I suspect our confusion (other than the fumes and Corrosive Sublimate ) come from http://heuse.spahistoire.info/chinhotcanondamas.html

The illustrations clearly show the 'stars' to be black



Carried on in Sachse's "Damascus Steel"



When the finished product clearly has WHITE stars

W. W. Greener in "The Gun and It's Development" 1907 doesn't really address the contrast issue, and discusses both pattern welded and fluid steel browning
http://books.google.com/books?id=3HMCAAAAYAAJ&pg=PA270&source

The bronzed appearance of the finished gun barrel is obtained by a process of rusting the barrels, the rust being cultivated, then stopped; the complete oxidation of the surface renders the barrels less liable to rust by natural means.
The beautiful figure of the fine Damascus and laminated steel twist barrels is not surface-deep only; the figure runs completely through the barrel, as will be made clear by referring to the description of the process of making the iron for, and the methods of welding, the barrels. Consequently, it is impossible to get by browning any finer or more beautiful figure than is already in the barrel; it is possible, by inferior browning, to hide that figure, or so obscure it that recognition is barely possible. That fine gloss, seemingly the effect of lacquer or copal varnish, is nothing more than the highly-burnished surface of the barrel, which before browning was as highly polished as a silver mirror.
The colours which can be obtained vary from a light yellowish-brown, through various red-browns, to a deep Vandyck-brown. A rich plum brown is obtained if time is taken and a little black brimstone, say 1/4 oz., added to the above mixture. Spirits of nitre and nitric ether are sometimes used in lieu of spirits of wine.
The black-and-white brown may be obtained by using much diluted mixture, and touching up the barrel before boiling by sponging with water in which a little muriate of steel has been stirred. The colours can be heightened also by plunging the barrels in cold water immediately they are taken from the boiling trough. In all fine-figured barrels the coating of rust is necessarily very thin, or the figure could not be distinguished. This coating of brown soon wears off. The only remedy is to have a greater body of brown, hiding the figure, or to use the black-brown, as in military rifle barrels. This last brown is much more durable, and effectually protects the barrels from rusting by salt air, hence is much used on ducking, punt, and wild-fowling guns.
Steel shot barrels, when black-browned, show no tendency to rust, however much exposed to atmospheric changes. The black-brown is obtained in a shorter time, and a much stronger mixture may be used—as, for instance: 1 1/2 oz. spirits of wine; 1 1/2 oz. tincture of iron; 1 1/2 oz. corrosive sublimate; 1 1/2 oz. sweet spirits of nitre; 1 oz. sulphate of copper; 3/4 oz. strong nitric acid; 1 quart of water.
Before re-browning any figured barrel it is essential that the old brown be effectually removed. The barrel must be well polished again before re-browning, if that fine sheen so much desired is required; otherwise, simply rubbing off the brown with emery cloth, with fine emery in water, or by sponging the barrel with strong vinegar, will answer the purpose.

Another example from a photomicrograph as part of the metallurgical study METL performed on the burst Remington barrel. 20X 3% Nitrol etched steel is grey-black, iron silver-white; at least that is what the gin-u-wine metallurgist told me

Finally, I'm still looking for the specific quote, but Dr Gaddy said so

The color of the barrels after etching CAN be manipulated by the browning solution and also the alloys in the metals. Steel with a manganese content (10XX Carbon Steel) will typically etch black. Nickel will produce silver, and chromium gray. And from the limited composition analysis study it appears at least by the 1890s quality steel barrels were at least 1020 advancing to 1030 & 1040 Carbon steel, sometimes rephosphorized.

Drew, in the first post there appears to be three materials in "Carried on in Sachse's "Damascus Steel"
Is that your take ?

I think this comment may be significant. It looks like for differences in color to appear, the barrel surface needs to start off uniform. It's been mentioned that some of the barrel finishes don't just stain or color a component, but physically alter the surface roughness, for lack of a better term, differently for the different components.

While it may not be applicable at all, if you'd like to look at knife making examples, maybe look at wrought iron san mai. It's just a forge welded external layer of wrought laminated on the sides of a blade. Anyway, the wrought, not the modern carbon steel core/cutting edge, would likely be of the era from around when some of these barrels were made. On many of them, you can see how differently the wrought iron finishes based on differing grit of finish from rough forged to high polish on the same piece.

I think a meaningful difference could be that the stringy look of wrought iron that can show, might be significantly reduced by the heavy drawing process that it looks like the barrel makers did on most every step of the way. Always interesting stuff Doc Drew, and I appreciate your historical research.

Amazing they had this figured out by the 1600s. Four Iron Crolle Miquelet barrel reported to have been found during excavation of a dump site in Germany



BTW: the Hohokam decorated shells by etching them with citrus juices.

"From Art To Science. Seventy-Two Objects Illustrating the Nature of Discovery" Cyril Stanley Smith
p. 15
The etching of surfaces by the application of corrosive substances to produce decorative effects, a deliberate mode of “weathering,” was practiced as long ago as the third millennium B.C. in India...Perfected in the armorer’s art in Europe, the technique of etching was more pacifically applied by the American Indians of the Hohokam culture, who used acid fruit juices stopped by natural resins to decorate seashells.

Interesting stuff
https://docs.google.com/document/d/1me32b1AZQqr361CVtb-jeAoK1hDO2ZT6QR1fXQkjY0c/edit

The Journal of the Iron and Steel Institute
London, 1889
http://books.google.com/books?id=6xoAAAAAMAAJ&pg=RA1-PA353&dq=
Damascus Steel p. 353
According to Demmin, the treatment of steel known as "damaskeening" is no longer practised at Damascus. The metal used is a cast steel, in which a strongly marked figuration is produced by the presence of crystallised graphite, which is rendered evident by the corrosive action of acids. In 1804 Clouth imitated the oriental Damascus steel, and Stodart and Faraday considerably improved the process of manufacture. At the present time artificial polished Damascus steel is largely made in France, whence it is exported to the East. It is also made for gun barrels at Liege, and for swords at Solingen and Passau. There are black, brown, and yellow damaskeenings, which are produced in the following manner: Several bars of steel of different hardness, or of iron, cast steel, and steel, are welded together, hardened, and formed into blades. They are then treated with acids, where by the harder portions acquire a dark colour, whilst the softer portions remain bright.
The figurations appear wavy, striped, or mosaic-like, according to the manner in which the various bars were hammered together. The finest and most expensive variety is said to be the Liege Renard (possibly Bernard) damaskeening, which is formed of three bars welded together, each of which consists of seventy-two iron and seventy-two steel wires. The gun barrel is formed by smithing this compound bar, which is wound round an iron cylinder placed over a mandril. When finished, the iron cylinder is drilled out.

