Rust Bluing
 

A number of years ago I restored a couple of Lugers for my own collection. The rust bluing solution was sold by Stoeger. The finish on my Lugers with the Stoeger rust bluing is a blue-black color like the original DWM finishes.

More recently I have restored a Luger with Pilkingtons bluing. The finish is very dark, black. The Luger is an early Navy that should be more blue.

Does anyone know of a commercial rust bluing solution that will finish in a blue-black color.

All guidance will be appreciated.

Dick

Dick,
I like Brownell's DICROPAN "IM".
Hugh

roy dunlap acid blue
 

formula

nitric acid 4oz
hydrochloric acid 3oz
iron 1/2 lb
distilled water 1 quart

I would try a Belgian Blue like Herter's or even Brownell's Classic Rust blue. These both have a nice blue black look to them with not as much black.

Laurel Mountain Forge is very easy to use and gives good results, but it's not very "blue" either. The old Angier/Dunlap formula is a moot point.... you go try to buy nitric acid without having Homeland Security or the ATF come down or your butt!

How would apply it and mix it please?
Alf.

The absolutely important thing to remember is ADD THE ACID TO THE WATER...SLOWLY!!...NEVER ADD THE WATER TO THE ACID!!! If you pour the water into the acid it will flash boil and explode. More than one student has learned this the hard way in the laboratory and got severe acid burns.

As I recall you mix the acids together and add the nails. After the nails have dissolved, add the mixture slowly to the water. You need to use a crock or glass vessel. After it is mixed thoroughly, put the final mixture in a dark glass bottle, sunlight weakens the bluing solution. Oh by the way, it is probably best to do this all outside...that stuff stinks.

Hope I got that all right...I take no responsibility for any foolish attempt to make this stuff, it can be hazardous.

Using the solution to rust blue a gun is another whole process that involves swabbing the solution on very well cleaned metal, rusting it in a steam box, boiling the gun/part and carding off the rust, repeating several times until the desired depth of blue is achieved. I'll let someone else do the honors of writing that up.

Originally Posted by hank678417
formula

nitric acid 4oz
hydrochloric acid 3oz
iron 1/2 lb
distilled water 1 quart

This is very close to the old Neidner formula.
Used correctly, you can get different "colorings" depending on the steel.

I refinished (again) my 1911 this way and it turned out exactly like I wanted.

CAUTION: Mixing these chemicals is dangerous.

AAA... Alway Add Acid to water.

When The iron (I used baling wire) is added to the acids it produces a very toxic gas. Do this outside with some breathing protection.

well, you guys must have connections, because I can find NO ONE that will sell nitric acid to a private individual!

A good industrial cleaning supply house will sell it to you by the gallon.

That's way too much for a casual user just to make up a small batch of rust blue solution. By the time you get all the acids you will have spent as much as a bottle of commercial solution will cost you.
Plus, you don't have to deal with the dangers and experimentation to get the solution to work the way you want.

You would be far better off to just by some Pilkinton's or similar solution.

The color you get really depends on the way and amount of polishing on the steel and the number of "trips" you make.

It's a slow process and requires a lot of patience to get the best results.

It is worth the effort, but it doesn't happen quickly.

probably basic - but these I havent seen discussed anywhere ...

anybody know the best way to protect the barrel bore/rifling/chamber from any damage during the repetitive solution / boiling steps in rust blue process ?

how did dwm achieve the bright interior surfaces that seem to show no overflow of the solution during application ?

what is range of polishing for excellent bluing result - ie say 400 grit paper thru chrome like shine ?

best way to protect orignal proofs and other markings as much as possible ?

thanks
Bill

If you are seriously contemplating slow rust bluing, buy a small bottle of a good commercial solution. It will come with all the information you need.

One of the major factors determining the outcome is cleanliness.
The steel MUST be clean and oil free.
I use a mixture of Simple green and ammonia for basic cleaning.
A very hot water (180-200 degrees F) bath of TSP or dishwashing liquid in water helps to remove deeply imbedded oils. The small screw holes in receivers tend to hold minute bits of oil that will bleed onto the surface when you boil off the red oxide and ruin your hard work.

Rust bluing is not difficult. It takes patience and attention to each detail.
Practice on some small bits of scrap before you do your prized gun.

Good luck with your project.

