PLU

313

PLU

longer than the inside of

"out 5 • —--

, 0 ^ broad, and rather

that its ends, which are notched about two°j v n thg 6 ^’ ni!, "f r ' ( ^ e u pon the shafts ; this, being passed8 Ul 'p^°^ e bnigtli of the table, reduces the sand to a^'o h ea( j 1 p Ce * When this is done, the pan is brought to"on pfg .° tbe table, close to the copper, its sides havinge,) t i ta '° as ly guarded by a coat of moistened sand, to pre-^Ptied i n U "® ^ rom the heat of the metal, which is now0 *os, j(. vv >th ladles from the copper. These pans, or>1 to t], USt be observed, are made, as to their contents,'" e t at 0n 6 1 Uan tity of melted lead required to cast a wholea! to fet out t j me ’ anc * tbe ' n *" be bottom is so adjusted

"ill

during its progress along the table, just as much

i! 01 r "qu^a lete 'y cover i( >

o -oquif \-J- vuver ir, of the thickness and weight per

anq i -^'’ot'ything being thus prepared, the slit is^baita (•» le box ’ s moved along the table, dispersing itstj"* 8 a she° t ni tbe to P to tbe bottom, and leaving in its pro-s i" s heet ig 6 , ^ ea d of the desired thickness. When cool,are c l ° ^ U P ar 'd removed from the table, and otherslieetc St ’ all the metal in the copper is exhausted.Wti 80 for ' - - - H

ir"*

Of

'"els.

-- iuv mutai in iiio io gAiiau/n^u>

! ‘Oftned are rolled up, and weighed, it being by* e public is charged for sheet lead,places, instead of having a square box, upon

tial^Sh/bej 1 ' n tbe bottom, the pan consists of a kind

Un' 1 llll gles^ 1 "® com P ose d of* two planks nailed together at' v ell VVe en tl' n l en gtb, with two triangular pieces fittedt|, as 'hat' 6 ? 1 8t tbe ' 1 ’ en ds. The length of this pan, ason ni ° u 'd : if tlle box > is equal to the whole breadth ofdg ? bench- ^ stai, ds with its bottom, which is a sharp edge,by .^t it. at the head of the table, leaning with one sideu on the opposite side is a handle to lift it up0 nour out the liquid metal. On the side of■nn- "‘hi pr n j°uld, are two iron hooks to hold it to theist 0|,t of it .' ent it from slipping, while the metal is pour-rn 0 i 1 ' t ' (i!l <l ov e ' nt ° tbe mould. The mould, as well as the pan,it w ,; abou t two inches thick, with sand sifted and

br^ 1 " s trik e „*|"j, * s ren dered perfectly level by moving over

U P

!»bl e Pan ^xt* the° Urinn- ’ a ncl Ule

i UllH • . U J o

tu,.^ ’ a bom a U srno °tbing it down with a plane of polishedU P on ^ 1 ? 1 ai * ;er °f an inch thick, and nine inches square,, Ppftr, „„ a Ibe four edges, and with a handle fitted to

“16

’s Uiafi Concave side. Before they begin to cast, theto fa .°tcl leS) re! ’dy, by tacking two pieces of old hat on

'H ,Se y covering them with leather cases, so as

tlii c ^ ° r Uiore ? r S *^ e tbe stl ’ibe about the eighth of an"bib I '." Ss of ’j ove the sand, according to the proposed0f 'h e ' S ‘benJ 6 sbeet • the face, or under surface of the? ^oulfi ' . e ‘ n ’cd with tallow, and laid across the breadth"iea t 8 l ben . 1 * ts ends resting on the shafts. The meltedEntity j In *° tbe pan with ladles, and, when a suffi-° 1 ' Ui^ boar d to*i^ een P ut * n > tbe scum i® swept off with a

M,

U etl ' c oat 0 f l,J * le e< fge of the pan, and is suffered to settle

\ k l be rnet-q 8 '- 11 ^’ fo P revent its falling into the mould

r^iti* ' v ben' ft 13 P onre< f out. It generally happens, that

is ti 181 ta ken from the cointer, is too hot for

i t0 »tanfl tl,ereft *

P.tn i g {? n ^*ith

«t

the copper, is too hote suffered to cool in the pan, till ita shell or wall on the sand with which

tli

" a 6 'p

j aa n take 8 ■ W ° men then take the pan by the handle,! Ce 'lin by means of a bar and chain fixed to a

s 0a n " an r ,*i'®’’ anc '> turning it down, the metal runs intos : n as ' 10t| ier r„„„ . ... .

