This last process is borrowed from the Belgians. In the working of their extremely fine Damascus barrels, they found a very great difficulty in staining them so as to produce a clear and distinct figure. The way they now proceed is either to eat away the particles of iron, leaving the steel prominent and the barrels bright; or they polish them extremely fine from end to end, and then blue them in a stove with charcoal. The process is thus described in the notes to a German translation, by Dr. Schmidt, of Weimar, of my last edition of the “Science of Gunnery.”
“The method of browning the Damascus barrels, which are so much admired in England for their distinctness in colour and beauty of figure, is obtained very simply: namely, first burnish the barrels very fine; then cover them with bone oil; pound, or drop, or strew wood-ashes all over; then heat them in a cage of wire filled with charcoal, until you obtain a dark first blue; after they are cold, mix a small quantity of sulphuric acid in water (a quarter of a pint with so many drops); then take a hard brush and apply it to the barrel, when the acid will extract the colour from the steel, leaving the iron with its greater adhesion covered with the blue colour. Great care must be used and skill displayed to keep a good colour and not to extract too much.”
This we cannot do, because we solder with tin.
The “Belgian Damascus” barrels are generally “eat up,” as it is technically termed. “Pickled” is the term also used to describe the process, which is simply eating away the softer metals from around the steel or harder material. The best preparation for this purpose is 1 lb. of the sulphate of copper (known as blue vitriol) dissolved in a gallon of soft water, at the boiling point, and continued boiling in an earthenware vessel, until the quantity is reduced by evaporation 25 per cent.; let it cool, and then pour it into a leaden trough or bath. The barrels, when properly secured at the muzzle and breech-ends to prevent the liquid getting into the interior, are immersed therein. The solution will act sufficiently upon the metals in the space of from fifteen to twenty minutes; care being taken to remove and carefully wash them with cold water, and then, after observing the progress of the pickling, re-immersing them as before, until the operation is complete. Then pour boiling water over them, and scratch them well with a steel brush, which will eventually give that beautiful bright “wavy” surface much admired by many people. Laminated steel barrels also look very well, after being subjected to this operation.
Having now detailed as much of the “modus operandi,” as the patience of the reader will admit, I shall endeavour to give a peep into the “sanctum sanctorum” of the gun-makers’ workshop. I have shown in detail what course ought to be pursued in the construction of guns of the best quality only; and before proceeding further shall finish this part of the subject. I am not, as some would say, “going to expose the whole secrets of the trade:” oh no, only a portion.
There are six qualities or varieties of mixtures of iron for barrels of best quality. The plate-facing contains two kinds finished, composed of steel entirely, but of different degrees of carbonization; one is composed entirely of a laminated series containing many scores of distinct laminæ in the thickness of the sides of the barrels, twisted and beat into tortuous shapes. The other, of larger laminæ, but showing the edges of the laminæ at an angle with the length, and thus appearing larger than, if presenting the side or end of the plates.
Care must be taken that the great proportion of the fibres shall always run round the tube, so that the greatest portion of strength may be obtained, together with a beautiful figure. The cost of this arrangement is considerable, as it involves a great waste of metal, and occupies a considerable time to work and re-work—twisting, faggoting with the bars placed in various forms, at acute angles to each other, at right angles, plaiting three or four rods together, as a lady does her hair, cutting these into pieces, faggoting and welding them into one, and, in short, undergoing an endless routine of manipulations, which it would be strictly unprofitable to detail, but are all productive of cost. An ingenious man may work and improve metal of this nature until its cost equals the price of silver; and, if judiciously done, improving it still, even until he has wasted 90 per cent. of the original material.
The ultimate characteristics and properties of iron have, as yet, never been ascertained: it is capable of being condensed until it becomes nearly, if not quite, equal to the specific gravity of silver or lead. No pursuit, mechanical or philosophical, presents so great and so beneficial a research, to the whole civilized and scientific world, as iron. I could twist and retwist iron, until, from the beautiful and interesting results, it would become with me a sort of monomania. I wonder not at the variety of patterns in a Damascus sword-blade: the mind conveys me to the scene, and a regret arises that I did not live in those times; yet still it is but a mechanical arrangement directed by an ingenious mind, and the ultimate benefit, apart from the beauty, is more than imaginary. However, it proves that the Orientals were artists, and that they were appreciated: were this the case now with us, we could do all they ever did, and more.
Laminated steel is now a great fact. It is a name stereotyped in Belgium, Germany, France, and America, as well as in the place of its birth—England; and orders come from all quarters of the globe for the celebrated laminated steel. Every writer of eminence is loud in its praise, and justly so too; for about its merits there is no mistake. No combination of metals ever yet before tried since the birth of gunnery, can equal it, either in density, ductility, or tenacity. A laminated steel barrel has never been known to burst. “Reputed” laminated steel barrels have been burst, but no real one ever. Nor is it probable, save from malconstruction. Through inattention in the welding the best of metal may be burnt; but the better the iron, the greater the difficulty. Steel is more liable to melt than burn; so that, with care and skill on the part of the workman, it will very seldom indeed occur. But that chance is provided for, as far as human judgment can do, in entrusting such barrels only to first-rate and steady workmen. Such men are no doubt, to a certain extent, scarce; but they may yet be found: the Birmingham welder of proved skill and ability is inferior to none in the world. Laminated steel barrels are more scarce than welders.
Although the various manufacturers of Europe have complimented me by adopting the name of my invention, yet I am sorry to add it is but in name: there are very few even tolerable imitations of them. The cost is the “bugbear:” the name costs nothing, and can easily be assumed; but to make laminated steel barrels is quite another matter: it touches the pocket, and interferes with the profit; and it is only in very rare cases indeed—although the order may be explicit as words can make it—that the real article is supplied. There are very few makers in Birmingham who in reality make “laminated steel.” Steel barrels are more plentiful: they care not so much for the price of the metal; it is the after repeated manipulations that are evaded: the labour and loss of material is too much, and is necessarily “shirked,” and argument is always met with the answer, “We see nothing in it.” Yet the words “laminated steel” are to be found engraved upon barrels of the lowest quality of iron of which double barrels are made. Iron twist is subjected to a similar process to that already described as employed in producing Damascus iron, and which may be termed common iron Damascus. Thousands of guns are made from this kind of metal, and yearly sent to the United States of America; yet all are unblushingly represented as “laminated steel barrels.” The actual price charged for these sort of guns in the United States I know not, but have no doubt for the whole gun it is about equal to what would be the prime cost of a pair of real laminated steel barrels alone.