Fig. 16. Blowpipes.
Fig. 17. Solder-dish.
When filed solder is used, the process of charging the article is rather different from the above. In the latter case the filings are commonly put into a small cup-shaped vessel (Fig. 17), in most cases the bottom of a tea-cup, or some other similar vessel, being used for the purpose; a lump of borax is then takenand rubbed upon a piece of slate, to which a little water is occasionally added during the rubbing; when this solution attains the consistency of cream, it is put into the solder-dish and well mixed with the solder. This is then applied to the article to be soldered, by means of a charger, consisting of a piece of round metal wire, flattened at one end, and shaped for the purpose it has to serve. The joinings, when this kind is employed, require no boraxing with the pencil, as described under pallion solder; the borax being intermixed with the solder flushes with it through the joinings to be united, thus rendering any further application unnecessary. The process to which we are alluding is called “hard soldering,” and cannot be applied to metals of a fusible nature; neither must it be attempted in the case of goods bearing the name of plated, which are put together with soft or pewter solder, similar to that used by tinsmiths and gasfitters. If there should be any soft solder about the article, to be soldered by the means we are describing, it would be almost certain to destroy it, the soft solder having such an affinity for entering into combination with metals more infusible than itself when overheated.
There is an art in soldering greater than some people would believe. The heat required is of various degrees, some articles requiring a broad roughflame, others a smooth one, and others again a fine pointed one. All these circumstances connected with the process, together with others which we could detail, proving that it is an art only to be acquired by practice, must be considered enough; and we proceed to observe that the skilful jeweller in soldering a large piece of work will direct the flame of the gas jet to all parts of it, until it is tolerably hot, and then return to the spot to be soldered, and by a very dexterous movement of the flame, produced by the blow-pipe, increase the heat at that spot until the solder has flushed and the parts are rendered thoroughly secure. So far as some of the work of the silversmith is concerned, the process of soldering is a very delicate operation, and ought not to be undertaken by an unpractised hand.
The method of preparing solder for filigree work is worthy of a passing notice. It is called by the Germans Lemaille solder. In the first place it is reduced to very fine filings, mixed with burnt borax powdered fine, and in this state it is sprinkled from a spouted grater over the work to be soldered. The English filigree workers commonly use clean filed solder, and by means of the camel-hair pencil apply a solution of borax to the work, and then sprinkle the dry solder upon it from the grater.
In Vienna a kind of powdered borax is employed, calledStreu borax, or sprinkle borax. It is composed of the following ingredients, which should be gently annealed to expel their water of crystallization, the whole well pounded and mixed together, and sprinkled over the parts to be joined from the spouted grater as before:—
The object of this mixture is to prevent the rising of the solder, and to facilitate its flushing. Too much of it should not, however, be put with solder in the grater at one time, as it is as objectionable as too much borax applied in the ordinary way, but every workman will learn from experience concerning these matters. We have tried this mixture, prepared with filed solder in the ordinary way, and found it advantageous at first; but its greatest drawback is the turning of the solder yellow if not quickly used upon the work after mixing, thus rendering the solder permanently injured. For this reason we have had to abandon its employment in the wet state. But, in its dry state, to the silversmith for filigree purposes it is likely to be ofadvantage. It may be remarked that this preparation encumbers the work with a great deal more flux than borax does, and consequently it requires to be more often boiled out during the period of soldering together the component parts. This is effected by boiling in a weak pickle of sulphuric acid and water, composed of the following proportions: one part of acid to thirty parts of water.
CHAPTER VIII.
On the Melting of Silver.
The processes of melting and properly mixing silver with its alloys in a crucible are among the first operations of the silversmith, and are, moreover, of great importance in the production of intimate and homogeneous alloys. In order to effect these, however simple they may appear, various precautions are necessary, and certain principles require carrying out to arrive at the best possible results, otherwise a great loss or waste of material may take place. To direct attention to those principles, which from very careful attention to the subject we have found to answer best, will first be our aim, and if we succeed in rendering some little service to our fellow-workers in the craft to which our toil and leisure have been devoted we shall feel highly gratified.
