blued barrels/bores

[Artificer]

:bull: If hot bluing is not rust then why would one need to use "Rust Veto"

OK, not being a Chemist, I stayed out of the discussion on whether hot bluing was rust or not.

OK, so why the rust veto? Simple. Even Hot Bluing will not completely stop rust from forming on the metal if one doesn't coat the metal with oil or some kind of preservative. For example, if one took a barrel that had been hot blued and cleaned it completely with Acetone and put it up that way, it is going to rust in a few days to a couple weeks without some kind of protective/preservative coating.

Gus

 

[Zonie]

Browning or bluing including "heat bluing" or tempering colors is caused by a form of iron oxide (various types of rust) on the surface of a steel part.

By itself the oxide does not protect the underlying surface from rust.

The oxide will absorb oil so coating the blued/browned/heat blued part with oil will keep oxygen from being able to get to the steel.

This protection is the primary reason bluing/browning/heat bluing is/was done to guns/knives/swords and armor.

Also, without his black armor on, how would we know that knight was the bad guy? :rotf:

 

[George]

Perhaps on my next build I will go through the hassle of charcoal bluing again if there doesn't seem to be any other way to protect the bore.

Strange how what we "know" about stuff changes with time. It apparently seems correct to some that charcoal blueing protects the bore, but in late 18th century the old boys decided just the opposite, that it damaged the bore.

Wm. Cleator, An Essay on Shooting, 1789, England:

"The last operation is that of colouring the barrel, previous to which it is polished with fine emery and oil, until it presents to the eye throughout its whole length, and in whatever direction we observe it, a perfectly smooth, equal, and splendid surface. Formerly, barrels were coloured by exposing them to a degree of heat which produced an elegant blue tinge; but as this effect arises from a degree of calcinatiion taking place upon the surface of the metal, the inside of the barrel always suffered by undergoing the same change. This, therefore, added to the painful sensation excited in the eye by looking along a barrel so coloured, has caused the practice of blueing to be disused for some time past. Instead of it, barrels are now browned, as it is termed. To do this, the barrel is rubbed over with aqua fortis [nitric acid] or spirit of salt [hydrochloric acid], diluted with water, and laid by until a complete coat of rust is formed upon it; a little oil is then applied; and the surface being rubbed dry, it is polished by means of a hard brush, and bees wax."

Spence

 

[Black Jaque Janaviac]

Thanks for the quote Spence. I can't quite decypher the meaning of it though. The bore "suffered" but in what way? Something about it being a pain to the eye, but who cares? I don't go looking down the bore often anyway.

 

[George]

That bit about hurting the eyes is about the outside of the barrel, not the bore. Blued barrels are smoother than browned ones and reflect light more, so I guess that's what he was talking about.

He says the bore is damaged by "calcination". I believe that is what we would call oxidation, today. Of course rust is a sort of oxidation, so I presume they believed the surface of the bore would be degraded in some way.

Spence

 

[Artificer]

Hi Spence,

As we have discussed before, I am amazed at how much Cleator "got right" about ballistics and many other things, before there were ways to scientifically test things.

However, I don't understand where Cleator came up with heat bluing being injurious to the bore. Heat bluing provides a very little amount of protection as it aids the surface retaining oil, as Zonie pointed out above. However, since heat bluing leaves usually such a thin coating of oxide, it wears off rather easily.

I wonder if because heat bluing wears off, Cleator may have meant it was more difficult to look down the barrel at an angle one could see down the bore and be confused between bluing and black powder residue?

Have to admit I'm groping for an explanation here.

Gus

 

[coloradoclyde]

Just because the color is blue, doesn't mean that all types of bluing are equal. Same goes for types of steel....Which they didn't have in the 18th century....At least nothing similar to today.

Folks often confuse Iron oxide(II) with Iron oxide (III)
And everyone ignores Iron(II) Iron(III) oxide

Rust consists of hydrated iron(III) oxides

 

[George]

I don't know what they thought the damage was, but I doubt it was just that it made looking down the barrel a problem. Whatever it was, in their time as well as ours, believing a thing doesn't guarantee it's true.

Since charcoal blueing was old technology in Cleator's day, I assume that's what he was referring to when he described blue as a result of heat, but that's speculation on my part. Don't I remember reading somewhere that if a section of the barrel had to be heated after the reaming/polishing of the bore had been done, then it had to be done again?

Spence

 

[Artificer]

Not sure what you mean?

Barrels in the time of Cleator's treatise still made from Iron, steel wasn't used for barrels in England for another two or three decades.