This should be confirmation of hardness = darkness FOR NON-ALLOY steel

Rockwell Hardness
Grey Cast Iron - 63
Wrought Iron - 65
AISI 1020 - 68
AISI 1030 - 80
AISI 1040 - 93

Brinell
Grey Cast Iron - 100
Wrought Iron
1020 - 121
1030 - 149
1040 - 201

Hi Doc Drew, just an observation, could you check which Rockwell scale was used for those numbers. Sometimes the C scale is used for steels and that might make those numbers seem high.

Back when you ran the metallurgy studies, I think you came up with an average carbon content of around/under .1%. Just a guess, but that might put the hardness numbers of 1010, or up to 1020, very close to the hardness number for wrought iron.

Based on the analysis that you had done for overall carbon percentage, and reasonably counting on carbon migration, chances are that nothing near 1030 or 1040 was widely used in the damascus that you had tested. Just wondering out loud is all. Thanks again.

"there appears to be three materials"

Another illustration Daryl with what appears to be only two materials, and I've never seen a description of using alternees of different forms of Wrought Iron and Decarbonized or Carbon Steel in the same rod

Thanks, Drew. I am convinced.

SRH

Youz guys are making me give up all my good stuff Hope no one is reading this!

The chemical composition of the post-1900 Remington 1894 A grade with "Oxford 2 S.J." 2 Iron Crolle was similar to AISI 1005 low alloy steel by Optical Emission Spectroscopy (OES).

SO, as Craig astutely observed, the iron was (surely) wrought iron and the steel was likely low carbon "mild" steel with less than .2% carbon. AISI 1020 has a tensile strength of 55,000 - 60,000 psi.
AISI 1010 is 47,000; about what the Pattern Welded barrels measured in my study.

Drew,
Thanks for all of your research and posting of information in this thread. It is all good information and useful to this discussion.

Bear with me as I take the time to compose a rather lengthy response. This topic is about to get deep.

I left by Red Ball boots back in KS brother, but still have my 14" L.L. Beans

Drew, I pray that your mind will want to wade through my information barefoot. LOL!!

The comments about hardened steel etching darker, is a common topic in discussions between knifemakers. However, we first need to examine the damascus finishing techniques of knifemakers and understand how they are different from the processes used to finish damascus gun barrels.

Modern knifemakers typically use ferric chloride to etch their knife blades. Most often, the source of the ferric chloride is Radio Shack printed circuit board etchant solution. The Radio Shack solution is usually mixed one part etchant solution to three parts water. A fairly strong mix. After the damascus knife blade is sanded to around an 800 to 1000 grit finish, it is placed in the ferric chloride solution.

The purpose of this etching process is twofold. For one, it develops the dark coloring of the steel, as Drew has mentioned. Secondly, it creates topography on the surface of the steel, with one of the steels being etched more deeply than the other steel. A common combination of steels that knifemakers use to make damascus are, 1084 high carbon steel and 15N20 tool steel. 15N20 is almost identical to 1084 steel, with the exception of having 2 percent nickel added to it. The nickel acts as a resist to the etchant solution. So, the layers of 1084 are eroded much more quickly than the layers of 15N20. The result is a surface on the knife blade that has a lot of topography; or hills and valleys. Knife blades are often etched so deeply that the topography can be felt with a fingernail.

The darkened coloration that Drew has mentioned, is corroded steel. The total amount of time that a knife blade will spend in this strong ferric chloride etchant solution ranges from around 10 to 30 minutes. A knifemaker typically has to remove the blade from the etchant solution occasionally to card away some of the corroded steel, as it becomes a passivation layer, slowing the etching process. The corroded steel, which is the dark coloration mentioned previously, is often referred to by knifemakers as “oxides”. I am not certain that this material is actually an oxide, by the proper chemistry definition. As its’ formation is the result of a chemical reaction, I think it could be a separate product of the ferric chloride and the steel. Need a chemist to balance this chemical reaction equation to find out for sure. But, what if something other than ferric chloride was used for etching? Copper sulfate, sulfuric acid, hydrochloric acid, nitric acid; what then is created? What color will it be? I can tell you from experience, that damascus steel etched with hydrochloric acid does not develop the same dark coloration as does steel etched with ferric chloride.

Whatever this darkened, corroded steel material is, knifemakers often use it to display the damascus pattern in their knife blades. This material is not very durable and is fairly easily damaged. That is why knifemakers etch their blades so deeply. After the etching process is completed, the knifemaker carefully sands the blade, polishing the tops of the topography and leaving the darkened material in the valleys. As this darkened material is not very durable, many knifemakers have taken to scrubbing it away and then chemically darkening the blade with other chemicals; bluing, parkerizing, etc. The blade is then carefully sanded, leaving the newly darkened areas in the valleys.

The discussions among knifemakers as to what color different steels will become during etching, surrounds the use of the corroded steel material, whatever it is, to display the pattern in their damascus blades. Their obvious concern, is creating a dark material that will result in significant contrast in the damascus pattern. For those who remove this material and darken the valleys in the damascus with another coloring method, the coloring of this material darkened by the etching process is irrelevant.

I have heard in many knifemaker’s conversations and also seen posted in knifemaker forums (such as the one that Drew linked in the Vintage Barrel Composition thread), talk about what alloys in steel create a darker etch. Many have eagerly proselytized the “factoid” that high manganese content in the steel creates a darker etch. I don’t know where this idea came from. I expect that some “expert” said it to be so. I’ve never heard who this expert was. But, many are willing to spread a concept that they have not personally tested for themselves. On the face of this statement, the suggestion is that the manganese somehow changes the chemical structure of the darkened, corroded steel material. I’ve not heard anyone proclaiming this so called fact, explain the chemistry of how that would happen. I will later return to this subject.

Now, on to contrasting the process for finishing damascus gun barrels to the process commonly used for knife blades. I have never finished a damascus gun barrel with the methods commonly used for this purpose. I have however, blackened steel barrels by the slow rust method. Having read many descriptions of methods used to finish damascus barrels and the experience that I have had with slow rust bluing, I think I understand the damascus barrel finishing process. If I state anything incorrectly about the process, PLEASE correct my inaccuracies. Thank you.

