Chapter VIII.THE WINDOWS AND LEAD-WORK.
We must now give to our dwelling-house those conveniences which call for the services of the glazier and the plumber. These two occupations are so often combined by the same tradesman, and the two classes of operations thereby resulting are both so necessary to the finishing of theexteriorof a house, that we may conveniently treat of them in one chapter.
Among the features which distinguish modern houses from those existing in the early ages of English history, few have been more conducive to comfort than the adoption ofGlass-Windows. Before the employment of that invaluable substance—glass—for this purpose, windows consisted either of uncovered holes in the wall of a house, whereby in order to admit light, the cold would also gain admittance; or else they were holes covered with oiled skin, oiled paper, thin horn, or some other partially transparent material, which would admit a dim light, and yet exclude wind and rain. It is only by placing ourselves in a room thus lighted, that we can form a correct idea of the increase of comfort resulting from the use of glass instead of such imperfectly transparent substances. The slow and imperfect modes of making glass soon after its introduction necessarily gave it a high value, and it could only be employed by the wealthy; but its price has gradually so much lessened, and its claim to a place among the necessaries of life so generally felt and acknowledged, that there are now but few persons in England, except those moving in the very humblest ranks of society, who have not a room with a glazed window.
The glass with which windows are generally glazed, is calledCrown glass. It is formed of different materials in different manufactories. In some instances the materials consist of fine white sand, carbonate of lime, carbonate of soda, and clippings or waste pieces of old glass; while in other cases they consist of white sand, pearl-ash, saltpetre, borax, and arsenic, in certain proportions. On this point we shall not dwell, for almost every manufacturer has a favourite receipt of his own. Whatever substances are employed, they are intimately mixed before being melted. The melting takes place in large crucibles or melting pots, made of a particular kind of clay capable of enduring intense heat.Several such crucibles are placed in a furnace, a little door being situate in the furnace opposite to each crucible. Through this door the materials are introduced and are suffered to melt; and as soon as these become melted, other portions of the materials are added, until the crucible contains a given amount of melted material. A curious effect is then observable. Although most or all of the materials are nearly opaque in their separate states, it is found that when they are all melted together, they form a transparent liquid, which isglass.
It requires about forty-eight hours of intense heat to bring the whole contents of the crucible to a liquid state. During this period, a quantity of dross or impurity, calledsandiverorglass gall, collects at the surface, and is carefully removed; it is afterwards sold to refiners of metals, who use it as a flux. The temperature of the furnace is then gradually lowered, by which means the glass loses sufficient heat to assume a pasty consistence, which is more convenient for the workman than if it were perfectly fluid.
The glass maker then stands before the door of the furnace, exposed to an intensity of heat such as few persons can adequately conceive, and dips into the pasty mass of glass the end of a hollow iron tube about five feet long. On withdrawing the tube, a portion of glass is found adhering to it, and this is made to equalize itself round the circumference of the tube by turning the latter rapidly round. The workman then applies his mouth to the other end, and blows through the tube, whereby the pasty mass is made to assume a hollow globular form at the remote end of the tube. This process is continued for some time and with great dexterity, until the globe has attained a considerable diameter and a proportionably small thickness. The globe is then somewhat flattened at the side opposite to the tube by pressing it upon a hard plane surface; and a solid iron rod, called apunt, having a small quantity of melted glass at the end, is applied to the centre of the flattened side opposite to the tube, to which it adheres; the tube is then removed by wetting the glass near the point of union with the tube, leaving a small circular hole. During these processes the glass is repeatedly heated by holding it for a few minutes at the door of the furnace, in order that it may retain the requisite degree of softness.
Thepunt, with the flattened globe of glass at its end, is then rapidly whirled round in a manner nearly resembling that in which a mop is twirled. By this motion, the globe becomes more and more flattened and extended in diameter, until at length, not being able longer to retain its shape, it bursts open, and spreads out in the form of a flat circularsheet of glass three or four feet in diameter. There is perhaps nothing in the whole range of the mechanical arts more astonishing to a spectator than this process, and there are few that require, from the workman, more of that dexterity of hand which can only be acquired by long practice. The workman continues to whirl the sheet of glass round,—gradually receding from the furnace,—until it is sufficiently set or solidified to retain its form. The punt is then, by a dextrous movement, detached from the centre of the sheet, leaving that bulb which is known as the “bull’s eye,” or the “knot.” The sheet is placed in an annealing oven, the temperature of which is lowered by slow degrees until cold; for it is found that glass is less brittle when it has been allowed to cool gradually than when the cooling has been rapid. Considerable care is required to regulate the temperature of the annealing oven; if the heat be too great the softened glass will bend: if the heat be insufficient the plates are liable to crack, or they prove so brittle that when they come to be used, the glazier will not be able to divide the glass so as to suit his purposes. Indeed, the management of the heat in the manufacture of crown glass requires so much care and skill that few workmen produce an article of the same value, even though working at the same furnace; hence crown glass is known in the market as firsts, seconds, thirds, and fourths; the fourth quality producing less than one-half of the price of the first.