The weighing of the component metals, the selection of the crucible, the charging of it, andthe attention it requires whilst in the furnace are considerations to which we cannot too strongly call attention. The regulations with regard to weighing should be strictly and accurately carried out. The best and safest plan is, after the various metals have been separately weighed, to re-weigh them, this time collectively, in order to ascertain whether the total weight corresponds with the previous calculation; if it does, the mixture has been properly prepared. We have known both time and trouble saved by the adoption of this precaution, after mistakes had occurred which could not have been detected until the weighing of the bar of metal had taken place after melting. There are various kinds of crucibles manufactured for the use of the precious metal workers. Crucibles were so-called from originally being impressed by the alchemists with the sign of the cross. They are calculated to bear very high temperatures, and consist of English, Hessian, Cornish, Black-lead, and Plumbago. The last two are by far the best; the plumbago, however, being the hardest, and capable of standing the highest temperature, is to be preferred before all others. It will also stand more frequent meltings than any of the rest. Such crucibles have been known to withstand the heat of the furnace for upwards of fifty times withoutgiving way. The wear of them is very strong and resisting, as they onlygraduallybecome reduced in thickness, so that it is easy to distinguish their unfitness for use. Fluxes act on earthern crucibles, particularly English at a high temperature, whilst nitre and carbonate of soda soon destroy them.
Fluxes are necessary in most cases of metallic reductions: they protect the metal from the air, and dissolve impurities. They are of several kinds, as follows:—
Vegetable charcoal.Carbonate of potash.Carbonate of soda.Common salt.Sal-ammoniac.Sal-enixum.Saltpetre.Borax.Sandiver.Yellow soap.Black flux.White flux.Crude tartar.Brown potash.Sub-carbonate of potash.
All these fluxes have occasional duties to perform, and are therefore of great service to the metallurgist.
To prevent the cracking or flying of the crucible, when newly employed, it should, before being charged with the precious metal, be well annealed; that is, heated to redness upon a very slow fire—onethat is gradually going down, and in which there is no blaze is to be preferred, because the flame has a tendency, on the introduction of a new crucible, to make it fly to pieces. When it has become red hot, if a cold bar of iron be introduced it will soon show whether there are any cracks, and if so the crucible should be rejected; on the contrary, if it withstands this test it may be placed aside until required for use, when it may be employed with perfect safety in the melting of silver and its alloys.
When copper and silver only form the alloys of the silversmith, they should both be added to the crucible at the commencement of the operation; and it is the best plan to put the copper at the bottom, because it is the most infusible metal. By doing so, it will receive the greatest degree of heat, which in jewellers' furnaces always comes upwards and the higher specific gravity of the silver has a tendency to force that metal downwards; consequently, when the two metals have become fused, upon well stirring—which should be done with an iron stirrer tapered at the point, and previously heated to redness—a perfectly homogeneous mass will be the result. When the more fusible metals of which we have spoken are to form the component parts of the mixture, differenttreatment with regard to them will be required. They should not be added at the commencement of the operation, but should be dealt with afterwards, in the following manner:—
Zinc is one of the more fusible metals, and is sometimes employed by the silversmith in his alloys, for the purpose of imparting a greater degree of whiteness to them, as well as rendering inferior silver more easily bleached or whitened; thus assisting to bring back the natural colour of fine silver to manufactured articles, which have partially lost it by the addition of alloy of some other colour. Zinc, when employed in silver alloys, should be cautiously used, and care should be taken not to add too much to a given quantity of material. The solder used with silver-zinc alloys should be far more fusible than that employed with the other alloys. If too much zinc be added in the preparation of these alloys, in the course of the work, particularly in the process of soldering, they have a tendency tosweat, and sometimes toeatthe metals into holes around the parts to be united; such alloys, therefore, render this process very difficult to perform, besides entailing more labour in the production of a clean and smooth finish.
Fig. 18. Plumbago Crucible for melting.