Finishing damascus gun barrels is typically done with much weaker etchants and acids than are used to finish damascus knife blades. Rather than significantly destroying steel to display the damascus pattern, the damascus barrel finishing process seeks to generate and cultivate an iron oxide layer on the surface of the barrel. Some do a mild pre-rusting etch on the barrel with a weak solution of copper sulfate or ferric chloride. I assume that this is done to create a small degree of topography, to facilitate carding away some of the coloring on the damascus layers that stand proud of the other, more etched away layers. Next, a mild acid solution is applied to initiate rusting and then allowing the barrel to rest in a humid environment to generate an even layer of red iron oxide (Fe2O3). If the finish is to be black and white, the barrel is boiled in water, with perhaps some chemicals added to deepen the black. The boiling process converts the red iron oxide (Fe2O3), into black iron oxide (Fe3O4). The rusting carding and boiling process is repeated until a sufficient layer of iron oxide is developed for an even finish. Occasionally, the barrel may be subjected to a quick etch in copper sulfate or ferric chloride during the rust finishing process. This etch loosens the rust finish on the layers of damascus that are not so deeply affected by the rusting process, allowing the rust finish to be manually removed from these layers in a less aggressive manner; thus protecting the rust finish on the other layers in the damascus pattern.

Reasonably accurate description of damascus barrel finishing??

To recap; damascus knife blade finishing uses strong etchant solutions to deeply etch selective layers in the damascus pattern. This etching process creates a dark, corroded steel/chemical compound, which is probably not an actual oxide. This darkened material is often used to create contrast in the damascus pattern. Damascus blade finishing is fast and harsh. It is typified by destructive corrosion of steel. Damascus barrel finishing is a delicate process, using mild etchants to develop an iron oxide layer on the surface of the barrel. Both manual and chemical methods are employed to gently remove coloration from the damascus layers that have been least affected by the coloring process.

Now to discuss what is similar between damascus knife blade finishing and damascus barrel finishing. Both finishing processes rely on electro chemical corrosion, to either etch or rust the ferrous materials of the blade or barrel. Electro chemical corrosion of ferrous materials is easily researched on the internet. However most information concerns how to prevent corrosion, rather than how to utilize it for artistic embellishment. But an understanding of the reaction involved in electro chemical corrosion, plus the metallurgical knowledge of steel grain structure, will provide answers to the questions of what ferrous materials react to electro chemical corrosion faster and perhaps also darker.

To be continued…………

I forgot to pose this question as food for thought.

In a visual examination of damascus barrels, what percentages do you see between the colored material brown/black and the white material?

From Greener’s “The Gun and Its Development”
The old fashioned laminated steel was composed of nearly three parts of steel; best English damascus and modern laminate steel contains over 60 percent of steel; and the best silver-steel damascus contains nearly 75 percent of the best worked steel.

(From another paragraph): By using more iron than steel, and keeping to the same arrangement of the metals, a very inferior barrel would result.

Thanks brother. Still tip toesieing

c. 1860 "Old fashioned" laminated steel - maybe 1/2 & 1/2?



Greener's "Silver Steel" laminated steel - much more steel



Probably c. 1890 "English machine-forged 3 rod Laminated steel" which was the winner of Phase I of the Birmingham Proof House Trial; browned so the contrast is obviously different



VERY interesting Lefever Optimus with 1890s Laminated Steel

Re: manganese

The knife fella may be referring to AISI 13XX "Manganese Steel" or AISI 15XX Carbon Steels

Both 1330 (.30% Carbon) and 1340 (.40% Carbon) allow 1.6 - 1.9% manganese.

AISI 1525 allows .8 - 1.1% and 1551 .85 - 1.15%

AISI 1020 Carbon Steel allows .3 - .6% manganese. 1030 and 1040 both allow .6 - .9%.
http://www.blueshield.ca/en/docs/pdf/techinfo/databook/e-fsection218to228.pdf

And to clarify, it is my opinion based on only two crolle damascus barrels that both showed very low carbon % by OES that the iron was no doubt wrought iron and the steel either Decarbonized (carbon .06 - .1%) or low carbon low alloy - possibly AISI 1010 which Siemens was likely making in the 1870s.

I didn’t mean for my earlier comments to sound too harsh, concerning my knifemaking brethren. They are serious crafters, earnestly seeking information on how to make the best and most beautiful blades possible. Their sincere desire for knowledge can leave them all too willing to accept information at face value, rather than questioning why.

The knife fella may be referring to AISI 13XX "Manganese Steel" or AISI 15XX Carbon Steels

I know the knifemaker discussions about high manganese steels etching darker, did not include the 1300 or 1500 series of steels. The considerations were most often between the use of 1095 and 1084 steels, in making damascus steel. Below is a link to one of these discussions.

Knifemaker Discussion

Electrochemical Corrosion of Steel:
Electrochemical Corrosion

The etching of steel is an electro chemical reaction. The etchant solution acts like countless microscopic batteries, which attach to the metal surface and conduct an electron exchange with the metal. The attachment points for these microscopic batteries, are the metal’s grain boundaries. The more numerous the grain boundaries, the more nucleation points for the chemical reaction. Steel with a finer grain structure, will etch much more quickly than a steel with larger grain structure.

As manganese promotes hardenability and fine grain structure, it is not surprising that steel with a high manganese content has the potential to etch darker. However it is not the manganese itself that affects the etch, it is simply the fine grain structure of the steel. If a steel with low manganese and a high manganese steel are heat treated to have the same grain structure, both would etch similarly.

In regards to harder steel etching darker than soft steel, it is not the Rockwell numbers that cause the difference. It is the fact that hardened steel has a finer grain structure than unhardened steel.

Sorry for being slow to continue this thread. It took me a few days to put some more information together.



Here is another reference, agreeing that chemical corrosion propagates from ferrous grain boundaries. This, from a document on the use of etching solutions to prepare samples for metallurgical testing.

National Board of Boiler Inspectors - Grain Boundaries

ETCHING:
In order to observe the microstructure, a piece of the metal is smoothly polished to a plane and mirror-like finish. The prepared surface is chemically attacked with dilute acid for a short period, a process called "etching." The grain-boundary atoms are more easily and rapidly dissolved or "corroded" than the atoms within the grains. A small groove is left at the grain boundaries. Since a groove will not reflect light as do the flat, polished grains; the grain boundaries appear as black lines, and the structural details are visible.



So to review; in finishing of damascus steel, the goal is to create a bold display of the damascus pattern. Knifemakers use destructive electro chemical corrosion to create deep etching and topography between the layers. Damascus gun barrel finishing, typically uses weaker etchant and acid solutions to create only a small amount of topography and gently develop the light vs. dark coloring to display the damascus pattern. BOTH, finishing processes, utilize electro chemical corrosion reactions to achieve the finish on the surface of the material.

