History of bluing barrels

[GregLaROCHE]

Can someone give an historical explanations of bluing barrels. Was rust bluing ( the type that gives a brown coating that holds oil to protect from rust) the first, or was it done during the same time period? When did any type of bluing begin to be used?
Thanks

[Winger Ed.]

My understanding is the old school rust bluing is better for rust control, but when hot bluing came along,
it worked well enough, people liked it, and it was cheaper to do.

[M-Tecs]

From what I've read bluing and browning came about for the natural discoloration of the bright metal. Once it was discovered that the discoloration gave addition protect it was incorporated into the manufacturing process.

[K43]

In the 1860s Colt used to "flame blue" or heat blue revolver parts somehow. I don't know the process. Many military barrels and locks were still left bright. I think that was to give privates something to do (polishing) so they didn't have idle time to get in trouble.

[GregLaROCHE]

I have an old double barrel muzzle loading shotgun. The lock is still bright but the barrels are brown. I am wondering if I should clean them up to bright or leave them the way they are. I was once told that rubbing a barrel with salt and oil would rust blue it.

In the French army, with the introduction of the Chassepot, soldiers were forbidden to polish their barrels to bright, as was the tradition before. The reasoning was that the reflection could give away their position.

[DaleT]

Having made several flinters of the colonial age, I browned the barrels.
I used a commercial solution called barrel brown , wipe a thin coat on and put the barrel in a humidity box overnight, take it out and lightly card off the rust
wipe another thin coat wait repeat until my desired Brown.
I'm not a chemist by any means but I would think metal shavings in a mild acid ( I think Hershal House used a method similar) would create a rust solution to be used in the above manner.

[schutzen-jager]

In the 1860s Colt used to "flame blue" or heat blue revolver parts somehow. I don't know the process. Many military barrels and locks were still left bright. I think that was to give privates something to do (polishing) so they didn't have idle time to get in trouble.

iirc - the small parts were placed in a metal box containing bone charcoal + baking them in a oven =

[Castaway]

Schutzen-jager. What you described is case hardening. Although similar to flame bluing which doesn’t involve carbon or bones, it’s a different process altogether. Flame bluing does however result in some case hardening

[HWooldridge]

Firearms were initially polished and kept bright, similar to armor. I suspect that was quite difficult to maintain in the field so people eventually gave up and decided to maintain a natural rust, but the appearance was likely not consistent, so intentional rusting or "browning", became common practice. Bluing came along later, as improvements were made in processing and chemistry.

[country gent]

Most early military arms werent blued as it was seen as cosmetic and an added expense. As the "reach of military weapons ( and actual sights) the were colored to reduce glares to aid sighting. One of the favorites was parkerizing. Bluing was done over a very lightly polished surface to get a matte finish. The civilian muzzle loaders were blued or browned as desired.

Heat bluing is done at around 1400* in an oxygen free environment. Steels take on the bright blue at this temp or around it. They go thru a yellow straw purple then the blues, If there is no quench then it actually softens the parts. Case hardening is done in a pack of charcoal bone and leather to keep oxygen In the container these materials didnt really burn once the oxygen was gone and was a pure enviroment and when up to temp it is quenched producing the vibrant colors. Color case hardening is delicate and will fade if exposed to sunlight over time. It is normally protected with a thin varnish applied over it. I have read where colt cleaned parts to be colored in boiling gasoline.

[schutzen-jager]

Schutzen-jager. What you described is case hardening. Although similar to flame bluing which doesn’t involve carbon or bones, it’s a different process altogether. Flame bluing does however result in some case hardening

it was for bluing + not casehardening, which was a different process - see link + numerous descriptions of charcoal bluing -

https://www.bing.com/search?q=colt+b...ods&FORM=QSRE1

[ Prior to 1939, Colt used a charcoal bluing process which produced some of the best bluing in history, but the amount of labor and time involved necessitated a change to “hot salt” bluing or “black oxide” bluing which is the process used by the industry today. Bluing is really a controlled “rust” process. It can be done a number of ways. ]

https://www.youtube.com/watch?v=aq8sW3ROq5Y

[405grain]

If your barrels are already brown do not remove the browning so that you can "blue" them. When doing a rust blue you convert the brown rust to blue (actually black), by boiling it in water for 20 to 30 minutes. Two things: first the barrel must be completely clean of oils, grease, or dirt. Only handle the barrel with rubber gloves both while cleaning it, and afterwards, to prevent getting oily fingerprints on the metal. Second: the water has to be already boiling before the barrel is placed in it. Boiling drives the dissolved oxygen out of the water. The boiling water will convert the brown "rust" into black "rust". The boiling water will not affect the bore because 1. it will not have any dissolved oxygen in it to oxidize the bare metal, and 2. it will evaporate way too quickly to cause corrosion after the barrel is removed from the water.

Once the browned barrel has been boiled it will look terrible. There will be powdery brown rust dust all over it. This is easily wiped off. The bore should also be swabbed clean with some oiled patches. Once the barrel has had the powdered brown rust particles wiped off it will look black, but dull. The barrel needs to be "carded". A special "carding wheel" can be used to do this, or some strips made from an old pair of denim jeans can be used to buff the barrel like a shoe shine. Once buffed the barrel will be shiny and black. You should then take a little gun oil on a rag and wipe down the barrel.

Before you go to any of this effort try out the process first. Get a piece of scrap steel and sand it to remove any scale and expose the bare metal. Now place this piece of metal in some vinegar and leave it until it turns brown with rust. You don't want actual pitting, but if you can rub off most of the rust with a rag it needs more time soaking. Once this piece of scrap metal is "browned", get a pot of water boiling and place the scrap metal in the pan. It doesn't need to be distilled water or anything, ordinary tap water will do just fine. Boil the part for at least 20 minutes. If you need to, flip the part over so that the boiling water can act against all it's surfaces. After 20 minutes pull it out of the water and wipe any "rust dust" off of it. The part should be black. Buff the part and it should be shiny and black. A light coat of oil and the "part" is done.

BTW: rubbing a barrel with salt and oil will not rust blue it, it will only rust it - and not necessarily in a good way.