In melting an alloy of silver, copper, and zinc, the silver and copper should first be melted in a plumbago crucible of the form shown inFig. 18, and well stirred together in order that they may become properly mixed. The zinc is sold in flat cakes under the name of spelter, and, when required, is usually cut up with a chisel into pieces of various weights suitable for the object in view. When the copper and silver have become well incorporated, the mixture should be protected from the air by a suitable flux, charcoal being the best for this purpose. The most suitable time to add it to the crucible in the furnace is when the metals are just beginning to fuse. This flux covers the whole of the surface of the molten mass, and so prevents the action of the air from destroying some of the baser metal. The charcoal should be perfectly pure and in a finely divided state, for if adulterated with any gritty matter (and sometimes such is the case) a very indifferent working material is produced, the evil results of which show themselves in every stage of manufacture. These instructions with regard to melting the more infusiblemetals having been carried out, the zinc is taken with a long pair of tongs (Fig. 19), and held within the furnace, over the mouth of the crucible, until the temperature has almost reached the melting point, when it should be carefully dropped into the fused mass below, quickly stirred, so that it may become intimately mixed with the other metals, and at once withdrawn from the furnace and poured into a suitable ingot mould (Fig. 20). The ingot mould should be clean and smooth inside, slightly greased, and dusted over with fine vegetable charcoal; this latter substance prevents the metal from adhering to the sides of the mould. It is, perhaps, almost unnecessary to state that the ingot mould requires heating to a certain temperature before the melted composition is poured in,otherwise serious spouting takes place, resulting in a great loss of metal. On the other hand, the operator should be cautious not to over-heat it, as the same evil consequences may result.
Fig. 19. Tongs for Melting.
Fig. 20. Ingot Mould.
The bar of metal upon cooling should be weighed, and the difference—as most meltings show a little—noted. This isloss, but it will be very little, if the above instructions have been strictly adhered to from the beginning of the operation. With the charcoal flux we have referred to, very nice and clean bars of metal can be produced. This flux is always floating upon the surface of the mixture, and, with a little dexterity in the pouring, it can be prevented from coming out of the crucible with the metal; its proper place is at the end of the pouring. When tin is employed, either in alloys or solders, its treatment is similar to that described for zinc; such alloys should not be kept too long in the furnace after they have become fused, as they rapidly become oxidized, especially if brought into contact with the air.
The waste in silver, and in fact of all alloys, is entirely dependent on the duration of the time of fusion. If it is prolonged after the addition of the fusible metals, the loss is greater in every case, than when once melted. The metals should be subjected to the beat of the furnace for the shortestpossible period. The alloys of silver with zinc would lose more than the alloys of silver with tin, because zinc rapidly volatilises when heated above the temperature of its fusion, and this is especially the case when it enters into combination with silver and copper in the fused state; its vapours can be seen to rise and burn in the air, producing light and white flaky fumes, and, chemically speaking, forming theprotoxideof zinc. With care and manipulative skill during the process of fusion, the proportion of waste can be reduced to a minimum; and when this is exactly ascertained an allowance can be made in the preparation of the mixture for the crucible. From the above remarks it will be apparent that when both tin and zinc form component parts of a mixture, either to be used as an alloy or as solder, the tin should be added to the other metals, and well stirred, so as to obtain an intimate mixture, before the addition is made of the zinc.
Scrap silver should be carefully sorted before undergoing the process of re-melting, and if possible all foreign substances removed. It may, if preferred to work it in that way, be melted into a separate bar, or otherwise used as an addition to a new mixture. When, however, it is separately melted, a flux, such as carbonate of soda, may beemployed, on account of its cheapness, in small proportions to the charcoal flux already alluded to. In brittle and troublesome alloys we have found charcoal and a small quantity of borax extremely effective. Saltpetre is a very useful flux in dissolving impurities, but in some alloys its presence is injurious. Sandiver will remove iron or steel from the mixture. Corrosive sublimate destroys lead and tin. We have found the sub-carbonate of potash one of the best fluxes for silver, when matters have not been quite so straight as they should be in the working of the metal; it is used in melting the difficult alloy of 18-carat gold, and is considered a secret not generally known to the trade. Sal-ammoniac is an excellent flux for producing clean and bright ingots and tough alloys. We invariably use it with all our alloys, mixed in small quantities with charcoal, and prefer it to all others.
