Finishing Metals; Firearms & Knives

[Charles Owlen Picket]

First of all I would like to thank sincerely the uploaded & availability of the AGI videos as they have been really great: enjoyable & informative.

Unfortunately the bluing & re-finishing videos (often others) simply made mention of purchasing chemicals from Brownell's. The instructor did make mention of various acids in a Bluing video (& Parkerizing). He mentioned most common acids but no ratio or proportions. {Simply, "buy it from Brownell's". Well, I have a fairly well stocked lab I can access and want to really learn this as an art.}

I hunted for further information....it was VERY tough to find! It seems that most of the information was kept quite for the purposes of selling pre-packaged products. My question, therefore has to do with other's experience or knowledge of what chemicals & proportions have been used in Parkerizing and bluing.

I did finally find a site that made mention of the use of nickel nitrate in the formulation of the green in military Parkerizing. But it's been quite a tough thing to find really in depth chemical or conceptual information.

Does anyone have any additional information or tips on where I could get this information? The USPO turned up little in the specifics of WHAT chemicals and proportions to use. The techniques were outlined in the patents but the videos actually did a better job explaining the "nuts & bolts" approach.

I wanted to start metal re-finishing both knives and guns and have quite a bit of materials to do so but I need more information that I suppose are trade secrets. ANY help or direction would be deeply appreciated.

[Cobalt.45]

Last year I lifted this from http://www.finishing.com/index.html

"I read with interest all about steel bluing at your forum and noted that it looks like a very simple and effective bluing method widely known among russian hobbists is not known in US. Recently I have nicely reblued my C96 Mauser pistol using this method.

"This is a hot process so not suitable for double barreled guns. The chemical needed is the only one - natrium nitrat (NaNO3, very chip, sold in flakes, used in agriculture, also known as Selitra). The all you need are: 1. preferably new 10 dollar nichrome spiral type electric heater of 1kWatt. 2. suitable size metal pot (I used half of 1 gallon can cut with scissors). 3. piece of cardboard or old plywood 1x1 meter. Put flakes into pot and heat untill flakes melt (approx 320-350C). There are almost no fumes if pot was clean enough. When flakes became a fluid add more if required to top over your work. Parts to be blued must be stripped of old blue and polished. It is not required to do chemical degreasing, just whip parts with cloth wetted in Acetone and dip them into hot bath and watch (I noted that even not thouroughly cleaned parts, with fingerprints also come out nicely as fat gets burned away easily). In 3-5 minutes they turn to be of nice dark blue color, the longer the darker. When done, get parts out "-SNIP-

I realize this is not what you asked for, but maybe there is something to the process cited.

In any event, the site has a good deal of info on bluing metal. I used "hot bluing solution" as a search and got many hits.

The site says they have archived over 40,000 Q&A's on metal finishing.

[Charles Owlen Picket]

....this is a VERY good start off! Thanks!

The films were very interesting in that a "real rust blue" resists rust but is labour intensive. Well that's not a big deal but modern weapons manufacturers don't do that any more (for the most past).
The web page has VERY interesting info in it. The idea of refinishing stainless steel knives that are blackened from the manufacturer has always interested me.

This also leads to a very interesting issue of a blade that is considered to be "poisoned". Indonesian Kris knives use arsenic I am told in their forging (I don't know this for a fact at all) but I have heard that they were often termed as being poisoned (?). The area leads to various subjects as off-shoots.

This is an art as well as a mechanical technique and I am really interested in learning all I can about it.

[monkeyboy]

I don't know if you've got The Modern Gunsmith, but vol 2 has some good stuff about bluing, chapter 16, pg 209:
http://rapidshare.com/files/51110472/The_Modern_Gunsmith_v2.pdf
Vol 1? OK:
http://rapidshare.com/files/51109744/The_Modern_Gunsmith_V1.pdf
A short section can be found in this book, but he gives some good info on making containers & ovens that might be helpful:
http://rapidshare.com/files/51106968/GUNSMITHING_AND_TOOL_MAKING_BIBLE_by__H._HOFFMAN.p df

I was curious about the poisoned blade, so I did a little research. I couldn't find anything other than references to the video game "Final Fantasy" and the "Crysknife" used in the book Dune, you're not making 'em from sandworm teeth, are you?

Also found this on Wikipedia:
"However, the slashing wound made by kris is terrible. The edge of the blade "danced" in the wound, and left the tatters of dead flesh, which began to rot. This is the reason why all sinuous blades were considered inhuman all over Europe"

MMMM, rotting flesh. Not poison, but still pretty nasty!

In my search I found this website:
http://www.sharpblades.net/
Which I thought was pretty good...