Steel is the ferrous material in damascus that is very reactive to the etchant solution. As corrosion propagates at the grain boundaries, more active corrosion is facilitated by a ferrous material with a small grain structure. The carbon in steel also tends to precipitate into the grain boundaries, as cementite. The particles of cementite in the grain boundaries, provide more anodic connections for the electro chemical corrosion reaction. Steel being very reactive to corrosion, will create the colored (brown/black) layers in the damascus pattern.

The other layers in the damaacus pattern need to be of a light color. There are two ways to accomplish this. Simply use a ferrous material that has a larger and less dense grain structure. Or, use a ferrous material that has alloys that resist corrosion. As noted in the earlier comment about the steels that knifemakers use for damascus steel, 15N20 steel, with a corrosion resistant 2 percent nickel content is laminated with the much more reactive 1084 steel.

Damascus steel gun barrels have wrought iron, as one of the ferrous materials used. Wrought iron lacks the alloys necessary to create fine grain structure and it also lacks enough carbon to precipitate out of the ferrous grains to create a high number of anodic connections to facilitate electro chemical corrosion. But more importantly it contains silica, which acts as a resist to the etchant solution, inhibiting the effects of electro chemical corrosion.

Artmetal.com - Wrought Iron

The slag in wrought iron also provides natural corrosion resistance. Let's face it, nearly all ferrous metals rust, but wrought iron does a better job at handling it. As corrosion progresses, the fibers tend to disperse the rust into an even film, which gives the metal a natural brownish appearance. This film repels the scattering spotty corrosive attack t that other metals endure.
Because of its corrosion resistance, wrought was the metal of choice in earlier years for marine use, bridges, and girders. In fact, in extremely corrosive areas, an architect may still specify the metal.

Real Wrought Iron Company

The important corrosion properties of wrought iron are therefore due to its impurities in the form of slag. It follows that iron and steel without the slag will not exhibit the same corrosion resistance, and this is what is found in practise. Furthermore the slag has additional advantageous in relation to traditional forging techniques, especially fire welding.



So finally…

My THEORY is that the wrought iron layers of gun barrel damascus are always white. Because wrought iron is resistant to the electro chemical corrosion process. The steel layers are always the layers that bear the color (brown/black). Because the grain structure and carbon content of steel promote the electro chemical corrosion reaction.

I would really like to hear from the guys who finish damascus gun barrels. Which material do you perceive etches light and dark? Do you do your finish work with a plan to turn either the wrought iron or the steel dark? Are you able to reverse the colors on the barrel by changing your process?

As always thank you Steve.
This is a 25X 10% Nitrol etched section clearly showing the grain structure of the darker stained steel. The black globules are mostly silica, and the metallurgist thought they "stretched" in the weaker iron component in response to the shearing forces at the time of the burst

Interesting picture Doc Drew.

By 'stretched' are you looking at the roughly 45* dark streaks in the light colored band? Maybe I'm seeing it wrong, but that may not be signs of the burst as it does not seem to cross into the dark colored band. Also, those specs you showed earlier had a very similar strength of wrought and low carbon steel. Again, I'm probably seeing it wrong.

Also, maybe of note, if that is a depiction of steel grain in the darker colored band, it seems that the nitol etch is darkening more than just the grain boundries.

Back a few years ago, was there the conclusion that the dark globules might have been carbon? Just wondering.

Thanks for the topic guys.

Craig: I only play a metallurgist on DoubleGun The "stretching" may have also occurred during the rolling, twisting and hammer welding of the rod.

Re: tensile strength
AISI 1005 Low Alloy Steel: 40,000 psi
AISI 1010 Low Carbon Steel: 53,000
Wrought Iron: 34,000 - 63,000 psi; average 52,000 psi
Siemens (Open Hearth) Low Carbon Steel: 55,000 - 62,700 psi
Bessemer or Decarbonized Steel: average of 63,000 psi

BUT Yield Strength for Wrought Iron is 23,000 - 32,000; Bessemer 33,000; 1010 44,200.

The "wrinkles" are plastic deformation (stretching) before ultimate strength is reaching and the barrel bursts



This is a 500X SEM of an inclusion which was predominantly silica with phosphorus and sulfur ie. slag.

I am certainly no expert at examining micrographs, but I understand that it is an exceptionally challenging thing draw conclusions from. Must take a lot of experience to understand what is being viewed.

I know that metallurgists have always had difficulty with measuring grain size in a polished and etched sample. The sample only allows viewing the 3 dimensional grain on a single plain. It’s sort of like sawing through a block of frozen soup and trying to determine the size of the pieces of vegetables by looking at what has been revealed in that single view. You don’t know what has been removed by slicing through the sample and you don’t know what lies below the viewed surface.

Drew is correct that the silica stretching may have occurred during any part of the mechanical distortion of the wrought iron material. It could go all the way back to the shingling process to make the wrought iron.

It seems to me that making a determination of what happened to a piece of steel by looking at a micrograph, is like trying to describe all of history by looking at a single snap-shot in time.

I've used several processes, the iron always stains white. In my previous post about how the layers were arranged in the billet determining what color the spiral riband edge weld was/is based on a comparison between regular Damascus and three-iron Washington, Where the weld stains dark.

Regards
Ken

Thanks guys.

What I was thinking, was that the silica/slag stretching seemed to be what typical wrought iron might look like, and likely the dark/light difference goes to some deeper level than 25x. To me, the various micrographs that Doc Drew has shown, seems to show that potential weak spots, inclusions, are managed. Thanks for your time folks.

OKOKOK. I hope no pirate is reading this or my whole article might be "borrowed"

During the tensile testing at METL, it just so happened that a Twist barrel segment was machined right where a flaw was visible on eyeball inspection of the fracture surface. The inclusions are likely slag (silicates, phosphorus, sulfur and metal oxides) based on the appearance and Energy Dispersive X-ray Spectroscopy (EDX) spectrum. And I have a picture but ain't showin' it but will show this one

1895 Ithaca Crass with damascus barrels that were being cleaned up for reblueing. Initially just a small pit on the surface of the barrels, quickly grew into what you see here as polishing continued. Inside the barrels are bright and smooth, giving no indication of the large inclusion. Courtesy of Robert Rambler.