We have not interrupted this description, to refer to engravings; but we may now illustrate it by the following cuts representing the glass in eight different stages of its formation.
1st. The melted glass attached to the tube, and worked on a board.
Working of melted glass on a tube
2nd. The workman blowing through the tube, to expand the glass.
Expanding the glass by blowing
3rd. Whirling it rapidly at the mouth of the furnace.
Whirling the glass at the furnace
4th. Transferring it from the hollow tube to the solid punt.
Transferring the glass to the solid punt
5th and 6th. Successive stages of expansion, by constant and rapid rotation.
expansion of glass by rotation
expansion of glass by rotation
7th. Final expansion into a flat circular sheet.
final expansion into a flat circular sheet
8th. The sheet of glass, held on a kind of fork, being placed into the annealing oven.
Sheet of glass on a fork going into annealing oven
When cold, the sheets of glass are cut into two unequal pieces, one of which contains theknot, and are packed with straw in woodencrates, in which they are forwarded to the warehouses, and from thence to the glaziers.
As plate glass is sometimes used for windows, a slight notice of it seems to be necessary in this place, in order that the reader may have a clear idea of the difference between these two descriptions of window glass.
The manufacture of plate glass is confined to very few hands, and great reluctance is manifested by the proprietors to permit visitors to inspect their works. The lateMr.Parkes, however, was permitted to visit the works of the British Plate Glass Company, at Ravenhead, and has recorded his observations in one of his valuable chemical essays, from which the following details are taken.
In the preparation of plate glass the materials are selected with greater care than in any other branch of the glass manufacture. The materials employed are sand of the finest and whitest kind, soda, and lime. Manganese and oxide of cobalt are also used for the purpose of destroying colour, which they do by the curious, and at first view, paradoxical property each has of imparting colour. The manganese has the effect of a slight tinge of red, the cobalt of blue; while the sand and alkali produce a slight yellow tinge; and thus these three colours (being those which naturally produce white light) by proper combination in the glass neutralise each other, and the result is an almost perfectly transparent material.
The process of filling the pots and fusing the materials is similar to that already described for crown glass. The cruciblesare of two kinds; the larger ones wherein the glass is melted, are calledpots, and because these when full of glass are too bulky and heavy to be moved, smaller ones, calledcuvettes, are employed. These are kept empty in the furnaces, exposed to the full degree of heat, so that when the glass is ready for casting and is transferred to them, they may not greatly lower its temperature.
The subsequent operations are very well described in an abstract ofMr.Parkes’s essay, given by the writer of the volume on Glass and Porcelain, in theCabinet Cyclopædia.
“When the glass is thoroughly refined, the cuvette—which must be perfectly clean, and, as already mentioned, of a temperature equal with that of the glass—is filled in the following manner:—A copper ladle, ten to twelve inches in diameter, fixed to an iron handle seven feet long, is plunged into the glass pot, and brought up filled with melted glass, which is transferred to the cuvette; the ladle during this transference is supported upon a strong iron rest, placed under its bottom, and held by two other workmen. This precaution is necessary to prevent the bending and giving way of the red-hot copper under the weight of fluid glass which it contains. When by successive ladlings the cuvette is filled, it is suffered to remain during some hours in the furnace, that the air bubbles formed by this disturbance may have time to rise and disperse; an effect which is ascertained to have ensued by the inspection of samples withdrawn from time to time for the purpose.
“Another essential part of the apparatus consists in flat tables whereon the plates of glass are cast. These tables have perfectly smooth and level metallic surfaces, of suitable dimensions and solidity, supported by masonry. AtSt.Gobain, and formerly also at Ravenhead, these tables were made of copper; the reason assigned for preferring this metal being, that it does not discolour the hot melted glass, while the use of iron was thought to be accompanied by this disadvantage. These copper tables were very costly, both from the nature of their material, and the labour bestowed in grinding and polishing their surfaces; and as the sudden access of heat that accompanied the pouring over them of such a torrent of melted glass occasioned the metal frequently to crack, the tables were by such an accident rendered useless. The British Plate Glass Company having experienced several disasters of this nature, its directors determined upon making trial of iron; and they accordingly procured a plate to be cast, fifteen feet long, nine feet wide, and six inches thick, which has fully answered the intended purpose—having, during several years of constant use, stood uninjuredthrough all the sudden, and violent alternations of temperature to which it has been exposed. This table is so massive, weighing nearly fourteen tons, that it became necessary to construct a carriage purposely for its conveyance from the iron foundry to the glasshouse. It is supported on castors, for the convenience of readily removing it towards the mouths of the different annealing ovens.
