doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Not Twist but "Twisted" barrels

I'd like to ask our Damascus experts if they have come across any reference to the use of flux or any other methods that may have been used to prevent the formation of scale when the steel/iron was heated to forge welding temperatures.

This doesn't answer your question Keith, nor can I, but is an interesting discussion regarding damascus flaws, and does mention flux.

Shooting: Its Appliances; Practice; and Purpose
James Dalziel Dougall
Published by S. Low, Marston, Low, & Searle, 1875
http://books.google.com/books?id=-ToCAAAAQAAJ&pg=PA25&dq=damascus+barrels&lr=#PPA24,M1

There are various kinds of flaws in barrels, such as "cracks," "sand-holes," and what are technically termed "grays." The first two are comparatively rare, but the last is the great annoyance of the barrel-forger and gun- maker; and, in fact, may be said to exist more or less in all barrels. They are those little specks in the iron which may be seen more readily after a gun has been used, from the rust showing more upon them than upon the smoother surface. In themselves, unless very numerous, "grays" lead to no insecurity in the barrels, and are not real flaws ; but the freer barrels can be made from them the better, as, unless when kept clean and well-oiled, they may in course of a long time deteriorate the barrel. As a rule they cannot be detected while the work is in progress, and only make their appearance on the barrels being browned. Conversely, strange as it may appear, most frequently they become less apparent in course of time, and on the barrels requiring to be browned a second time, disappear altogether. The reason why the first browning causes them to appear is that the infinitesimal quantity of oil they contain neutralizes the chemicals, and the mark is then for the first time made visible. The reason why they eventually disappear is their extreme shallowness. The very finest of barrels may therefore, and often have been, rashly condemned by sportsmen for harmless spots which no foresight could prevent. Were they actual flaws, they would appear during the process of filing.

The "sand-hole" is a thorough flaw; and if the barrel stand the proof at all when it exists of any size, still it cannot be quite safe, as the hole will often run in a tortuous direction for a considerable length under the surface, being, as its name imports, full of fine sand, or probably of the powder used as a flux to promote complete adhesion in welding the barrel, which has adhered to the iron, and been closed upon in the act of forging. The Damascus barrels, in contradistinction to "laminated steel," I have always found in my experience the most free from "sand- holes." Indeed of late years I have not known an instance of this flaw, through using Damascus barrels in preference to all others. Many an annoying instance I had in the days when "laminated steel" was puffed up, and when, after a gun was nearly finished, a "sand-hole" would be discovered, into which I could insert a piece of fine flattened wire and pass it half-way round the barrel between the laminae.

The "crack" is the worst of all flaws. This is a separation of the fibres of the iron from overstraining of the twist; and consequently every discharge of the gun must, by the expansion of the metal, more or less widen the crack, until it run right round the barrel. The same "solution of continuity" may also exist from imperfect forging, and the same result takes place. The author has repeatedly taken old double barrels asunder, with a crack in one of them so lengthened through time that the barrel was nearly separated into two parts. When this crack runs round the barrel the danger of bursting is exceedingly remote; but should it have a longitudinal direction, or if there be two near to each other, the danger is much increased, and, sooner or later, the barrel will give way. The longitudinal crack almost never occurs; and all the varieties of Damascus barrels are the most free from this kind of flaw. A hole right through a barrel would be much more safe than any kind of crack; and, in point of fact, many barrels are safely used for years with a small hole right through them. A crack may at once be detected by suspending the barrels, and striking them with a piece of wood, when, if faulty, they will not emit the clear, ringing sound they otherwise do.

The outside of barrels should be well filed and polished. The smoother they are, they will remain the more free from rust, through the closing of the pores; and consequently they will last longer. The filing should also be regular, leaving no hollows, but retaining an equable strength, and allowing a regular expansion throughout the entire length when fired.

The inside should be as bright as a mirror, and free from flaws. Slight marks or rings, left by the boring bit, can hardly be avoided, and may be found in the best barrels; but there should be n& hole likely to retain dirt or damp of any kind, which can corrode the iron.

Since the introduction of breech-loaders these slight marks form a frequent subject of remark. The tube, being open, is glanced through, and the presence of such a mark is detected, whereas with a muzzle-loader this might never have occurred. Timid sportsmen fancy there is danger where none exists. In the first place, writing of course of these unavoidable marks only, no good gunsmith would permit any barrel with a real flaw to leave his hands. His final loss would be greater than his first. But besides that, in the tentative process of making a gun shoot well, he is bound by necessity to leave the barrel as it is the moment he has developed its shooting powers to a recognized standard. Hence he is debarred from polishing out any mark or discoloration for the mere sake of appearances. In breech-loaders the master-gunsmith enjoys the same opportunities to detect flaws as the sportsman, who may rest assured that the confidence put in the good faith and judgment of the former is not misplaced. The same minute marks existed in muzzle-loaders, and were known to do so by all gun-makers and by most experienced sportsmen, yet no one thought of challenging them; they were taken as a matter of course. The facility of looking through the barrels of breech-loaders has caused these utterly harmless marks of boring to be considered something new and improper. The spots are infinitesimal in size or depth, and are only visible through contrast with the bright polish of the general tube. The barrel never deteriorates with time through their presence.