And the plot thickens regarding a distinct boundary between the wrought iron and "mild steel" alternees.
From METL's metallurgical study:

"The microstructure was banded, but there were not clear “iron” and “steel” microstructures. The overall material appeared to be a single piece of metal with segregations of inclusions. It is likely that the manufacturing process had combined the two original “iron” and “steel” materials into a more homogenous structure, but that without melting the combination was restricted to mechanical mixing and possibly diffusion.
The banded regions are likely predominantly comprised of the original chemical compositions, but during manufacture experienced changes."

Thanks much Doc Drew. Back to your 25x micrograph, there is the appearance that the body of the darker etching material and the body of the lighter material are fairly uniform. The grain seems to have the appearance of significant heat affect where the forge weld joins the two.

Looking forward to the article. Hope you etched that Ithaca Crass defect. I'd guess that was at a major weld failure, a manufacturing defect, rather than a material inclusion.

Practical Hints on Shooting, K. Paul Trench, 1887, “Barrels”
https://books.google.com/books?id=xrwUAAAAYAAJ&pg=PA20&lpg
Pour a drop of nitric acid of 1.2 specific gravity on the barrel, and allow it to remain there for a few seconds; then wipe it off with a piece of chamois-leather. On iron this leaves a light-grey spot, but on steel a much darker one—almost black.

And yet just a few paragraphs later, the author makes a contradictory statement. It seems that “somber hue” is meant to indicate a dark coloration. No wonder there is so much confusion on this subject.


The wavy water-lines so much admired in Damascus originate from the twisted metal, and are brought out by immersing the tubes in dilute acids, the corrosive action of which, operating differently on the iron and steel, causes the former to become of a somber hue, and the latter almost white.

Ya' think the English were just messin' with us

W.W. Greener "Manufacture of Iron for Gun Barrels"
http://books.google.com/books?id=LAsAAAAAQAAJ
"It is the twisting of the different metals that gives the various figures in the finished barrel. The steel being hard resists the acids, and retains a white or light brown hue, whilst the iron, or softer metal, is so acted upon by the acid as to be changed into a dark brown or black colour."

I’ve found that it is wise to take most old writings with a grain of salt. Not just the Brit’s. It seems that many early authors were not so much interested in being correct, as they were in making sure that no one challenged their assertions. The typical methodology was to make a statement of “fact”, declare yourself to be the supreme expert on the subject and then dare anyone else to say you were wrong. Sort of like being the biggest literary bully on the block.

I typically look for other knowledgeable contemporary authors to corroborate a statement made by one. Then this mutually agreed upon “fact”, must be weighed against what we know to be the scientific and metallurgical knowledge of the time. Just because several old authors agree on a subject, does not make it so. Case in point; the concept that cold hammering of steel will make it more dense.

"seems that many early authors were not so much interested in being correct, as they were in making sure that no one challenged their assertions. The typical methodology was to make a statement of “fact”, declare yourself to be the supreme expert on the subject and then dare anyone else to say you were wrong. Sort of like being the biggest literary bully on the block."


I'm sure glad we've all moved beyond that!!

Sounds as though the jury is still out on the question of whether it is the iron or the steel that ends up white after rusting and etching. There are still totally conflicting views on the matter, and I imagine that isn't going to change any time soon. Much of what has been written will be taken as gospel for decades even if it is incorrect, just as the idea that Damascus barrels are all ticking time-bombs one shell away from becoming a deadly grenade.

In the recent Composite Barrel thread, I was of the opinion that the only way to settle this would be to rust, boil, card, and etch samples of steel and wrought iron to actually see which material was most resistant to a ferric chloride etch, and which one had the staining most easily removed by the same ferric chloride etch. So the question for me at least is where to get some small pieces of wrought iron that are consistent with what nineteenth century Damascus barrel makers used. I'm assuming any relatively low carbon steel would suffice for the steel samples. I can get horseshoe nails at the local tack shop, but I have no way of knowing if they are made of wrought iron or steel. Then there is the question Steve Culver raised about different rusting processes giving different results after the etch.



I note that Steve wrote "THEORY" in capital letters, and I agree with him that the iron ends up white. In my limited experience with rust bluing and browning, the entire barrel seems to rust or stain relatively equally and evenly if I have done a good job of prep, and it is only after etching and carding that contrast between the iron and steel of Damascus becomes readily apparent. I've always assumed then that one or the other was simply more susceptible to having the staining or rusting oxide removed by the ferric chloride. And I've always assumed that is was the iron portion that ends up white if the etch is performed properly. But assuming or perceiving doesn't give us a definitive answer as to which material ends up white. I suppose a metallurgist could take a sample of finished barrel and tell us which part was the iron and which was the steel. I suppose it may not really matter as long as we get our contrast and bring out those attractive patterns, but it would be nice to know for sure.

We know that a "too concentrated" etch or a "too long" etch can remove all color and actually begin to eat the surface to the point where it can be seen and felt on the barrels, and this is also why we coat or plug the bores to protect the bare metal from the etch. I have stuck with very short etch times in a horizontal trough to minimize the chance of removing all of the color that I worked hard to get. But then, I never noticed that the weld boundary can end up either white or dark, and have no good explanation of why that would happen. As some food for thought, I'll toss out the idea that the final color of the weld joints could have more to do with the actual weld process, i.e., temperature, flux (if used), amount of scale formation, etc. than it has to do with the chemicals used in the rusting process. That's just a theory with absolutely zero facts to support it.

Keith, real wrought iron is available, but it's not likely to be sold in the form of a modern manufactured item. It's not so hard to find, reclaimed raw bar stock, most likely from an old bridge or building tear down, or maybe 1800's maritime chain links. There's a shade tree test that works pretty decent, make a partial cut in a bar, then try to break it with a sharp 90* hammer hit. Wrought will tend to show characteristic stringing.

I think antique wrought would be a decent example of what might be in a gun barrel. I'd have my doubts if a true simple steel was readily available to simulate what might have been around back when. Steve may have some wrought in his shop, and I wouldn't be surprised if he might not have tried an etch or two. While a too long etch on a barrel would not be a good idea, it may just be an exaggerated example of the differences in materials that it takes to show a color difference.

I have some wrought iron in my shop and of course a good selection of steels. I should be able to source any type of steel that I don’t have, through my suppliers. I would be happy to provide wrought iron and steel samples for testing. But rather than test the iron and steel separately, it may be better to have them made up into damascus. I could easily make some. I believe the test would be more accurate, if the two materials were welded together and subjected to testing simultaneously, rather than separately. Seconds matter in the finishing process. Treating them separately, could result in errors.

I’m thinking a low layer count (maybe 11 layers) forge welded, twisted and then flattened out into bar stock. I could forge the welded rod to around 1 inch square before twisting, rather than the approximately 3/8 inch that was used in gun barrels. The larger stock and broader damascus pattern would make identifying the iron and steel layers easier.

