PLUMBERY, the art of casting and working lead, and using it in buildings, &c. As this metal melts very readily, it is easy to cast it into figures of any kind, by running it into moulds of brass, clay, plaster, &c. But the chief articles in plumbery are sheets and pipes of lead ; and as these make the basis of the plumb er's work, we shall here give the process of making them. In casting sheet-lead, a table or mould is made use of, which consists of large pieces of wood well jointed, and bound with bars of iron at the ends, on the sides of which runs a frame, consisting of a ledge, or border of wood, two or three inches thick, and two or three inches high from the mould, call ed the sharps the ordinary width of the mould, within these sharps, is from three to four feet and its length is sixteen, se venteen, or eighteen feet. This should be something longer than the sheets are intended to he, in order that the end where the metal runs off from the mould may be cut ofl; 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, about an inch, or an inch and a half, in the length of sixteen or seventeen inches. 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 triangu lar 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, and on the opposite side is a handle to lift it up by, to pour out the melted lead ; and on that side of the pan next the mould are two iron hooks to take hold of the mould and prevent the pan from slipping, while 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 thirds of an inch ilia, with sand sifted and moistened, which is rendered perfectly level by moving over it a piece of wood called a strike, by trampling upon it with the feet, and smoothing it over with a smoothing plane, which is a thick plate of polished brass, about nine inches square, turned up on all the four edges, and with a handle fit ted on 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 big ness of the four sides, and having taken the dimensions of the or fore-part, make mouldings, by pressing long slips of wood, which contain the same mould ings, into the level sand, and form the figures of birds, beasts, &c. by pressing
in the same manner leaden figures upon it, and then taking them oft; 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 men tion the manner in which that is perform ed, it will be necessary to give a more particular description of the strike. The strike, then, is a piece of board about five inches broad, and something longer than the breadth of the mould on the in• side; 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 notch es. Before they begin to cast, the strike is made ready by tacking on two pieces of an old hat on the notches, or by slip ping 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 they tallow the under edge of the strike, and lay it across the mould. The lead being melted, it is ladled into the pan, in which, when there is a sufficient quan tity 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 is known by its beginning to stand with a shell or wall on the sand round the pan ; two men take the pan by the handle, or else one of them lifts it up by a bar and chain fixed to a beam in the ceiling, and pour it into the mould, while 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 prepar ed to receive it. The sheets being thus cast, nothing remains but to planish the edges, in order to render them smooth and straight ; but if it be a cistern, it is bent into !bur sides, so that the two ends may join the back, where they are soldered together, after which the bottom is sol dered up.