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.

Originally Posted By: Steve Culver
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?


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.

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