is cool enough, which must be regulated according to the thickness of the sheets wanted, and is known by its beginning to stand with a shell or wall upon the sand round the pan, two men take the pan by the handle, or else one of them lifts it by the bar and chain fixed to a beam in tlíe ceiling, and pour it into the mould, whilst another man stands ready with the strike, and as soon as they have done pouring in the metal, puts on the mould, sweeps the lead forward, and draws the overplus into a trough prepared to receive it. The sheets being thus cast, nothing remains but to roll them up or cut them into any measure wanted. But if it be a cistern, it is bent into four sides, so that the two ends may join the back, where they are soldered together; after which the bottom is soldered up.

We shall next describe the method of casting pipes without soldering. To make these pipes, they have a kind of little mill, with arms or levers to turn it withal. The moulds are of brass, consist of two pieces, which open and shut by means of hooks and hinges, their inward calibre or diameter being, according to the size of the pipe, usually two feet and a half. In the middle is placed a core or round piece of brass or iron, somewhat longer than the mould, and of the thickness of the inward diameter of the pipe. This core is passed through two copper rundies, one at each end of [7:18:63]the mould, which they serve to close; and to these is joined a little copper tube about two inches long, and of the thickness the leaden pipe is intended to be of. By means of these tubes the core is retained in the middle of the cavity of the mould. The core being in the mould, with the rundles at its two ends, and the lead melted in the furnace, the latter is taken up in a ladle, and poured into the mould by a little aperture at one end, made in the form of a funnel. When the mould is full, a hook is passed into the end of the core, and, by turning the mill, is drawn out; and after opening the mould, the pipe is also taken out. If they desire to have the pipe lengthened, they put one end of it in the lower end of the mould, and pass the end of the core into it; then shut the mould again, and apply its rundle and tube as before, the pipe just cast serving for a rundle, &c. at the other end. Things being thus replaced, they pour in fresh metal, and repeat the operation till they have got a pipe of the length required.

For making pipes of sheet-lead, the plumbers have wooden cylinders of the length and thickness required; and on these they form their pipes by wrapping the sheet around them, and soldering up the edges all along them.

The lead which lines the Chinese tea-boxes is reduced to a thinness which, we are informed, European plumbers cannot imitate. The following account of the process by which the plates are formed was communicated to a writer in the Gentleman’s Magazine, by an intelligent officer of an East Indiaman. The caster sits by a pot containing the melted metal; and has two large stones, the under one fixed, the upper moveable, directly before him. He raises the upper stone by pressing his foot upon the side of it, and with an iron ladle pours in the opening a proper quantity of the fluid metal. He then immediately lets fall the upper stone, and by that means forms the lead into a thin irregular plate, which is afterwards cut into a proper shape. The surfaces of the stones, where they touch each other, are exactly ground together.