“The foundry at Ravenhead wherein this table is used is said to be the largest room under one roof that has ever yet been erected in this kingdom; it is 339 feet long, 155 feet wide, and proportionately lofty. Westminster Hall, to which the superiority in this respect is so commonly ascribed, is smaller—its length being 300 and its breadth only 100 feet. The melting furnaces, which are ranged down the centre, occupy about one-third of the whole area of this apartment. The annealing ovens are placed in two rows, one on each side of the foundry, and occupy the greatest proportion of the side walls. Each of these ovens is sixteen feet wide and forty feet deep. Their floors being level with the surface of the casting table, the plates of glass may be deposited in them immediately after they are cast, with little difficulty and without delay.
“When the melted glass in the cuvette is found to be in the exact state that experience has pointed out as being most favourable for its flowing readily and equably, this vessel is withdrawn from the furnace by means of a crane, and is placed upon a low carriage, in order to its removal to the casting table, which, as it is previously placed contiguous to the annealing oven that is to be filled, may therefore be at a considerable distance from the melting furnace. Measures are then taken for cleaning the exterior of the crucible, and for carefully removing with a broad copper sabre any scum that may have formed upon the surface of the glass, as the mixture of any of these foreign matters would infallibly spoil the beauty of the plate. These done, the cuvette is wound up to a sufficient height by a crane; and then, by means of another simple piece of mechanism, is swung over the upper end of the casting table; and being thrown into an inclined position, a torrent of melted glass is suddenly poured out on the surface of the table, which must previously have been heated, and wiped perfectly clean.
“The glass is prevented from running off the sides of the table by ribs of metal, one of which is placed along the whole length of each side, their depth being the exact measure which it is desired to give to the thickness of the glass. A similar rib, attached to a cross piece, is temporarily held, during the casting, at the lower end of the table. When thewhole contents of the crucible have been delivered, a large hollow copper cylinder, which has been made perfectly true and smooth in a turning lathe, and which extends entirely across the table, resting on the side ribs, is set in motion; and the glass, during its progress, is spread out into a sheet of uniform breadth and thickness. Its length depends upon the quantity of melted glass contained in the cuvette: should this be more than is needed for the formation of a plate having the full dimensions of the table, the metal rib is removed from its lower part, and the surplus glass is received in a vessel of water placed under the extreme end for the purpose.
“Mr.Parkes, in speaking of this operation, remarks—‘The spectacle of such a vast body of melted glass poured at once from an immense crucible, on a metallic table of great magnitude, is truly grand; and the variety of colours which the plate exhibits immediately after the roller has passed over it, renders this an operation far more splendid and interesting than can possibly be described.’
“At least twenty workmen are busily employed during this process of casting. From the time that the cuvette is removed from the furnace, to the completion of the casting by the hardening of the glass, the apartment must be kept as free as possible from disturbance; even the opening and shutting of a door might, by setting the air in motion, disturb the surface of the glass, and thus impair the value of the plate. So soon as it is completely set, the plate is carefully inspected; and should any flaws or bubbles appear upon any part of its surface, it is immediately divided by cutting through them.”
“When the plate of glass thus formed has been sufficiently fixed by cooling, it is slipped from the table gradually and carefully into one of the annealing ovens, where it remains in a horizontal position; its treatment differing in this respect from that pursued with crown and broad glass, which stand on edge during the annealing process. As each oven in this manner becomes filled, it is closed up by an iron door, the crevices of which are carefully stopped with mortar or clay, to prevent an access of external air to the oven; and thus to provide as far as possible for the gradual cooling of the plates, the necessity for which has already been sufficiently explained. When the glass has remained during about fifteen days in these ovens, they are opened, and the contents withdrawn.”
The plates have then to undergo the operations of squaring, grinding, and polishing, which need not be described in this place.
The various kinds of glass manufactured in Great Britain amount every year to the enormous quantity of 300,000 cwt., which is valued at two millions sterling.
Such, then, being a few details as to the mode of manufacturing glass; we will next suppose that the glass has reached the hands of the glazier or glass-cutter; and that the window-frame or sashes are ready to receive the panes of glass.
One of the earlier operations of the glazier is toprimethe sash, that is, to give it a coat of thin paint, for the purpose of making the putty adhere more firmly to the wood. He next takes the dimensions, in inches and eighths of an inch, of the groove or rebate in which each square of glass is to be fixed, and then proceeds to cut squares of those sizes from the semicircular pieces in his crate. This requires much tact and judgment, since to procure square or rectangular panes necessarily entails a loss of some of the circular portions. The circular sheets are made of diameters varying from forty-eight to sixty-four inches, and these are cut at various distances from the central knot, so that the glazier is enabled to choose that piece which experience teaches him will entail least waste: sometimes it is better to cut the pane from atable(the half which contains the knot), sometimes from aslab(the remaining portion of the disc).