Lemel, that is the filings and turnings produced during the process of manufacture, should have quite a separate method of treatment. It is best prepared for the crucible by passing it through a fine sieve, afterwards thoroughly burning it in an iron ladle, and then intimately mixing it with a flux of the following nature and proportions:—
Fig. 21. Fire-clay Crucible for Lemel.
The sal-enixum prevents the rising of the mixture in the crucible—which should be of the skittle shape (Fig. 21)—and keeps it from overflowing; it also possesses a refining capacity the same as saltpetre, and is much cheaper. The burning of the lemel has a great tendency to destroy all organic matter that would be likely to cause the mixture to overflow during the period of fusion; but if such a thing should be at all likely to take place, the addition of a little dried common salt would remedy the evil, a small quantity of which ought always to be provided for the purpose. The common carbonate of soda is also a cheap and useful flux to the silversmith. Five-sixths of the above flux should be well mixed with the stated proportion of lemel, then placed in the pot, and the one-sixth remaining placed upon the top of the mixture, when it may at once be transferred to thefurnace. Great heat is required in this operation, and it also requires careful supervision to prevent, if possible, waste of material. When the mixture has become perfectly liquid, the heat of the furnace should not be allowed to decrease, but continued for half an hour longer, and if the use of it be not further required, the fire may then be allowed gradually to die out. The mixture will require repeated stirrings during the period of fusion, in order to dissolve such portions as might otherwise not come immediately under the action of the flux. When the operation of fusion has been completed, the crucible is withdrawn and allowed to cool, the solidification of the metal is then perfect, and it may be recovered by breaking the pot at the base, when it will fall out in a lump corresponding with the shape of the crucible. The lump of metal should then be carefully weighed, the loss ascertained—which always varies in proportion to the amount of organic matter contained therein; it may then be sold to the refiner, or exchanged for new metal.
In this process it will be observed that the crucible is broken every time a fusion takes place, consequently some little expense is incurred in providing crucibles for the purpose. To obviate which the following plan may be economically andsuccessfully employed; and especially when the metal is sold to the refiner by assay, the method about to be described will be found most advantageous, for it should be borne in mind that the lump of metal from the previous fusion has to be again run down in another crucible and poured into an ingot mould before the refiner will consent to take his assay from it. In this latter process the whole work is performed in one fusion, and the expense of a new crucible thereby saved. The flux employed in the reduction of the metal is also considerably reduced. The plan is performed after the following manner:—
Fig. 22. Plumbago Crucible for Lemel.
Take a plumbago crucible of the shape shown inFig. 22, and capable of holding the required mixture; put the lemel into it, and then place on the top one ounce of finely powdered carbonate of soda; this is all the flux the mixture requires, and it is then quite ready for the furnace. When the lemel has become properly fused, for facilitating which it is repeatedly stirred with a thin iron rod, it is withdrawn and poured into an ingot mould prepared for it as previously described. Theflux and other organic matter, which always accumulates upon mixtures of this kind, is held back by the timely application of a thin piece of flat wood to the mouth of the crucible. After the withdrawal of the bar of metal from the ingot mould, it is cooled and weighed, and then it is quite ready for the operations of the refiner.
CHAPTER IX.
On the Working of Silver.
Having reached a most important and very interesting part of our subject, viz. the working of silver, and being desirous of making this treatise useful to the silver-worker in all the branches of his art, it is our intention to enlarge upon these processes—which are purely mechanical—and somewhat minutely to describe the various manipulations and arrangements required in the production of the wares of the silversmith.