k

1,

tol<lC a11 ‘1.

e * ei rna n stands ready with the strike, andV V8 th e res -I i leta - ’ s P oure< f ' n , he sweeps it forward,tt thi s Ve the re f ' bue ’"to a trough at the bottom prepared|( ttode of USe ’ sbeet is then rolled up, as before.

m if ? inch °P er ation, the table inclines in its lengthtb e " et > or vv, an ’ ncb an< i a i |a *f> ’ n the length of 16i’Ct., j®beets ; t ? re ’ a ccording to the required thickness• ’ le thinner the sheet the greater the

4 L

declivity, and vice versd; the lower end of the mould isalso left open, to admit of the superfluous metal beingthrown off.

When it is intended to cast a cistern, the size of the foursides is measured out; and, the dimensions of the fronthaving been taken, long slips of wood, on which the mould-ings are carved, are pressed upon the sand, and leave theirimpression ; and figures of birds, beasts, &c. are likewisestamped in the internal area, by means of leaden moulds :whatever of the sand has been disturbed in doing this, is thenmade smooth, and the process of casting goes on as for plainsheets ; only, instead of rolling up the lead when cast, it isbent into four sides, so that the two ends may be joined atthe back, where they are soldered together ; and afterwardsthe bottom is soldered up.

The lead that lines the Chinese tea-boxes, is reduced toa degree of thinness, to which European plumbers cannot, itis said, approach. The following account of the process bywhich these plates are formed, was communicated to a writerin the Gentleman's Magazine , by an intelligent mate of anEast-Indiaman : The caster sits by a pot, containing themelted metal, and has two large stones, the lower one fixed,and the upper moveable, having their surfaces of contactground to each other, directly before him. He raises theupper stone by pressing his foot upon its side, and with aniron ladle pours into the opening a proper quantity of thefluid metal. He then lets fall the upper stone, and thusforms the lead into an extremely thin irregular plate, whichis afterwards cut into a proper shape.

Cast sheet lead, used for architectural purposes, is techni-cally divided into lead of 51b. 5^1b. 61b. 6^ lb. 71b. 7^lb. 81b.and 8^lb. by which is understood that every superficial footis to contain those respective weights, according to the priceagreed upon.

The milled lead used by plumbers is very thin, seldomcontaining more than 41b. to the foot. It is by no meansadapted to gutters or terraces, nor indeed to any part of abuilding that is much exposed either to great wear, or to theeffects of the sun’s rays : in the former case, it soon wearsaway; in the latter, it expands and cracks. It is laminatedin sheets of about the same size as those of cast lead, bymeans of a roller, or flatting-mill.

To cast pipes without soldering, a kind of mill, furnishedwith arms, or levers, to turn it by, is used. The moulds,which are of brass, consist of two pieces, which open andshut by hooks and hinges; their inward caliber, or diameter,being according to the size of the intended pipe, and usuallyabout two feet and a half in length. In the middle is a core,or round piece of brass, or iron, rather longer than the mould,and of the thickness of the proposed inward diameter of thepipe. This core passes through two copper rundles, one ateach end of the mould, which they serve to close ; and tothese is joined a small copper tube, about two inches long,of the intended thickness of the leaden pipe. These smalltubes retain the core in the centre of the cavity of the mould.The core being in the mould, with the rundles at its twoends, and the lead melted in the furnace, the metal is takenup in a ladle, and poured into the mould through a smallaperture, in the shape of a funnel, at one end. When tliemould is full, a hook is passed into the end of the core, which,by turning the mill, is drawn out; the mould is then opened,and the pipe itself is taken away. If it be desired to havethe pipe lengthened, one end of it is put in the lower part ofthe mould, with the extremity of the core passed into it; themould is then shut, and the upper rundle and tube appliedas before ; the pipe serving for rundle and tube at theother end. Fresh metal is then poured in, which unites