"Formerly, barrels were coloured by exposing them to a degree of heat which produced an elegant blue tinge;"

This quote tells me Cleator was only talking about "heat bluing" and not rust bluing, as he made no mention of anything other than using heat. Cleator goes into great detail on many things and when he did not mention other things to go along with heating the barrel, then he was only talking about heat bluing. IOW heating the Iron barrels above purple heat into the blue range.

Gus

 

[Elnathan]

Don't I remember reading somewhere that if a section of the barrel had to be heated after the reaming/polishing of the bore had been done, then it had to be done again?

Spence

If you heat a piece of steel up to red-hot or even a bit less, it will oxidize, produce scale on the surface, etc. Forged items tend to have a rough surface and spots of hard, glassy stuff and look pretty gnarly if they haven't been very well brushed off during the forging process. That will force you to repolish.

In charcoal bluing, the charcoal functioned to keep oxygen away from the metal and helped prevent scaling. I believe that you can get the same result by wrapping the barrel tightly in foil and heating in an oven - Jerry White gave us his method for bluing barrels that way over on ALR some months back.

 

[Zonie]

The blue resulting in heat bluing appears at around 560°-570° F.

This temperature won't cause the surface to roughen or to appreciably change size or shape unless there are some major stresses in the part.

The bottom line is, no additional machining or re-machining is needed if the part is heat blued.

 

[Tinker2]

Reducing its tendency to rust and hardening the surface.

Yep.




William Alexander

 

[Tinker2]

If it's a basic massed produced kit gun, wouldn't be surprised if they're made of the cheapest bbl material known to man - 12L14.

You’re funny
:rotf: :rotf:




William Alexander

 

[Artificer]

In the Journal of Historical Armsmaking, Volume 3, there is a copy of "The Gunmaker and the Gunstocker" written in German in 1771. In addition to the German language version there is a translation to English. Vol 4 has a description of a gun factory (in German with English translation).

Not sure which one mentions it without spending too much time pulling out my copies and looking them up, but I think Volume 4 mentions of all the gun workers at the rather large German gun factory, only one or two were allowed to charcoal/heat blue barrels, locks and sword blades. This because it was difficult to do just by eyeball in the period.

Gus

 

[George]

A nice early reference to charcoal blueing in Portugal.

The Perfect Gun and rules for it use together with necessary instructions for its construction and precepts for good aiming

Dedicated to His Most Honourable Majesty the King of Portugal D. Joaõ V.

By two brothers Cesar Fiosconi & Jordam Guserio

Printed by Antonio Pedrozo Galram with all necessary licenses Anno 1718

Chapter XL Concerning the manner of giving colour to Barrels

When the barrel has been planed, water shall be made to flow very straight along it, without intervals in the middle, and the edges of the muzzle shall be broken inside, so that it is rounded, and when this is finished it shall be given its black or bluish colour in the forge.

In order to give the black colour there shall be made a brazier of charcoal that gives no smoke in the forge, and when it is well burnt, the barrel shall be placed among the embers, where it shall remain until it turns from blue to black, and then it shall be withdrawn so that the colour may be everywhere without patches. In the same way the blue colour is given in embers of the furnace, also without there being any smoke, more care being taken with this colour that it does not pass the blueness, because if there be any lack of care and it be retained too long in the heat, the colour will change, and to give it the proper colour there will be no other solution except to whiten the piece again. Thus all the parts of the locks are made blue, and the cleaner and brighter they are when they are taken to the forge, the better will be their colour become, and they will be more pleasing.

Spence

 

[Artificer]

"When the barrel has been planed, water shall be made to flow very straight along it, without intervals in the middle, and the edges of the muzzle shall be broken inside, so that it is rounded, and when this is finished it shall be given its black or bluish colour in the forge."

Wow, that is really detailed information. By doing the muzzle that way before the finish, it ensured the bore was properly crowned and would also be protected by the finish when used. I'm really impressed.

Gus

 

[M. De Land]

Rust bluing or browning require the bore to be treated with a non oil rust preventative and plugged as one does not want to etch the bore with aggressive solutions.
I like and use Brownell's "Hold" which dries and seals the steel from oxidation then driving in wood pegs treated with the solution as well.
I do quite a bit of rust bluing and browning!

 

[nhmoose]

"Hold" is bad stuff. Read all the warnings. Our shop passed on that for a reason.

Serious oxygen absorber do not inhale or get on skin or eyes. Reminds me of CO or cyanides.

Using a process that the bore needs to be plugged we used polyurethane on the plugs and Du-lites quick seal inside.