This issue with this plan, is whether the alloy content of the iron and steel that I use, matches the materials used in gun barrels. We have no good records of what the Belgians used. I have wondered if there were any records left of British production. I sent an email to Graham Greener a few years ago, asking if there were any old records from Greener’s damascus manufacturing. He never responded to me. Maybe someone here has a significant enough presence to get Graham’s attention and secure a response from him?

As far as the wrought iron, I have some anchor chain and wagon tire material. I suspect that the silica content of the anchor chain and wagon tire iron is higher than would be used for gun barrels. Though, I have not a clue. I can restack and weld the iron to reduce the silica content; same as was done in the piling process of long ago. But, I have no idea what I am shooting for in the final product and not sure of a method for testing the material for silica content.

The steel is a similar issue. What was the alloy content of gun barrel steel and what modern steel approximates that alloying?? Drew had some barrel steel tested. But, is that one sample fully representative of the gun barrel industry? It’s hard to argue against test results, but I found it quite surprising that the steel in the barrel was determined to be of very low carbon content. I expected that the barrel manufacturers would have used steel in the .4 to .7 carbon range. Perhaps I am totally wrong, but this is the reason why I am concerned that one testing result may not be completely representative of the industry.

There is one other possibility for analyzing this question. Perhaps I just need to go look at a bunch of damascus barrels. I have a rough barrel tube, which I purchased from Peter Dyson. I did a light etch on the tube with ferric chloride. This I did by simply using a rag to wipe a fairly strong solution of FC on the tube. The steel quickly turned dark, while the iron remained white. Certainly, this etch is not truly representative of the rust and etch process. But after etching, I used a small battery powered magnifier to examine the tube. It was very easy for me to tell the iron from the steel, by their different grain structure. There is a gun shop in Olathe, KS, which typically has about 100 damascus barreled guns in inventory. Maybe I just need to get myself over to Olathe with my little magnifier, and examine a bunch of guns to see if I can identify the iron and steel layers and their coloration.

Weld lines…… Yet another quandary.
I have a variety of suppositions on this topic, but no solid evidence to support my thoughts. I’m not going to share my musings, lest I just confuse everyone. The necessary information will be found at the molecular level. I know of no in depth analysis having ever been done on forge weld lines. But, I know exactly the guy to ask. He has the expertise and the equipment to do the testing. But, he is very busy and often takes a while to respond. I’ll yank his chain and see if he can help.

Only thoughts Steve. Instead of flattening the twist into a bar, a barrel might have more likely been ground to shape. A forged bar might end up with spots of long thin tapered laps of the two materials, where you may be looking for slices somewhere in the middle.

I've also noticed when wrought is heavily etched, the stringy appearance is easy to see. Doc Drew's pictures show tiny islands of slag pretty evenly distributed. I've always suspected that is the reason and result of the heavy drawing to produce a barrel, distribute and mitigate inclusions or defects.

Correct!!

I would flatten the rod to a thickness that allows for stock removal to develop the damascus pattern. The other option, would be to flip the flat layers 90 degrees and create a bar that just has long straight lines of alternating iron and steel. Maybe weld the 1 layer stack a second time, to create 22 layers. If the bar was finished to 1 ½ inches wide, the layers would be .068 thou in width. If the bar was 2 inches wide, the layers would be .091 thou wide. The possibilities are endless.

Principe de Fabrication d'un Canon de Damas Localité de la commune de Pepinster (Province de Liege) Belgique
The action of vitriol (Blue Vitriol = Alum and copper sulfate) brings out the steel in black and the iron in white wonderful patterns that repeat at every turn.

It is for threads like this that I keep coming back to read and reread to better understand

Also from Principe de Fabrication d'un Canon de Damas and not the best illustration but it does appear that Acier (steel) is black and Fer (iron) white



Masse - Lopin
Baguettes - Rods
Torsion - Twisting the rods
Ruban - Ribband
Enroulement - Wrapping the ribband around the broche/mandril
Forgeage - Hammer welding

Any educated opinions as to which alternee is steel and which iron? I'm thinking the blue-grey is steel and brown-grey iron?

Hmmm,

If Fluid Steel barrels of the period color black, why wouldn't the steel layers of Pattern-Welded barrels do also? Yes, it was a rhetorical question.

I should have 'splained that better

This is the Damascus Demonstration Rod, and I believe PRE-coloring



End view of the demonstration 'lopin' shown in my previous post



I guess the question is directed toward those who have worked with 'raw' wrought iron and low carbon steel

My thoughts; based on observations from my work.....

Hot rolled steel always has a bluish mill scale on it. So, I would assume the blue-gray layers are steel. The wrought iron having a silica content, may inhibit formation of mill scale. Thus, the simple red rust surface on it.

As someone who makes a lot of damascus steel, it is most common to place the low carbon element on the outer layers of the billet. The outer layers come to heat the quickest and will be at a temperature that can burn out carbon for a longer period of time. High carbon materials are placed inside the billet, where they are protected from the deoxidizing atmosphere in the forge.

I have raw wrought iron in my shop. I am willing to send a piece to anyone who wishes to test finishing of it. And/or, I will weld up a sample of wrought iron and steel damascus for testing. The only question will be whether the samples that I provide will be representative of the materials used in damascus barrels. I have some 1002 steel in my shop. It may be close to what was used in barrels.

Thank you Steve.

"1002 steel may be close to what was used in barrels."

I agree

The chemical composition of only TWO samples of pre-1900 2 Iron Crolle was similar to AISI 1005 low carbon, low alloy steel based on Optical Emission Spectroscopy (OES).

Wrought Iron may have .05% - .25% carbon.

Interesting about Steve's comment of the Silica content in Wrought Iron. One thing I've noticed is that during an agressive etch small inclusions in the WR actually appear to "Sparkle". I'm wondering if that is the Silica.

Sure, I'd volunteer for finishing the test pieces. I'll be starting another run in a few weeks.

Regards
Ken

Courtesy of Doug Miller
"Wrought iron when browned, leaves a distinctive pattern of longitudinal irregular shiny streaks presumably of iron silicate."

c. 1780 Wrought iron flintlock barrel



TAKE PICTURES KEN!

William Siemens set up the “Sample Steelworks” to develop the Siemens-Martin “Open Hearth” process in 1865, and his steel was in general industrial use by 1875. I've not been able to find any period composition analysis but very much suspect early Seimens steel was low alloy, low carbon; ?1002-1005 and very likely the steel component of Damascus.