In order to cut a table or slab, so as to procure a pane of the proper size, the straight edge of the table is placed near the glazier, and he cuts at right angles to it, by means of a diamond, and of an instrument called asquare; and two other cuts, at the proper distances, are sufficient to give a pane of the required size. With respect to the power by which a diamond is enabled to cut glass, we may explain it by saying, that it is a general rule among mineralogists, lapidaries, and others concerned with stony or crystalline bodies, that the hardest among a certain number of bodies willcut, or at leastscratch, any of the others:—in fact, tables of thehardnessof different substances are formed from the determination of what substances will mark or scratch others, that one being reckoned hardest which will scratch all others, without being equally affected by them in return. Now the diamond is the hardest body in nature, and cannot be cut by any substance but its own dust; but it can cut glass and other bodies, which are not so hard as itself.
The glass having been cut to the right size, it is next to be fitted into the sash; and among the many kinds of cement which might be suggested for this purpose,oil puttyis found to be the most advantageous, since it is conveniently soft when used, but hardens afterwards to the consistence of stone. Putty is made of whiting and linseed oil. The whiting is purchased in lumps, which are well dried, and then pounded and sifted. The linseed oil is poured into a tub, and the powdered whiting added to it, and stirred up with a stick. When some degree of stiffness is attained, the mass is taken out of the tub and placed upon a board, where more whiting is added, and the whole mixed up by hand. The mass is then beaten for a long time with a wooden mallet, until it attains a perfectly smooth and uniform consistency.
A portion of putty is taken up on a knife, and inserted in the groove of the window sash. The pane of glass is then laid in the groove, and gently pressed down in every part, so as to lie on the putty. As the sheets of glass are never perfectly flat, it is a rule among glaziers to let theconcaveside of a pane be within doors and the convex side without. After the glass is laid in, the edge is carefully coated with putty, to the extent of about an eighth of an inch: if this be carefully done, it is sufficient to secure the glass in its place, without presenting an unsightly appearance from the interior of a room. The opposite side of the glass now requires a little attention, since the bed of putty originally laid in the groove has been partially squeezed out by the pane of glass: a little trimming and finishing are all that are required in this matter.
When a broken pane is to be replaced in a window, it is done generally without taking out the sash; but in the case of glazing the sashes of a new house, such as we have been supposing, it is done before the sashes are fitted into their places. If sashes are glazed withplateinstead ofcrownglass, the only difference in the glazier’s method of proceeding is, that the pane being heavier, must be fixed in with greater attention to security. Sometimes a small beading or fillet of wood is used instead of putty, in which case it is either nailed or screwed to the sash.
Where skylights are used instead of windows, a different plan must be observed, since there are no cross bars to the sashes. In this case the squares of glass are fixed in somewhat in the way adopted in slating a roof, that is, the lower pieces are puttied in first, and the upper ones are lapped overthem, so that each pane projects about three-quarters of an inch over the one next below it. This is to effect two objects,—to prevent the necessity of puttying the joints, and to exclude rain.
Ground,fluted,painted,stained, andembossedglass, are occasionally employed for windows. These need not be noticed, since the processes by which they are fluted, stained, &c., would carry us to details of too extensive a nature. So far as the glazier is concerned, rather more care and delicacy are required in proportion as the kind of glass employed is more costly or more ornamental.
In some of the better kinds of houses, rooms are provided with double windows, separated a few inches from one another. The object of this is, to prevent the room from being affected by rigorous cold from without; for a mass of airwhen stationary, conducts heat very slowly; the stratum of air between the two windows, therefore,—being stationary,—is slow to conduct the cold from without, or, more correctly, to conduct the warmth from within.
Whether the glazier precedes the plumber or the plumber the glazier, or whether the labours of both alternate during the building of a house, is a question of no great importance to our present object. We will therefore proceed to notice the kind of material employed by the plumber.
The comparative cheapness of lead, its admirable qualities, and the facility with which it can be cast and rolled into thin sheets, and drawn into pipes, cause it to be extensively used in building. The most productive mines of this metal in our own country are situated in Derbyshire, Devonshire, Cornwall, in Wales, and in the North; in short, the ore from which lead is generally obtained, calledGalena, orSulphuret of Lead, is found in all countries where the primary rocks appear at the surface. The ore greatly resembles the pure metal in brilliancy; but it is brittle, and not so easily fused. It frequently contains a sufficient quantity of silver to make it worth while to adopt a peculiar process in the reduction of it, in order to separate this more valuable metal. The ore is first broken into small pieces, and is thenroastedin a reverberatory furnace, to drive off the sulphur. When this object is attained, the heat is increased, till the metal is fused, and then it is drawn off into moulds, which give it the form of blocks or slabs, calledsowsandpigs.