After the removal of the bar of metal from the ingot mould, it should be plunged into a vessel of cold water, dried, and then carefully weighed. At this stage of the process it is ready for the operation of rolling. This process, so far as it concerns large ingots of the metal, is a distinct branch of the trade, and is carried on in separate premises established by certain firms for the purpose. These establishments are called “rolling-mills,”the machinery used in them (which is powerful and costly) being moved by steam-power, the reduction of the bars of metal to their various sizes is soon effected. The very thin ribbon-shaped metal is produced by submitting it to the action of rollers of smaller dimensions, one after the other, until the desired thinness is obtained. The bars of metal are taken to these mills by a man whose special duty it is to watch over them during the processes of rolling and annealing, otherwise it would be very easy to have an ingot of gold or silver exchanged for one of base metal, the mill companies not being responsible for the material intrusted to their care for rolling; hence the necessity for the porter’s services, to watch over his employer’s interests. To prevent accidentally exchanging the bars of metal, through their great similarity to each other, it is the usual thing for the men in charge of them to put a special mark upon the property of each person, previous to the process of annealing. This mark is applied by means of a piece of chalk or soap, and is not removable by heat. The annealing is performed in large iron muffles, heated to redness and kept in that condition by flues; the bars which require annealing being placed upon a piece of sheet-iron which slides into the muffle, and there they remainwith the doors closed until they have become red hot. It is more particularly during this operation that each person’s property requires marking and watching, because of the number of bars admitted at one time into the muffle; and unless the greatest care be exercised at such a time some mistake is almost sure to occur.
A register is kept of the weight of the metal sent to the mill for the purpose of being rolled into the required shapes and sizes by the manufacturer, who afterwards works it up into different wares and utensils. The metal is also weighed on its admittance to the mill, by the clerk of the works, and again on its passage out, and a comparison of the weights registered; but in Birmingham, in some cases, this has been so irregularly performed that great discrepancies have actually taken place in the weights at times, and it has led to the establishment of another rolling-mill for gold and silver, in which the proprietors take upon themselves the whole responsibility and care of metals intrusted to their charge for the above purpose. The method pursued by them in respect to their business is as follows: A manufacturer sends a bar of metal to be rolled, carefully noting the exact weight and size to which it is to be reduced upon a properorder head. This weightis carefully tested at the mill, and if found correct, an invoice is given in exchange, upon which is entered the cost of rolling and the time when the work will be completed. The messenger then goes away, returning at the time stated to bring away the rolled metal.
The advantages this system presents over the others are obvious; the return of the full weight of the metal is guaranteed by responsible persons, the messenger is at liberty during the time occupied in rolling to follow his other duties, the weighing of the respective metals is far more accurately performed both in and out of the mill, besides greater satisfaction being given both to the manufacturer and the roller, the reciprocation of confidence between each, being among some of the additional advantages which might be enumerated. Messrs. Kemp, of Birmingham, deserve the thanks of the jewellery community for their enterprising efforts in the establishment of a system so admirably suited to the requirements of the trade.
The following table gives the charges at the present time for rolling bars of silver:—
Table of the Cost of Silver Rolling.
It is a usual thing at all rolling establishments to provide slitting-rolls for those who choose to avail themselves of that mode of cutting up their metal. These rolls are used for the purpose of cutting stout bars of metal into strips suitable for wire-drawing, thus dispensing with the older process of cutting with a pair of vice shears, which method was slow and somewhat uncertain in the production of good work. The slitting-rolls consist of circular barrels, after the manner of the “breaking-down” rolls, only of course much smaller in diameter, and with this exception, the slitting-rolls have square grooves cut into each barrel, the projecting portion of each corresponding with the hollow of the other, whereas the breaking-down rolls are perfectly smooth and plain. Rollers somethingsimilar to those we have described are used by wire-drawers to facilitate the speedy reduction of the metal, the difference being in the construction and action of the grooves. In the grooves of the latter, which are inserted farther apart, the hollows take a half-round shape, and unlike the slitting-rollers, during the revolution of the barrels, the grooves in this case directly meet each other, and thus produce a strip of wire almost round. It is almost needless to remark that wire-rolling requires some amount of practical knowledge to perform it properly. The manipulations indispensable to the art of silver working are so varied and so numerous that we are at a comparative loss which part of the process to consider first; however, if we follow the course of the workman with regard to the production of the various manufactures of his art, we shall perhaps not be far wrong in our desire to effect the purpose we have in view.
