Bronze casting

“ Every traveller has seen the quaint half-foolish little man, as he stands there holding his two geese who politely turn away their heads in order to produce the streams of water!
With the best bronzes, and with steel used for decorative purposes, the original casting has frequently been only for general form, the whole of the surface finishing being done with a shaping tool, by hand, giving the appearance of a carving in bronze or steel. In Japanese bronzes this is particularly felt. The classical bronzes were evidently perfect mosaics of different colours, in metal. ”

“ Figures that are cast in bronze are done differently. The bust or figure is prepared in exactly the same manner in plaster of Paris, an exact model of what is wanted, and this has to be sent to the art foundry to be cast. That is not the work of the sculptor himself, but of the bronze-workers, and as bronze fetches from seventy to ninety pounds per ton, and it takes two or three tons to make a large figure, it is easily seen that five hundred pounds is quite an ordinary bill for casting a single figure at a foundry. ”

“ Bronzing is sometimes used over paint to give the effect of metal. Thus a piece of iron casting may be painted green or copper color, and then the highest portions of the relief touched with bronze. This is done by coating the article with japanners' varnish or gold size, and when tacky dusting over a little powder bronze, which can be applied by a piece of cloth or velvet rubbed in the powder. The bronze should not be applied to the bare oil paint. The color of the bronze must bear a correct relation to the color of the paint used. ”

“ The following general sketch of the processes of casting will render Vasari’s account more easy to follow. A successful cast in bronze consists in a thin shell of the metal, representing on the exterior the exact form of the model, or the complete design in the artist’s mind. The best way to procure this is to provide first a similar shell, perfect on its exterior surface, of wax, and then to melt away the wax and replace it by molten bronze. For this to be possible the shell of wax must be closely sealed between an outer envelope and an inner packing or core. ”

“ But portrait-statues of bronze may belong to any age; because, while the sculptor in marble is obliged to produce a work of his own hands and conception, and the date of a marble statue can therefore be determined by comparison with other well-known works, the caster in bronze can easily reproduce specimens of142 earlier and better times by taking a mould from a good original, altering the features slightly, and then casting it in excellent bronze. ”

“ Rough lumps of metal have frequently been found with deposits of bronze implements in Britain, these latter being sometimes in a worn-out or broken condition, and apparently brought together as old metal for re-casting. In other deposits the instruments seem new and ready for use, or again they are in an unfinished condition. All the circumstances of these discoveries, however, go to prove that they are in fact the stock-in-trade of the ancient bronze-founders. ”

“ The method of the ancients in casting bronze statues is not described by any ancient writer, but it is supposed to have been this: A fire-proof core was first built up of plaster, clay, earth, or other materials, and over this a thin and even coating of wax or pitch was spread; or perhaps, which is not so probable, the surface was rasped down to the thickness intended for the bronze, and afterwards covered with a thin coating of wax. ”

“ Alfred Gilbert, Onslow Ford, Harry Bates, and others, in place of the method of casting without the use of the wax, which entailed a great deal of surface work and chasing upon the hard bronze, so that the delicate modelled surface—the touch of the artist, in short—was lost, but it is just this which is preserved by the lost wax process, so that it is a method which favours artistic modelling, since it perpetuates it in bronze with greater precision than by the ordinary method, and does not require after touching in the hard. ”

“ CHAPTER IV. HOW TO CONSTRUCT FURNACES FOR CASTING BRONZE, WHETHER FOR STATUES, ORDNANCE, OR OTHER SUCH-LIKE THINGS. Furnaces for casting bronze have to be made by each master according as the special needs of his piece of work require it. Inasmuch as at the beginning of my book I promised always to illustrate what I was describing by work of my own, I will do so with furnaces also. When working for good King Francis, I had to make a great bronze gate, for which a special furnace had to be constructed. ”

“ In considering the various antiquities of the bronze-period, our attention cannot but be struck by the manner in which they are wrought, and the very considerable degree of skill displayed in their construction. The greater part of the objects are cast, but the casting is neither rude nor common. In this point of view a very remarkable battle-axe of bronze requires particular mention. It is sixteen inches in length, and is ten inches broad at the edge. ”

“ The art of metallurgy had made great progress during the bronze epoch. There were at that time considerable workshops for the preparation of bronze, and small foundries for melting and casting this alloy. When once formed into weapons, instruments, and tools, bronze objects were fashioned by artisans of various professions. ”

“ In producing a bronze statue it is necessary first to make an exact clay model. This done, the usual Greek practice seems to have been to dismember the model and take a casting of each part separately. The several bronze pieces were then carefully united by rivets or solder, and small defects were repaired by the insertion of quadrangular patches of bronze. The eye-sockets were always left hollow in the casting, and eyeballs of glass, metal, or other materials, imitating cornea and iris, were inserted. ”

“ It is true that certain Germans and Frenchmen, who vaunt the possession of marvellous secrets, pretend that they can cast bronzes without retouching them; but this is really nonsense, because the bronze, when it has first been cast, ought to be worked over and beaten in with hammers and chisels, according to the manner of the ancients and also to that of the moderns—I mean such moderns as have known how to work in bronze.
The result of this casting greatly pleased his Excellency, who often came to my house to inspect it, encouraging me by the interest he showed to do my best. ”