[Charles Owlen Picket]

Thanks very much for the info. I certainly don't mean to go off topic in my own query but to address that question:

Actually I was at a gun show (so consider the source) many years back and someone was selling his collection of Kris knives from Indonesia (Java, etc) and made a comment to the effect of "these were forged with an arsenic salt, so I keep these behind glass and these aren't", etc, etc, etc. I asked what he meant and he started talking about the whole poison blade issue....

Would that be enough to produce any effect? I doubt it but it could result in some infection due to the course & open folding of the steel and the remnants of foreign material in the folds. That concept, in itself opens a whole subject of poison retention on a blade. Anyone could simply dip a knife in poison but for it to RETAIN the poison...that's a trick!

Frankly I would like that (poison) to be on the tip and not on the edge to prevent self-inflicted issues from arising during a dispute. It's easy to get a little cut on oneself while doing what needs to be done but to stab there needs to be a pointed effort (that was bad, I'm sorry....).

Frankly it sounded like BS but there are some strange things in this world and I don't know everything so I keep an open mind unless the BS is too much to ignore.

[Bugger]

Arsenic in the alloy from which the blade is forged? Because of the size of the required lethal dose of arsenic, and its being present in an alloy which surely would not dissolve on contact with flesh, there is no way that that could kill. Besides, arsenic in an alloy would make it brittle, and unsuitable in a knife-blade

[chemdude1999]

C.O.P.:

Sounds like a bit of BS.

Arsenic is more of a cumulative poison. Also, note that arsenic is highly overrated. It takes a long time to do any damage. The liver can handle moderate doses of it by breaking it down. Of course, this is taxing on the organ and does have an effect. It's just not a overwhelming system shutdown.

Pentavalent arsenic and its more toxic derivative, trivalent arsenic, are slowly but completely metabolized by the liver. Basically, they are methylated into a harmless metabolite that is excreted in the urine. The majority is eliminated in about a week with the rest taking several weeks to evacuate.

Having said all that, arsenic is still toxic (especially the trivalent form). It is considered a carcinogen and a teratogen (birth defects). So, unless you have the patience of Job and really hate somebody, it's not practical.

If the story of the blades is true, there wouldn't be nearly enough residual arsenic to do anything. The cutting action would be far more effective in killing. :p

On the original topic, many of the new "paint" finishes are outstanding. I have one on a DSA FAL and it is very nice. If you need traditional blueing and such, Brownell's DOES have some excellent products. But, I do understand your want of knowledge.

[nbk2000]

I could see some of the arsenic oxidizing in the surface of the blade, and then that arsenic being deposited in a wound.

Not enough to kill in of itself, but the arsenic deposited in the wound could cause local tissue necrosis, resulting in death by septic shock at some later date.

[Charles Owlen Picket]

Please don't get me wrong it DID sound like BS to me but I am really trying to find source on this...I'll tell you what I heard: that the blades WERE VERY brittle and that was why their design was such (if you've seen Javanese Kris they are a bit strange) that they utilized a technique to thrust and not cut. In fact their brittleness was their hallmark - that is well documented.

The above sited concept of necrosis at wound site appears to be right on target. As I certainly don't men to imply that they were poisoned to the extent that would commonly be associated with a "poisoned arrow" (i.e. instant incapacitation). The concept is intriguing to me however.

[User32]

I didn't include an actual link in the AGI Bluing videos but did mention blindhogg.com for more information on making your own salts.

http://www.blindhogg.com/homemadesalts.html


More information on other refinishing ideas can also be found here :

http://www.blindhogg.com/refinishing.html

[Charles Owlen Picket]

@ USER32
I pride myself in finding things on the net and in general. However that was a site I had not seen.
A sincere thank you!

I am now in the process of doing some lightweight experiments and will post some results. The "paint on" finishes are not all that bad. It's not really my cup of tea as the real thing is more of the hobby that gets my interest but I saw a Remington 700 that someone did with the bake-on product and it looked pretty good.

However.....I saw an older Colt Trooper MKIII and Series 70 w/ their high end blue and - brother - that is some bluing! The secret I am told is in the prep and the physical tanks, etc. The chems are not tough for me to get so I know I can put out a decent product if I put my mind to it and get more and more study materials....... they are much appreciated.

[User32]

80 percent of any finish out come is metal preparation, no matter what finish you are using. Metal prep is very important when you start getting into finishes like Nitre Blue or Acid Blue. They aren't as forgiving at hiding imperfections as the spray on coatings are.

I've used Brownells Gun Kote on FALs, AR-15s and a few 1911s. It holds up rather well if you take the time to prep the metal surface correctly.
Any traces of oil or dirt and the finish will chip in that area.