Sheet leadis made thus:—A large furnace is provided, into which pig-lead is thrown, and heat applied. Whenthe lead is melted, a valve or cock is opened in the side of the furnace, and the glistening liquid metal pours forth, and falls on a large table, covered over with an even surface of fine sand, and having a ledge of an equal height above the sand all round it. When the melted metal is poured on the sand, two men, holding each end of a stiff wooden rule, called astrike, draw it along the table, resting on each side ledge: the liquid lead is pushed onwards by the strike, till it covers the whole surface of an even thickness, which of course is governed by the depth of the ledge round the table.
Milled sheet leadis formed by rolling a cast plate of the metal between large iron rollers, turned by machinery. These rollers are set closer and closer together, till the lead is reduced by rolling to the requisite degree of thinness. By this process, the lead is rendered more dense and more equally so, than it ever is by simply casting: milled lead, consequently, is more durable than cast-lead.
It should be here noticed that lead, when it is used for roofing, or for lining cisterns and gutters, is always laid on an even boarded surface, and not on battens or laths, like slate and tiles.
Lead pipe is either formed by bending thin sheet lead round a cylindrical mould, and soldering the joint; or when the pipe is less than four or five inches in diameter, it is formed by casting a thick cylinder of lead with a small bore, and about five or six feet long. A long smooth iron rod, a little larger than the bore of the cylinder, is forced into this, and then the cylinder is gradually drawn through a succession of circular holes, decreasing in diameter, in a steel plate, by means of a powerful draw-mill, worked by a steam-engine. The lead is by this process extended out over the iron rod, which preserves the bore of the pipe of an equal diameter, and when the pipe is sufficiently reduced in thickness, the rod, ortriblet, is forcibly drawn out, and the pipe left with a smooth bore, ready for use. Attempts have been made to form lead pipes wholly by casting; an outer mould and an inner core being so adjusted as to leave a space between them, into which lead might be forced while in a melted state; but this method has not been practically worked out to any great extent.
When a roof is to be covered, or a cistern lined, with lead, the sheet of the metal is unrolled on a level floor, and madefree from creases and undulations, by beating them down with a heavy woodenflogger, formed like a roller with a flattened side, and a handle to it. The plumber then draws on the lead the form into which it must be cut to fit the surface it is intended to cover, and afterwards cuts through the lines described with a strong sharp knife. The piece is then rolled up again for facility of carriage, and raised by tackle into its intended situation, it being placed there so that when again unrolled, it may lie in the proper situation and position on the boarding. The sheet is then again beat out flat as before.
The next sheet being put into its place, and so that the edges of the two may overlap about one and a half or two inches, the workman proceeds to make the joint, or to solder the two sheets together. The first step for this purpose is to scrape the two edges or borders of the sheets that are to come in contact quite clean and bright, with a tool constructed for this purpose, consisting of a small triangular bit of steel ground sharp at its edges, and fastened at right angles on an iron socket, fixed in a handle. When these borders of the lead are quite clean, they are painted over with black-lead paint, to prevent their tarnishing, oroxidisingagain, as the solder will only adhere to a clean pure metallic surface. The paint also serves as a flux to cause the solder and lead to melt together, and thus make a close joint.
The solder is melted in an iron ladle, on a rude temporary fire-place, built as near the spot where the solder is wanted as possible. The plumber having turned back the edge of the upper sheet at the joint, an assistant carefully pours the solder on the lower edge. The workman then spreads it evenly along the joint, by means ofsoldering irons, which are irregularly-shaped iron bars, swelling at their ends into rounded forms of different sizes and shapes, according to the particular purpose for which they are intended. These irons are used in a red-hot state in order to keep the solder melted.
As soon as the workman has spread the solder, he presses and hammers down the upper edge upon the lower, and spreads the solder forced out of the joint, along the seam. The outermost edge of the lead covering is nailed down to the boarding or cistern-frame by nails, with their heads leaded over to prevent the corrosion of the metal, by the chemical orvoltaicaction that takes place when two metals in contact are exposed to moisture. The situation of the soldered joints depends on the size and form of the surface to be covered over; and a good workman considers well how he can cut out the lead so as to have the fewest joints, and these inthe most favourable situations. If he has to line a cistern, he will cover the bottom in one piece, cutting the lead large enough to admit of its turning up for an inch or two at two of the sides, the joint consequently being made at these angles.
When a large roof, like that of a church, is covered with lead, this is laid on in parallel bands as wide as the sheet will admit of, the edge of one sheet being turned over a wooden roller or fillet, nailed down on the boarding to receive it, while the edge of the next sheet is turned over the former lead again; the double thickness being wellfloggeddown to render the joint water-tight: and in this case no solder is used.
The edges of lead gutters that turn up against the inside of the parapet are either laid as flat against the brick-work as possible, and secured so by ironholdfasts, so as to prevent rain from getting in; or to effect the same object, they are in all the better kind of buildings, turned into a joint, in the brick-work, between two courses.