“ A long blade, somewhat differing in its details from Fig. 245, was found between Lurgan and Moira, Co. Down, and, it is stated, in company with the bronze hilt or pommel shown in Fig. 246. These objects formed part of the Wilshe Collection, and are now in the Museum of the Royal Irish Academy. Two objects, somewhat similar to Fig. 246, found with spear-heads in Cambridgeshire, will subsequently be mentioned. A piece of bronze of much the same form, found with a hoard of bronze objects at Marden, [739] in Kent, seems to be a jet or waste piece from a casting. ”

“ Hermes, the bronze, then answers:—
“It happened lately that my breast and back were covered with pitch by the sculptors in bronze, and a ridiculous cuirass was thus formed on my body, and by imitative art received a complete seal from the brass.”24
This passage is supposed to indicate the process of casting in plaster. It is possible that it may indicate a preparation in pitch to cast in bronze, but certainly not in plaster, which is the sole question. It is not workers in plaster who are engaged on it, but workers in bronze ”

“ The art of the bronze caster is a very old and interesting one. The method of proceeding has varied very little with the centuries. A statue to be cast either in silver or bronze would be treated in the following manner.
A general semblance of the finished work was first set up in clay; then over this a layer of wax was laid, as thick as the final bronze was intended to be. The wax was then worked with tools and by hand until it took on the exact form designed for the finished product. Then a crust of clay was laid over the wax ”

“ The advantages resulting from the above properties will be obvious to all artists in bronze. They are chiefly the result of the use of lead as one of the chief constituents of the alloys. The low melting-point of these bronzes, their fluidity when melted, and the facility with which they acquire certain patinas are indeed entirely due to the use of this metal. The fine velvety surface and sharpness of the castings depend in a great measure on the structure of the mould and its comparatively high temperature when the bronze is poured into it, although partly also on the influence of the lead. ”

“ This finished, the craftsman puts the mould under ground near to the furnace where the bronze is melted, propping it so that the bronze may not strain it, and he makes the channels through which the bronze is to flow, and at the top he leaves a certain thickness, which allows for the surplus of the bronze to be sawn off afterwards, and this he does in order to secure sharpness. ”

“ Steel when heated to redness and then dipped in cold water becomes so intensely hard, that tools treated in this manner have to be somewhat tempered, or softened by heat, before they can safely be used; while to soften copper the usual method adopted is to make it red-hot and dip it in cold water. In whatever way the metal was drawn out, some of the large vessels of the transitional period between Bronze and Iron, such as those from Hallstatt, are wonderful examples of skill in working bronze. ”

“ This may also be regarded as a characteristic specimen of the socketed celts usually found in England, though the second moulding is often absent, and there is a considerable range in size and in the proportion of the width to the length. No doubt much of this range is due to some instruments having been more shortened by use and wear than others. The edge of a bronze tool must have been constantly liable to become blunted, jagged, or bent, and when thus injured was doubtless, to some extent, restored to its original shape by being hammered out, and then re-ground and sharpened. ”

“ Minute examination of the bronzes themselves will be found to throw fully as much doubt on the probability of a common origin for the mixed metal, as for the weapons into which it has been fashioned. The difference even in colour and texture is very great, and in some cases still only imperfectly accounted for. Many of the bronze weapons found both in Scotland and Ireland, are of a bright yellow colour, like brass, or rather resembling gilded metal; it does not tarnish, and, on analysis, is found to contain no zinc. Others are more of a copper colour, also little liable to tarnish or corrode ”

“ Very stiff and very elastic, tougher than iron, very little acted upon chemically, and in certain cases not at all, capable of being cast like ordinary bronze or brass, forged like iron and steel, of being worked in every way like the most malleable metals or alloys, having, added to these properties, a color analogous to that of the most precious metal, this bronze proves itself adapted to uses almost innumerable. ”

“ It may be that for personal decorations the jet and amber, which during our Bronze Age were so much in fashion for ornaments, suited the native taste better than decorations manufactured from the same metal as that which served for tools and weapons; and that when metal was used gold had the preference. At the same time, for useful articles, such as some kinds of pins, bronze may well have served, and it is to be observed that no pins decorated with gold have as yet been found with bronze weapons in Britain, though they have occurred in other countries. ”

“ In due proportion it will transform soft, yielding copper into bronze, which makes the best weapons of the age. The art of tempering iron is still unknown, and swords and spear-heads of bronze still decide the battles of the ancient world. Alike in peace or war, tin is sought and prized as gold is to-day. ”

“ According to the Arundelian Marbles, iron was discovered b.c. 1432, [54] or 248 years before the taking of Troy, but though we have occasional mention of this metal and of steel in the Homeric poems, yet weapons and tools of bronze are far more commonly mentioned and described. Trees, for instance, are cut down and wood carved with tools of bronze; and the battle-axe of Menelaus [55] is of excellent bronze with an olive-wood handle, long and well polished. ”

“ As soon as the metallurgic art had taken root among the prehistoric people of Europe each country began to manufacture its own bronze objects, modelling them, in the first instance, after their analogues in stone, or imported metal specimens. Such a derivative connection can be traced not only between the flat bronze axe and the stone celt, but also between most of the other bronze implements and weapons and their prototypes in non-metallic materials. ”

“ Many of the great works of the old masters in bronze are unique, and they are retained as great treasures in the national museums where they have found lasting homes. For the benefit of connoisseurs of art many of the great works have been copied, and in the Victoria and Albert Museum at South Kensington and in other places there are replicas in metal and in other materials, faithful copies of the original bronzes which are so rare. The educational value of a gallery of ancient art, whether expressed in marble, bronze, stone, or other materials, is considerable ”