Rust Bluing

[Olle]

Tim,

You are making some interesting points that also confirm what I have found. Just as you say, black oxide is black, so the blue color is not really the color of the bluing. It usually appears after you oil it so it's just a trick of the light, much like what you see in a rainbow or an oil slick on water. However, I have seen guns that have a slight blue hue to them even when dry (for example, my FN/Browning 1900) but they have all been quite old. This makes me think that aging possibly does something to the finish, not to the oxide color itself but to its surface. It also seems like machined and unpolished parts often get a blue sheen to them when you rust blue, so I'm trying to figure out if there is a way to prep other parts (by wire brushing, burnishing etc) to get the same result.

I usually do the final polishing with fresh paper, as I want all parts to have the very same finish before I blue them. The grit will wear gradually so I have never had any luck getting an even prep using worn paper, it's either too worn or not worn enough. I usually use fresh 600 for the final polish, it gives the rust a good bite but is still fine enough for the rust to etch away any directional polishing marks.

And yes, I'd love to see a picture or two of your 1911. I have found that a lot of the appearance is in the accents, and I have used temper colors with good results. Nitre bluing is probably next on my agenda and the only reason why I haven't used it yet is the possible safety issues, but I'm hoping to get my shop area closed off so the family (including the £$#¤% cats) absolutely positively can't get access to it.

[nukem556]

I'm still a relative newby here, but I'm pretty sure I havent seen any recent posts by Mr chuckc...anyone know of he's still around?

[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

[nukem556]

I'm just about ready to mix up a batch of the formula that chuckc wrote about in his archived posts....I'll try to post some pics of samples of it compared to a couple other available rust blues.

[sheepherder]

A little bit off-topic, but what solution/brand is best to get the brownish-"patina" finish that all old guns seem to end up with??? I have an old gun with some patina on it; I'd like to do it all in that worn brown coloring...

[Olle]

Originally Posted by postino

A little bit off-topic, but what solution/brand is best to get the brownish-"patina" finish that all old guns seem to end up with??? I have an old gun with some patina on it; I'd like to do it all in that worn brown coloring...

You probably want something like the browning you see on some antique guns. Browning and rust bluing is actually the same process. When you're bluing, you boil the parts in water to convert the red oxide to black oxide so the only difference is that you don't boil the parts.

Brownells and Pilkingtons formulas will usually give me a mix of red and black oxide (some parts turn black already when I apply the formula), so I would try somehing less agressive. You could possibly dilute it a bit as well to avoid the black oxide.

Once you're happy with the finish, you rinse in water and oil the parts. Some say that you also have to neutralize in baking soda, but I'm not so sure that this is necessary as long as you rinse good.