In commencing to enlarge upon these mechanical processes we may at once state that it is our intention to refrain from going into the whole art of wire-drawing, because that process has been somewhat minutely alluded to in our other work recently published in the interests of the goldsmiths; the details of which are there fully described.
Fig. 23. Draw-plate.
The draw-plate,Fig. 23, which is the principal tool of the modern wire-drawer, was unknown in this country until the middle of the sixteenth century, when it was introduced by Christopher Schultz, a Saxon, from France. It was supposed to have been the invention of a native of that country named Archal. The draw-plate had been in use some years on the Continent previous to its introduction into England. The old method of making wire was upon the anvil, by means of the hammer; and those who manipulated in this art were termed wiresmiths at that period. The best form of draw-plate consists of a piece of steel about nine or ten inches long, one and a quarter to one and a half inch broad, and about half an inch thick, each containing a number of conical holes of various sizes, becoming smaller in succession until the last hole in the plate is reached, when another plate, corresponding in size, having smaller graduated holes, is employed, and the wire drawn through it; and so on, until the proper size has been obtained.
Fig. 24. Draw-bench for Wire.
Fig. 25. Draw-tongs.
Fig. 26. Drum used by wire-drawers.
Fig. 27. Skeleton Frame or Swift used by wire-drawers.
The drawing of stout pieces of wire is effected very readily by means of the draw-bench (Fig. 24), and the thinner pieces, by the application of draw-tongs (Fig. 25), held in the hands of the operator, and made to do service by swinging the body backwards. Very fine wire is now drawn by means of an apparatus called adrum(Fig. 26), revolving upon a perpendicular pin, the exterior of which receives the wire and prevents it from becoming entangled. When the end of the wire has finally passed through the draw-plate, the whole coil is carefully removed from the drum (which is made slightly conical in form for facilitating the process) and placed upon a skeleton frame made to receive it (Fig. 27); it is then inproper form for its passage through the next hole of the draw-plate.
In the production of very fine wire, the metal, after passing a few times through the draw-plate, requires annealing, as its fibres become so condensed and hardened that it is impossible to repeat the operation without some risk of the wire breaking. For fine wire the annealing is repeated five or six times during its passage through the draw-plate; for stouter kinds the annealing need not be so frequent. This process produces a scale or oxide upon the surface of the wire, which should be removed before the continuation of the drawing takes place, which is generally done by an immersion for a time in very dilute sulphuric acid pickle; or its passage may be assisted through the draw-plate by the application of some lubricating substance, such as beeswax, or a mixture of beeswax and oil, which enables it the more readily to pass through it. In the progress of the wire-drawing the holes have a tendency to become enlarged; these are made smaller again, by repeated blows upon the front of the plate with a somewhat pointed hammer (Fig. 28), and then opened from the back with a tapered steel punch, such as is shown in the woodcut (Fig. 29). The hardening and tempering of the punch is ofimportance. A gauge-plate is used in all establishments for the purpose of determining the size of the wire. The hammering should not take place upon a hardened draw-plate, as it would fly to pieces: it is only those known as soft which should receive such treatment; and those, by a continual alteration of the holes, gradually become hard and require annealing at intervals.
Fig. 28. Knocking-up Hammer.
Draw-plates for wire-drawing purposes are mostly cylindrical in form, but they are employed in various degrees of fineness and in different shapes; such as oval, oblong, half-round, square, fluted, star, sexagon, triangular, and other complex sections, for the production of corresponding wires, all of which receive similar treatment to that above described.
Fig. 29. Round Steel Punch.