P. Webley & Son began using Siemens steel barrels about 1880 and reported excellent results.
John Henry Walsh, The Modern Sportsman's Gun and Rifle: Including Game and Wildfowl Guns, Sporting and Match Rifles, and Revolvers, Volume 1, 1882
“Siemen’s Steel for Gun Barrels”
http://books.google.com/books?id=OLwUAAAAYAAJ&pg=PA445&vq
A 13 bore Siemens barrel did not bulge until 19 1/4 Dram Black Powder with a 1 1/4 oz. ball. Siemens then reported a tensile strength of 55,000 - 60,000. That would be similar to AISI 1010.

By one report pre-WWI Siemens may have been similar to AISI 1021 - 1034 Carbon Steels; The Sampling and Chemical Analysis of Iron and Steel, 1915
Oswald Bauer, Eugen Deiss, William Thomas Hall, p. 88.
http://books.google.com/books?id=03w6AAAAMAAJ&dq

Buturlin cited studies conducted at TOZ (Tula Arms Plant) likely immediately before WWI listing Russian Siemens-Martin tensile strength as 85,300 – 92,400 psi so it is clear that the composition was modified compared to the original process steel.

I am happy to provide test samples. I’ll PM you to share contact information.



I’ve seen the same “sparkle” in the wrought iron of a barrel tube that I etched with FC. It appears that the sparkle is near the center of the wrought strand, with the edges of the strand not showing this effect. Perhaps the edges are changed by being amalgamated with the steel through the forge welding. Below is a micrograph of an etched damascus barrel.



Below is a micrograph image of a broken section of damascus barrel tube. I literally bent the tube over and snapped it in two. The smooth material is the steel, with its much finer grain structure. The very coarse material is the wrought iron. The black stuff in the wrought iron is the silica. The “sparkle” is the iron grain structure. The sparkles in the broken tube, appear very nearly the same as the sparkles in the etched barrel tube. The material below the gaping split is the chemise.



I have some wrought iron anchor chain material, as well as some wagon tire wrought. The anchor chain appears to me, to be of fairly high silica content. I’ve not had a look at the wagon tire to see how it compares.

The silica strands in wrought are very directional. Below are micrographs of the anchor chain iron. The photo of the end of the iron bar displays small dots of silica. The side of the bar shows long strands. It may be best if I do some manipulations of the wrought material to provide multiple angles of the silica strands. I can twist and then flatten it.

It’s interesting to see in the photo of the end of the bar, all of the pieces that were forge welded together during the piling process of making the wrought iron.

It wouldn't be worth an additional micrograph, but I wonder if a section of wrought was heavily drawn like in a classic barrel if the look would start to change. In Doc Drew's barrel pictures that distinguish wrought iron from steel, the strand appearance of wrought seems to changed to a 'string of bb's' appearance. The slag/silica components seem to be reduced in overall percentage of the wrought, and well surrounded and distributed in the iron.

Great pictures Steve. I've always wondered if the extensive drawing and other working of damascus barrels was to minimize the effects of the inclusions and defects that the early smiths knew were in the raw starting materials. I look forward to seeing what Ken thinks of how it takes his finish, and thanks for the materials and forge time that you're sharing.

The silica would definitely be changed, once made into a barrel tube. Coming out of the reverberatory furnace, the silica is in globules within the iron. During piling and drawing out into bar stock, the globules become long strings. Each occurrence of drawing the bar out, lengthens and thins the strings of silica, as well as works some of the silica out of the iron. Piling, welding and drawing out of the wrought iron is continued until the bar stock retains the desired amount of silica content. There were many grades of wrought iron, each containing a certain amount of silica as was desired for the end use of the material.

After the wrought iron is used with steel to make a riband of damascus, the welding, drawing and twisting of the rods will have made innumerable changes to the shape and size of the silica strings. In looking at a micrograph of a damascus barrel sample, there is no way to know at what angle you are viewing the silica string inclusion. Is it from the side, at the end, or at some angle to the directionality of the string? The view from a single plane, doesn’t tell you much about the overall shape of the inclusion.

The extensive amount of drawing out and manipulating the damascus for barrels was much more about creating the desired damascus pattern, than it was to control the silica inclusions. I believe that the use of wrought iron, with its silica content, was to facilitate the forge welding process. As well as it made the damascus steel softer under the hammer and easier to shape into a barrel tube. I’m certain that they had a preferred silica content for the raw wrought iron material, specified to facilitate the welding and shaping work. But the end result of the silica’s condition in the finished product was very much left to chance.

I've mailed the test pieces of 1002 steel and wrought iron to Ken. Looking forward to seeing the results of the testing.

Daryl, I was confused when I first saw that. But now I believe I am simply looking at an editing error that probably occurred in moving from German to English.

Pete

Very good Steve. Remember that most of the forming took place in the rolling mills. By the time the barrel makers got the ribands, everything was set for them.

Pete

As always thank you Steve.

Sorry Daryl, I missed your post on p.1. Here's another image and I believe only two metals are illustrated

Just on observation, it seems to me that the thing in common with later damascus that was elevated to 'art' was two things. First, the material was drawn to much thinner cross sections, and second, twisting was much tighter and in universal use compared to earlier laminated barrels.

The pictures of the wrought iron that Steve showed had the easily visible classic stringy appearance. The historic damascus barrels do not tend to show that stringing in the wrought, possible because of the amount that it was worked and or drawn out. Steve rightfully pointed out that the damascus images are just two dimensional slices of an unknown area. What can generally be discerned is that some of the images slice through a 'star', which might imply that all angles of the 'grain' of the steel/wrought are being shown, from end grain to side view.

Anyway, for some reason or another the classic stringy appearance of the wrought is significant reduced or generally missing. All I suspected is that the makers figured out they could make stronger barrels by minimizing the likelihood that an inclusion or other defect in the starting material would end up compromising a barrel.

No doubt the art of barrel making was important, but there could've been practical implications....maybe. Only thoughts is all, I look forward to anything Ken might share about Steve's test piece.

An added note I'll include about Washington barrels. There is an obvious lack of visible inclusions in the Wrought Iron. In general, they usually color fault-free. It appears that this may be due to the higher steel content of the tubes. This also may explain why the Riband welds color dark instead of white. DocDrew, have you tensile tested a Washington section? Scrap Washington tubes are hard to come by, but I'd hypothesize that they may be stronger due to the higher steel content.

It's possible that they may have been developed not only for their looks, but to provide stronger tubes as dense smokeless powders became more popular.