Tim

Tim,

thanks !!! so much for the useful answers and added info

I do have a project under way and have found that using arkansas type flat stones works quite well to maintain flats and seems to match about a 400-500 3m wet/dry finish

my main interest is custom target lugers that will be obvious not originals

I suspect some sort of tumbling for some parts would work if not done too long - esp for the irregular shaped parts , then dress with stone or paper , protect tolerance surfaces with tape in the tumbler

Ive used the brownells rust blue many years ago on a simple case browning hipower and that was quite easy to do

this is sculpture in metal which seems to be a good hobby to me

I suspect a henrob type torch and low heat would allow filling pits and then dress them down with stone - havent tried that yet

just dont do the chemical stuff in closed spaces

thanks
Bill

There seems to be some confusion regarding the grit sometimes, and I'm not really sure that all grits are the same (paper, compound, abrasive pads etc). Are you talking about P400 paper or polishing compound?

I use paper and elbow grease for most of the polish (I don't trust myself with power tools around guns), but a fresh P400 paper gives me a brushed finish. It still seems to be a good base for the bluing, after a few cardings you can't see it anymore. I have even tried a light blasting with aluminum oxide, and it did require a heavier carding but came out almost as smooth as a 400-600 grit polish.

It would also be interesting if someone could elaborate a bit on how to get different colors. The only variation I have seen has been because of the steel quality, but some say that you can get different results by using different chemicals.

THATS the $64,000 question...how to get that elusive true blue you see on early Lugers...I haven't seen any commercial solutions that match it, theyre all a lot blacker. Those who can replicate it won't tell anyone else how they do it. Also, on older Lugers you can see the grain of the polish in the metal, which usually disappears after a few cardings with modern solutions.

I just bought a mismatch with a near mint early DWM frame, and the color is a dark charcoal color that gets a blue hue when you oil it. In other words, it's exactly what I get with pretty much any commercial solution. There are some faint polish marks, but they seem to be from the final carding and not from the metal prep.

I'm wondering if the blue color you see on some guns simply has to do with aging. After all, many Lugers are 100+ years old so it's not too far fetched to believe that something has happened to it through the years. Or does the color vary between the brands?

Since you have obviously done some experimenting, you have started discovering the "secrets" to a good finish.

When I said a 320 to 400 polish, I was talking about a sandpaper finish.
A true 400 polish with paper should look very shiny. If you you look closely though, you can see the very fine lines left by the paper.
These can be blended somewhat using a carding wheel.

You are right about using a fresh sheet. It will change the way light is reflected. For a glossier finish, use the 400 till the steel is bright. Something else to try, after it's polished out, turn the paper over and polish with the back side.

Bluing steel,or as it once was called, blacking, is a process of rusting. All you are doing is converting red oxide into black oxide.
That is true in rust bluing and hot bluing. It just happens a lot faster in the hot process.

There is no such animal named blue oxide.

In these processes, our only real variable is the way light gets reflected off of the surfaces (polishing) and the alloys in the steel.

There is a true blueing process. It's called carbona or carbonia, depending on who you ask. This is a heat process akin to color case hardening.

Another method is nitre bluing. Again, it's a heat process. The straw colorings you see on Lugers are a variation of this process.

If the surface of your steel is polished out correctly, the final coloring is dependent on the number of "trips" through the rust, boil, card process and the makeup of the steel.

Also, you can not hide any blemishes when rust bluing. Except for color, the appearance of the steel before bluing is exactly the way it's going to appear when blued.

I really wish I could give you a formula or process that works exactly the same way everytime, but it doesn't exist.

The best thing about working on your own guns is there is no rush. If you don't like the result, you can start over and try sanding a different direction or polishing it out more, or less.

Most any good refinish job will have some blue color when oiled. It's simply the way light gets reflected.

Take your time, be patient, ang good luck with your project.

If you would like to see an example of rust blue combined with nitre blue accents, I will post a photo of my 1911.

Tim

do a search here using member name "chuckc"... he has an interesting thread about rusting formulas......always kind of hard to evaluate by pictures, but he shows a side by side comparison of a few samples with different solutions...it looks to my eye that he did get some subtle differences in color

Here's a direct link to ChuckC's posting:

http://forum.lugerforum.com/showthread.php?t=13002

The combination of these discussions would make a nice stickie...

Marc

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. :)