When the plumber has to join two lengths of lead pipe into one, he opens out the end of one length into a funnel-shaped aperture, by gently driving a wooden cone into it, so as to avoid splitting the pipe. The end of the other length is then scraped down a little by the triangular tool before mentioned, not only to obtain a clean surface for soldering, but to allow of the end fitting into the funnel-shaped aperture alluded to. The two pipes being thus put together, the workman holds a thick wadding of old woollen cloth, well greased, under the joint, while a labourer gently pours melted solder over the joint, which the plumber smoothes and shapes down by his soldering-iron and the cloth into a regular smooth rounded swelling, all round the joint, making this perfectly close and water-tight.
We observed in the chapter on “Roofs,” that within the last few years, the metal zinc has been much used instead of lead for all the purposes of the latter, and many others beside, for which the admirable qualities of zinc particularly qualify it. This metal is lighter than lead, and equally durable in the open air. It bears water almost equally well; but it is not so flexible or manageable, being neither so fusible nor malleable. Zinc only admits of being rolled or hammered when it is heated to about two hundred and twenty degrees of Fahrenheit. When cold it is too brittle to bear much bending; nevertheless, pipes, gutters, cisterns, chimney-pots, &c., are made out of sheet zinc; and roofs, &c. covered with it.
The solder alluded to above, as being the means of joining two pieces of sheet lead or of lead pipe, is an alloy of lead and tin, in the proportion of two parts of the former to one of the latter. This mixed metal is fusible at a lower temperature than either the tin or the lead separately; and may therefore be applied in a melting state to tin or lead, which still remains solid, even at the same temperature: this it is which constitutes the principle of soldering. The solder is cast into triangular bars, weighing from thirty to fifty pounds each.
There has, however, been a method recently introduced which seems likely to effect considerable changes in the mode of joining pieces of metal, whether for buildings or for other purposes; and we may here give some account of it.
The great object of soldering is of course to form joints or seams in pipes, and other articles, so perfectly, that they shall be subject to no leakage or flaw. But this object is not easily obtained by the old method of soldering; the chances of flaw are numerous, and have been enumerated thus:—1st, the difference of expansion between the lead and its alloys with tin, a difference which is particularly experienced in very cold or very elevated temperatures; 2nd, the electro-chemical actions which are developed under certain circumstances by the contact of two different metallic substances;[5]3rd, the very powerful reaction which a number of chemical agents exert on alloys of lead and tin, though not upon lead alone; 4th, the extreme fragility of these alloys, which, particularly when heated, often break on the slightest blow; 5th, the difficulty of making the solder adhere to the surface of the lead;[6]6th, the use of rosin, which frequently conceals fractures for a time.
All of these objections are removed by a new method of soldering, invented by M. E. Desbassays de Richemont, who has recently obtained, at the National Exhibition of Arts at Paris, a gold medal for his invention. The committee on whose recommendation the medal was awarded, included some of the most distinguished chemists and men of sciencein France; and in their report on the subject, they say:—“We consider this invention of the highest importance; it is applicable to many branches of industry, and will render great service to a large number of manufactures. Its efficacy has not only been proved by experiment, but is confirmed by the fact, that most of our eminent manufacturers and tradesmen have taken out licences for the use of it.”
This invention (which is patented in France, Great Britain, and Ireland) is calledautogenous soldering, and consists of a method of uniting two pieces of metal without the use of solder. The parts to be joined are united by the fusion of the metal at the points or lines of junction; so that the pieces when joined form one homogeneous mass, no part of which can be distinguished from the rest. This result is obtained by means of jets of flame, produced by the combustion of hydrogen gas, mixed with atmospheric air; these jets are so ingeniously managed, that they can be used and directed with as much, or even more facility, than the common tools of the solderer.
The apparatus employed in this new process consists of a peculiarly constructed vessel for producing hydrogen gas, to which vessel a variety of tubes and jets can be attached, so as to meet the various demands of the solderer.
A section of the gas-producer is shown infig.1:ais a leaden tank, for containing dilute sulphuric acid;b, a pipe which passes from the acid vessel to another similar leaden vessel,c, which is to contain cuttings of zinc;dis a conical plug, with a stalk and handle covered with lead, by the opening of which the acid is allowed to flow through the pipeb, to the zinc cuttings, and thus hydrogen gas is produced;eis an opening by which zinc is put into the vesselc. The opening,e, has a cover furnished with screws and nuts, by which it may be firmly secured;fis an opening by which acid and water are poured into the vessela. When the hydrogen gas is produced, it has to pass through the safety chamberg;his a bent tube or pipe, which conducts the gas from the vesselcto the bottom of the safety chamber, the mouth of the pipe dipping into an inch or two of water in the safety chamber. This water is introduced by the pipei, which is furnished with a stopple. The cock,k, cuts off the flow of gas from the vesselc, to the safety chamber,g. A flexible tube,m, is screwed to the top of the safety chamber, and conveys the gas to the working instrument, or jet, in the hands of the solderer.