Regards
Ken

That is correct, Craig. The more wrought iron is worked, the more the silica content is dispersed and even worked out of the iron. Continually piling, welding and drawing out of wrought iron can bring it to nearly pure iron. In old gun barrels that were made of just wrought iron and scarf welded along their lengths, the silica strings are seldom visible. I believe these barrels were made of wrought iron that had been extensively worked before the iron was used to make the barrel.

I think the wrought iron used for damascus barrels was fairly high in silica content when it was first stacked into the billet. But after welding of the billet, drawing it out into small rods, twisting of the rods, welding the rods into a riband and welding of the barrel tube, a lot of the silica is removed and/or dispersed. I am certain that the high initial silica content was intentional, to aid all of the forge welding that was to ensue. But the barrel makers knew that the silica would be reduced and dispersed by the time the barrel forging was completed.



Ken, I noticed your comment on pre-etching from another thread. You may want to proceed with caution on etching the wrought samples that I sent you. I expect that if you subject them to a five minute etch, you will wind up with a coarse stringy looking surface. Actually, I doubt that an initial etch is necessary on the wrought samples or the 1002 steel, unless it serves to open the grain to accept the rusting acid.

That just makes so much sense. Almost a self fluxing weld with the silica.
I use borax to forge weld & it is the first thing to splash out of the join & fly in all directions. Go hot enough & hard enough & there is definitely none left in the joint.
Those boys really knew their jobs.
O.M

The steel industry in Belgium is changing at this point. They have contracts to build ships. In a few cases, men of war. Also the impact of WWI on the industry was showing. No doubt the changes in powder influenced a small part of the steel industry, barrels for small arms, but not nearly the financial influence of ship building.

Pete

Ken: I've only tested 3 Iron Crolle, Twist, Damascus-Twist, and a single 4 Iron Crolle segment. Without giving away all the good stuff the tensile strength was remarkably consistent at about 54,000 psi. That is just more than 1/2 the tensile strength of lowly Hunter Arms Armor steel.

BTW: It is my opinion that Etoile, "Washington", and Chain patterns use similar lopins/methodology. Check out the Remington 1894 barrels at the beginning here
http://www.picturetrail.com/sfx/album/view/18015717

and this very odd Smith barrel



I understand Bro. Steve is working on a Chain pattern barrel

This is fascinating. My thanks to Doc, Steve and all of you who have contributed expertise and insight to this issue.

Regarding the silica ......... I remember my Grandad telling me about a blacksmith shop that was here on our farm in the early 1900s. The river swamp was being logged and the huge virgin logs were brought out of the swamp and up on the hill by mules and what was called a log cart. It had a big axle under it, likely wrought iron. Grandaddy told of watching the 'smith weld those broken axles back together using white sand as flux. Isn't sand primarily silica?

SRH

Magnificent. Be aware, that pic of the Husqvarna set was only taken midprocess, I've just lacquered it, and will post a pic when totally done.

Regards
Ken

I use anhydrous borax in some of my forge welding work. However, I avoid using flux as much as possible. Flux creates the possibility of flux entrapment in a weld. My time making damascus is too precious to risk flaws in the steel. My steel pieces for damascus are always ground clean when stacked in a billet. After making a weld, I let the billet cool and then cut it up and grind the weld surfaces clean again before restacking. If I use anything at all for a “flux”, I use kerosene.



Sand or ground glass was often used as a flux. It works quite well, however it requires very high heat to melt. Around 2,600F degrees. Wrought iron can stand these high temperatures, but modern high carbon steel cannot. We weld modern steel at around 2,300F degrees. Most of today’s damascus smiths use propane forges. Propane forges struggle to reach 2,600 degrees. Coal forges can reach 3,000F.



Etoile and Washington share similarities. But, chain pattern is vastly different. Chain pattern is very complex in how the lopin/billet is assembled. A hint to its complexity; there are six elements that create the chain links, organized around the four sides of the billet.
I’m certain that the old damascus experts were very good at creating new patterns. But chain is so complex, that I wonder if they actually knew how the pattern would turn out in the finished barrels. I don’t know what they were trying to make with that billet arrangement. But, it wouldn’t surprise me if they looked at a barrel made from this billet arrangement and then said; “Hey, it looks like a chain!”



A cool pattern indeed! Laying up a billet to create the little square elements would take some effort. But, this really isn’t a complicated pattern to make. I will add this photo to the ones that you already sent to me. I am hoping to publish a book on damascus barrel patterns, describing how each of them were made. One of my reasons for working out how to make chain pattern, is to affirm my knowledge on sorting out damascus patterns. If I can’t make it, how can I state that I understand how it is made?



I am currently working on chain pattern, however it is first to be used to make a knife blade. As soon as I post this reply, I will be going out to the shop to continue my work on it. I am very interested in making a chain pattern barrel and have enough of this billet left to do so. But as a businessman, I have to justify the cost. There’s no point in making a barrel, unless you build an entire gun to install it on and shoot it. That is an expensive proposition. I still have the piece that I made, using the first damascus barrel that I made. Despite all of the attention and publicity that this piece has received, I have found no buyer for it. I’m trying to make a living from my work and cannot justify making expensive pieces that few have the funds to purchase. Without a customer to purchase, my work to actually make damascus barrels could cease.

Keep at it brother! And many here certainly appreciate your efforts, starting with figuring out the lopin.

Previously posted, but relevant. Top: Washington or American Flag Left: Double 81 Bernard Middle: Extra-Fine Crolle Right: Chain



Of course how the lopin became the finished pattern is the hard part

And there were multiple patterns referred to as Etoile, Washington, and Chain or Chainette

This is the sample display of Joseph Juleinond de Nessonvaux

Interesting that the Chain segment appears with the Corche and Legia



Etoile and Washington variants



Desire Mineur, of Prayon, Liege, claimed exclusive rights to "Chain-pattern" damascus in 1904, and the process was no doubt a carefully controlled secret

Another interesting Chain pattern by LePage, with prominent 'Stars'



The creativity and artistry still astounds me!!

Germain I hope. From the 1933 "Modern Gunsmithing" by Clyde Baker. (A delightful book really.) Chapter 7, under sub-heading "A FEW SHOP KINKS", he states: "To distinguish between iron and steel, file the surface bright and apply a drop of pure nitric acid. After a minute or two, wash off with water. On wrought iron, the spot will be a pale ash gray; on steel a brownish black, and on cast iron a deep black."

As an aside, while I do not own anything with Damascus barrels, I have thoroughly enjoyed reading about the restorations and seeing the results can take one's breath away.