Good barrels will often, when subjected to the same circumstances which would burst an inferior article, bulge, or swell out, like a glass tube heated at one part and blown into. When the bulge is not very large it may be partly hammered down, but no barrel so treated can be called truly safe, until subjected to a fresh "proof."

More here http://docs.google.com/Doc?id=dfg2hmx7_220dpc9nsck

Keith,

I have never seen evidence of borax or any other flux being used. Nor is there anything in the literature about fluxing. Having said that, it does not mean they did not do it.

There was a fixture on the side of the anvils in Belgium. They used it to scrape the red hot metal. It is unclear if they were scraping oxidation or using it for another reason.

Pete

I am very grateful for all of the responses to my query, especially yours Drew.
I think Bob Beach actually nailed it in regard to the "shallow rifling" in ther right barrel of a woodcock gun (which is the context in which I was first introduced to the term) and it certainly makes sense if you wanted the advantage of spreading your shot charge even wider than a cylinder bore would allow.
Again, thanks to all.

Dean

Thanks very much for that info. I've often wondered about that because I once worked as an electrician in a steel mill, and did a couple years time in the hot mill. I was amazed at the amount of scale that was generated on blooms or re-heated slabs. A lot of effort went into scale breaking and use of sprays to blast off the scale via the water instantly turning to steam just prior to rolling. Rolled in scale was considered an inclusion or flaw, and avoided at all cost. So it always seemed a contradiction that a Damascus barrel, which if unfluxed or protected by inert gas, could be expected to contain perhaps 8000 psi or more. But they do... don't they?

Keith,

A couple of thoughts. The basic ribbons came from a rolling mill, this is the case for Belgium, where they were rolled while red hot. At the forge, they were subjected to 150+ heatings. I have seen blacksmiths working. They often have a small specialized ladle and a bucket or at least of pile of borax sitting near by. Watching the documentary neither of these is present. Yes, they were expected to handle pressure. The proof process insured that they could indeed handle it.

I read an interesting article circa 1900. The author spoke about opening day "in the marsh" and the number of exploded guns both fluid and damascus that would result. I think many of the "mistakes" have long since ended up on the junk pile. See the article posted above about sand holes and cracks. We simply do not observe these defects today in any great number. The "grays" are a separate matter. The Belgians blamed that on the coke used in the smelting process. Their solution was to continue to use charcoal smelting for damascus barrels.

Pete

US Patent #9999 was the one I had in mind. Issued Sept 6, 1853 to Thomas Warner of Chicopee Mass. It describes twisting a "Solid Bar" & then boring to gauge.

The definition of the metal may actually depend on the time period and metal used. Pig iron, white, silvery, gray, blazed, glazed, etc., is high carbon cast iron that was formed in the blast furnace into pig like casts. Wrought Iron is iron with silicate, an intrinsic flux, and little carbon, which can be found in old bridge structures. In England it is termed malleable iron and is universally, usually produced via a puddling process, in a pasty state just short of being fluid which is due to to a lower tempature and possesses a small bit of slag and isn’t really hardened upon quenching. A rabbler mechanically stirred iron silicate and iron oxide into cast iron to yield malleable or wrought iron. Some of the iron silicate was pressed out later as muck bars and subsequent merchant bars were made. Bascially the only thing that differentiates steel from wrought iron is that of being, or have been in a fluid state, free of slag and containing less than 2.2% of carbon and from a practical standpoint it required to have less than 1.5% of carbon which is where it differs from cast iron.
Wrought steel is wrought iron that can be hardened by quenching.
Cement steel was formed by the cementation process of carburizing wrought iron, and less frequently low carbon steel.
Early German Steel was produced in a bloomery very similar to a Catalan forge and was the result of refining pig iron to a very similar state of wrought iron.
Flux could be acidic or basic with basic flux being raw limestone or lime as well as magnesia, dolomite and possibly a few others. Sand was considered to be an acid flux and it with borax, http://en.wikipedia.org/wiki/Borax , was used in welding to form a fused cinder. An acid open hearth process was rarely used vs. a basic open hearth process. So I would venture a guess that borax or lime was used as a flux and earlier silica may have been a default flux.

Kind Regards,

Raimey
rse

I haven't found the article, only a reference but Captain T.M. Bagnold in an address or letter to the Society of Arts circa 1851 notes that the Bombay tube makers attempting to make tubes from iron hoops from British casks would use a mixture of mud, clay and cow or horse dung to prevent oxidation or used as a flux. They also soaked the tube in vinegar or a sulphate of iron solution.

Kind Regards,

Raimey
rse