As long as the dilute acid is allowed to flow upon the zinc, hydrogen gas will be produced: the gas will also be formed as long as the cock is open, which allows the gas to issue asit is produced; but as soon as the cock is shut, a small quantity of gas accumulates, and interferes with the further action of the liquid on the zinc. Consequently there is no danger of an explosion, because the production of the gas is never more than is required for working; and when the work ceases, the production of the gas ceases also. When the dilute acid has become saturated with oxide of zinc, and gas ceases to be produced, the discharging pipe is opened, and the liquid withdrawn. By spontaneous evaporation, this liquid furnishes sulphate of zinc (white vitriol), which may be sold at a price which will more than cover the first and daily cost of the apparatus.
Section of gas producer
Fig.1.
Section of gas apparatus where workman operates
Fig.2.
We now proceed to describe the part of the apparatus with which the workman operates. Infig.2, the flexible tube,m, is attached to one arm of the forked tube,o; the other arm ofois attached to a pipe,q, proceeding from a bellows, or other means for supplying air. The solderer may work a bellows with his foot to supply his apparatus with air, or the men in a whole factory may be supplied from a blowing apparatus. A cock,n, regulates the supply of gas;pis a cock for regulating the supply of air;ris the pipe or tube in which the gas and air are mixed;s, the beak or tool, from which issues the jet of flame,t, with which the workman operates.
The forked tube,o, is attached to the girdle of the workman, and the regulating cocks,nandp, are so placed, that by using one hand, the man can allow the exact proportions of air and gas to issue. By stopping both cocks, the flame is of course extinguished.
The beak,s, may be exchanged for others of every variety of form, so as to produce jets of flame adapted to any kind of work.Fig.3 is a tool formed like the rosette of a watering-pot, capable of producing a most intense flame of jets.
Tool to produce intense flame of jets
Fig.3.
Allows a length of flame instead of a point to be produced
Fig.4.
Fig.4 allows a length of flame instead of a point to be produced;nis the hydrogen gas-pipe and cock;p, the air-pipe and cock;r, the tube, in which air and gas mingle;u, a pipe with a longitudinal slit on one side of it; andv, another pipe coveringu, and exactly fitting over it. Gas and air escaping from the slit, on being ignited, will produce a long strip of flame, which may be lengthened or shortened by sliding off or on the covering tube,v, on the slit tubeu.
Soldering tool
Fig.5.
Fig.5 is a soldering tool, to be used where a jet of flame is not available, as in joining zinc. In this arrangement, the hydrogen and air flame heats apiece of copper,y, with which the work is performed.wis the tool, with a hollow handle and stalk; air being supplied by the pipep, passes through the hollow handle and stalk;xis a small tube which passes down the hollow handle and stalk,w, and conveys gas from the pipento the extremity ofw, where it mingles with the issuing air, and, on being ignited, the flame will heat the piece of copper,y, (which, of course, may be of the shape of any soldering tool required,) held by the arms,z.
One great advantage to the public at large to be derived from the general introduction of “autogenous soldering,” will be the diminution of the number of cases of the escape of water and gas, which every day occasion so much inconvenience and even danger as regards the stability of buildings, the maintenance of the public thoroughfares, and the security of life.
The disuse of charcoal and tin by plumbers will have the important effect of rendering their trade less unhealthy, the fumes from their brasiers, and the arsenical vapours emanating from impure tin, being a very common cause of serious maladies.
By the old method of soldering, there is great danger of setting fire to houses and public buildings: the destruction of the corn market of Paris, and of the Cathedrals of Chartres and of Bruges, by fire, was partly owing to the negligence of plumbers; a negligence for which there could be no reason, if the new method of soldering had been introduced, since it is only necessary to turn a cock in order to extinguish or rekindle, at any moment, the jet of gas which serves for the plumber’s tool. By means of the new apparatus, a soldering flame can be conducted to a distance of several fathoms without the dangerous necessity of lighting a brasier to heat irons, to melt masses of solder, and to carry the whole into the midst of complicated carpentry work.
The disuse of solder will also greatly reduce the price of plumber’s work, without, however, diminishing the demand for the services of the workmen. The disuse of seams or overlapping, which from this new mode of connecting lengths of lead will almost entirely be given up, will alone occasion a considerable saving in the quantity of lead employed. The ease with which lead of from one-thirtieth to one-tenth of an inch in thickness may be soldered, and defects repaired, will permit of the substitution of this, in many cases, for thicker lead, and thus diminish the expense; perhaps, also, it will give rise to the use of lead for purposes to which it has not yet been applied, or the return to others, in which from motives of economy it has been superseded by other metals.
