Rust Bluing

[kritter]

if I remember correctly urine was used for rust blueing not because of the salt content but because it contained traces of ammonia..
a while back I did a little wright up on rust blueing a S&W revolver..as opposed to hot blueing..
if anyone is intrested heres a link to it..
http://www.smithandwessonforums.com/...php?f=18&t=175

[sheepherder]

Originally Posted by kritter

a while back i did a little wright up on rust blueing ...
If anyone is intrested heres a link to it...

+ 1

[Machine Tool]

Excellent job, beautifull

[timn]

Originally Posted by nukem556

Timn , I don't think I can buy into your theory that "all rust is created equal". If this were true, I can't see why gunmakers over the years bothered to concoct complicated formulas to rust blue with. Angier lists many of these in his book....which include substances such as nitric and hydrochloric acids, copper sulfate, ferric chloride, mercuric chloride, and various "tinctures" and "vitriols". If simple rust is going to always produce the same shade of black, you'd think they would have just used a cheap, simple solution of any diluted acid. And if hot bluing is just accelerated rust bluing (which it may be), how do you account for the red/plum color many guns ended up with? I doubt there was a drastic enough temperature difference in the bath to color temper the metal, so it had to be a chemical mixture variation.

Also ,in rust bluing the ferric oxide (rust) is converted to ferrous oxide but the trace elements of the solution are still in the matrix of the finish somewhere.....unless they boil off, which begs the question of why they were added in the first place.....my 2 cents

I apologize for being so tardy in responding.
My wife and I had a terrible bout with the flu and I really fell behind in my work.

Indeed, there are a lot of variants listed in Angier's book. This begs the question, why so many?

I don't know for sure, but I have a couple of theories.

The last publication date is in 1935. We don't know when the recipes were originally compiled or exactly where they came from. Nor do we know which formulas were still in use at the time of writing.

The formulas are not dated. We really have no indication of the chronolgy of use.

Many are slight variations of another. Maybe this was done for marketing or trademark purposes. Perhaps, as people experimented, they found that the same results could be obtained without the "eye of newt" so to speak.

What were left with is no historical context.

Since there were so many "custom" firearm manufacturers ( a smith that built pieces one at a time) maybe each had his own formula made from what was available and worked for him.

We just don't know.

With the advent of modern firearms manufacturing, a repeatable, faster process was called for and the oxidizing formulas became a little more standardized. What we know today as rust blue formulas are the chemical kin of these recipes.



As far as the plum or purple coloring that can occur during the hot caustic process, it is indeed a function of temperature and the alloys in the steel.

The best example I can give you are the "potmetal" like reicevers on old shotguns. Almost invariably they will purple out when put in the tank. Amazingly, even if it comes out only very slightly purple, it will get more and more purple over time.
I automatically either rust or Belgian blue these pieces when they come in.
Some trigger gaurds and floor plates want to do the same thing. It all depends on the make up of the steel and it is temperature that gives them the off color.
Sometimes a variance of 5 degrees will give different results.

I really didn't set out to try to write a treatise on bluing or start any arguments. I only wanted to pass on experience based information about the way steel is colored.

To folks that want to experiment with these processes on their own steel, I wish you nothing but luck and hope I've provided you with useful information and offer any help that I can.

Thanks

[nukem556]

Nice to see your reply, Timn, and that you and yours are feeling better! The flu ain't fun......

I'm a hobby tinkerer and collector, and claim no special knowledge, but I know I've seen original early Lugers that have a definite blue color to them, and as far as I know , all early Lugers were rust blued. Of course, no-one knows what they looked like the day they left the factory...I've heard speculation that age and natural UV light may have made them "bluer" over the years.