The process of wire-drawing, in connection with the art of the silversmith, is more particularly employed in the manufacture of chains, in which branch a very large quantity of silver is consumed. This branch of the craft is almost a purely mechanical one, but, nevertheless, there are some designs inchains which require a considerable knowledge of art for the proper execution of them. It is, however, in “wrought” or hand-made work that true art is made to play so conspicuous a part; for it is here that perfect workmanship, together with great skill and taste, are required in the manufacture of an article. “Wrought” work was one of the earliest productions of the goldsmith and silversmith, and it still remains the trueartisticmethod, although it has been superseded by others of a less expensive character; such as stamping, chasing, engraving, enamelling, casting, &c., to which the older processes of ornamentation and decoration by means of hammering have given place.
Fig. 30. Hammer for Wrought Work.
Fig. 31. Sparrow-hawk.
Wrought work is produced by hammering and soldering the various pieces or ornaments together; and one of the very first things to be attended to in the production of this kind of work is proportion, a knowledge of which is indispensable to true art-workmanship; for the piece of metal which is to be operated upon by the hammer should be of the proper size, so as to require none to be cut off afterwards. Every portion of a designshould be wrought out of the piece of metal separately, and soldered in its proper place upon the article in process of manufacture. When circular forms have to be raised or flanged by the employment of the hammer, as in the case of a raised or flanged brooch “bezil,” themodus operandiis as follows:—Take a piece of metal of the exact size and shape, turn the two ends together from the longitudinal direction, and unite them by soldering; when this is done, the circular band of metal is taken and flanged by means of the hammer and a miniature anvil, placed upon a stout piece of wood which the workman renders secure by placing between his knees, the pressure of which retains it steadily in its place during the various manipulations performed upon it; this kind of tool is termed a “sparrow-hawk”—a representation of it is given inFig. 31. The work is effected by a series of blows dealt with the hammer in regular concentric circles, the bezil all the time gradually working round the pointed end of the sparrow-hawk. It requires great skill and practice to produce the proper shape, and to keep all parts of themetal of equal thickness. The bezils may be produced in this manner round or oval, as well as other complex shapes; the hammering taking place according to the shape required. When raised or ornamental brooch bezils, such as concave or convex patterns, are to be made, the means adopted in their execution are somewhat more complicated than the mode of flanging above alluded to. A tool called a “swage” is employed, which partakes of many forms, the pattern or ornamental device which the metal is required to take being the shape of the swage, or otherwise cut upon it. The metal is easily raised to take the proper design, by a very careful application of the hammering process.
Sometimes in silver-working the form of the object to be manufactured is of such a nature as not to allow of the use of the swage tool, and this is more particularly the case in the manufacture of plate. Such things, for instance, as cups or tankards which have raised ornamental surfaces, and which have to be executed after the vessel is roughly finished, require altogether a different tool for the effecting of such purposes. The one commonly employed in operations of this description consists of a bent piece of steel, upon one end of which is cut the device required; this end beingturned up to the required height for raising the design, and the other end being bent in an opposite direction, which, when required for use, is secured in a vice. The workman, in executing the design upon the object in hand, places it upon the “snarling-iron” (for such the tool is called) at the part to be raised, and there holds it securely while another man strikes the piece of steel at the top of the angle, or just above where it is secured in the vice, the reaction of the steel wire then throws out the metal, in accordance with the device or pattern cut on the end of it. Designs are only roughly raised in this manner, the perfecting of them being performed by the application of various kinds of chasing tools. To prevent a change in the form of the object undergoing this operation, it is filled with a composition formed of pitch, resin, and brick-dust, in the following proportions:—
The preparation of the cement is as follows:—Reduce the brick-dust to a very fine powder, and pass it through a fine sieve; then take the other ingredients and melt them in an iron ladle or othersuitable vessel over a slow fire, stirring them well together; when this has taken place, the mixture will present a thin liquid appearance, which is the time for using the brick-dust. This should be added in small quantities at a time, and well stirred together, until the mass has become tolerably thick. It is then poured out either upon the floor, or into some suitable vessel provided for its reception. While undergoing the operation of chasing, the lower part of the object is preserved from injury, by being laid on a sand-bag. The illustrations, Figs. 32 and 33, represent the snarling-tool, and its mode of application to the work of the silversmith.