The plumber will also be indebted to M. de Richemont’s method for several important improvements. He will be able in future to make internal joints wherever a jet of flame can be introduced and directed; to reconstruct on the spot, of pure lead, any portion of a pipe, a vase, or a statue, that mayhave been removed or destroyed; to execute in rapid succession any number of solderings; to repair in a few minutes all dents, cracks, and flaws, in sheets or pipes of new lead; to remove entirely the enormous edges or knots left by the old-fashioned joints, and that without weakening them; to give, in short, to works of lead a precision of execution, and a solidity, unattainable up to this time.
Autogenous soldering will also be of great assistance to several chemical manufactures, where it is so important to have large vessels of lead without alloy. By uniting a number of sheets into one, vessels of pure lead of any size may be formed for the process of acidification and concentration of saline solutions; for the formation of scouring vats employed by so many artisans who work metals; for vessels of every kind used to contain liquids which act upon tin solder.
In the repair of leaden vessels exposed to the action of heat, peculiar advantages are offered by autogenous soldering. By the old method, the holes which are so often caused in the bottoms of these vessels, either by the action of sudden flames, or by deposits that form on their surface, can be stopped only when they are not of too large dimensions, by making what are called weldings of pure lead. The cases in which this mode of repair is available, are very limited, and whenever it is impracticable, the boilers must be taken down, the lead changed, and then reset; thus occasioning considerable expense and an interruption to business. By the new method, nothing is easier than to apply pieces to the bottom or sides of the vessels, whatever be the size of the holes, and thus the whole of a boiler may be renewed piecemeal. By this plan, too, the old lead remains uncontaminated with solder, and consequently will yield a pure metal to the melting-pot.
The great ductility of lead, which, in many cases, is one of its most valuable qualities, is, however, an inconvenience when instruments or utensils are required of considerable strength. At the same time, there are circumstances where this metal alone can be employed, on account of the manner in which it resists chemical action. By constructing vessels or instruments of iron, zinc, or wood, and covering them with lead, utensils can be formed that will resist pressure and blows, and most chemical agents, as well as if they were made of solid lead. Such vessels are required in the preparation of soda, and other gaseous waters; in the distillation or evaporation of acid or alkaline solutions; and for many other purposes.
Another application that deserves especial notice is that of lining common barrels with thin sheet-lead. These vesselswould be of great utility in chemical factories, more particularly in the construction of Woulf’s apparatus, and other pneumatic instruments, to which greater dimensions could be given by this means; but they could be employed with singular advantage in the transport of acid and alkaline liquids by sea and land. Sulphuric and muriatic acids are transported in stone bottles, or glass carboys placed in baskets, which, however carefully packed, are liable to be broken, not only with the loss of the acids, but with danger to surrounding bodies. We are told of two French ships that perished at sea on a voyage to the colonies, in consequence of the breaking of some bottles of sulphuric acid.
In the manufacture of sulphuric acid, the use of ordinary solder is impracticable, since it would soon be corroded. The following method was introduced some years ago for forming sulphuric acid chambers, and the concentration pans. Two edges of lead being placed in contact, were flattened down into a long wooden groove, and secured in their situation by a few brass pins driven into the wood. The surfaces were next brightened by a triangular scraper, rubbed over with candle-grease, and then covered with a stream of hot melted lead. The riband of lead thus applied, was finally equalized by being brought into partial fusion with the plumber’s conical iron, heated to redness; the contact of air being prevented by sprinkling rosin over the surface. The autogenous soldering apparatus will greatly simplify the above method.
The advantages to be derived from the new process, are by no means confined to lead: the apparatus may be employed in using for solder either the common alloys, or pure lead, to unite zinc, and iron, and lead, with iron, copper, and zinc. It may be substituted also with advantage for the common blow-pipe and lamp of the enameller in all their applications to the soldering and joining performed by the aid of these instruments by jewellers, goldsmiths, tinmen, manufacturers of plated goods, of buttons, &c.
The flame produced by the combustion of the gas may be most economically employed for heating soldering irons. A few seconds suffice to bring the iron to the desired temperature, and it can be kept at that temperature for many hours without being liable to burn, nothing more being necessary than to regulate the flame by means of cocks, and the workman need not be obliged to change his iron, or even to leave it for a single moment. Hence there is not only a considerable saving in manual labour, but also in fuel, which in most cases is of greater consequence.
Such are a few only of the advantages of this simple and beautiful invention, which is now very extensively adopted inFrance, and will doubtless get into extensive use in this country, when its merits are more generally known.
It may be here stated, in justice to some of our own ingenious countrymen, that after this method had become extensively known, M. Richemont’s claim to the invention was disputed. We have been informed, that previously to the year 1833, aMr.Mallet had employed an apparatus constructed on the same principle, and used in a similar manner, as that already described as the invention of M. de Richemont. InLoudon’sEncyclopædia of Cottage Architecture, published in 1833, the following passage occurs:—“Mr.Daniell, of King’s College, London, has since published the same thing as new, and of his invention: however, I can establish priority by my laboratory journal.”