You can use a toaster oven for baking 1911 size pistols and parts. I'm finishing up a Springfield mil spec with the Matte Black GunKote in a cheap
toaster oven picked up at a local store on clearance. It's working rather well.

Great results are very possible without spending tons of money on equipment.

[chemdude1999]

Excellent find, User32. I think that might be my next ripping project. I'll post it on Rapidshare if I do.

I have Gun Kote on the FAL I mentioned above. After a particularly grueling shooting session, I took the gas-plug and a few other small parts to work and sonicated them. The paint did discolor a bit, but overall held up quite well to the harsh cleaning.

C.O.P. good luck with your bluing projects. I would recommend wearing a heavy apron and a face shield when you move on to big stuff. The added safety allows you to concentrate on your product instead of a little chemical drip on your face. I spilled a bit of sulfuric on my finger at work the other day. I was making a batch of reagent. I tried to finish it but had to run to the sink with searing pain. Gloves from now on. :o

[Charles Owlen Picket]

Oh yes! I learned quite a long time back my skin is not armor.

At this point I have some information indicating that the ingredient in green WWII-era parkerizing (the real green parkerizing) is nickel nitrate. I may be able to do some experimenting this weekend and will post results if I honestly believe that the results have merit beyond a simple green finish.

I have also done some anodizing to clean up an alloy frame on a shooter handgun (also sodium hydroxide but using high current low voltage current, etc) and the results look great. The question is; will it last? I have found that there exists a chemical touch-up for scratches for blue/black alloy frames that uses selenium dioxide. It's not cheap (500gr costs about $80 but lasts a Hell of a long time) but works well if the aim is to clean up a piece that has but a few scratches and complete strip down anodizing is unwarranted.

I can only say that those of you who have contributed to the common knowledge-base; a very sincere "thank you"! When you guys post leads or whole re-prints, that stuff is GOLD!

[Cobalt.45]

This is a link to the page at americangunsmith.com that has several videos on applying different types of finishes to firearms:

http://www.americangunsmith.com/index.php?id=22

[Gunjack]

Nitrite black:
According to various authors(gunsmiths) a temper-black can be obtained in a few minutes by immersing the parts in a flux composed of 80parts caustic soda and 20 parts potassium nitrite,then washed and oiled.
The coating is durable and liable to after-rust.

I've tried it and it works.

Caustic soda brown:

Alkaline baths with added oxidants for browning soon lose their effectiveness, as the carbonate formed by absorption of atmospheric carbonic acid hinders the oxidation of the metal.
The products of reduction and decomposition accumulate, so that the oxidising power of the bath is soon exhausted.
By adding slaked lime to the bath the caustic alkali is continuously regenerated,promoting oxidation,and the formation of carbonate,with its harmfull accompaniments, restrained.
Most inorganic oxidants can be used,such as dichromates,permanganates,nitrates,peroxides and chlorates, also aromatec nitro compounds.
According to concentration and nature of metal deep black to bronze-and brass-coloured coatings can be obtained.

Mode of working:
Polished iron parts can for instance be coloured black in 20 to 30 minutes, according to their size,in a bath of 100 parts of 33% caustic soda lye, heated to 120-130°C to which 3 parts of nitre can be carried on continuously.
Pre-pickling the parts in a mineral acid,e.g. hydrochloric acid, deepens the colour.
By increasing the concentration of the lye and the amount of nitre,and heating to 180-200°C polished iron parts can be coloured in about 5 minutes.
After removing from the bath,rinse with water,then with lime solvent,e.g. diluted acetic acid, to get rid of adhering lime, then several times with hot water,dry and finish with linseed oil or lacquer.

The advantage of the process is complete preservation of the surface and polish by the lime addition.
The oxide coating does not peel off.

It is found that a freshly prepared bath does not start and act so easily and thoroughly as one containing reduction products of oxidants used, such as nitre,potassium permanganate,potassium or sodium dichromate,etc.,this is,nitrite,manganite,chromate,etc.

If small quantities of such reduction products are added from the start,the colouring action sets in at once and produces deeper shades,an effect which can be further reinforced by the addition of small quantities of an iron salt,e.g. ferric nitrate.

I hope this helps.

[Charles Owlen Picket]

Thank you; it does help!

Often in receivers made of higher nickel content, there appears to be a "purple" hue to the blue. With those techniques mentioned above - I am assuming there would be a difference in hue and color depending on the alloy, etc...(?)
- Having tried these techniques what were the result & your observations regarding coloration and strength/resistence to color removal?

[Gunjack]

The color does not fade.
The strength/resistance to color removal is excellent.
Even after years.
Even when I gave it a good work over with steel wool.
This process produces one of the deepest black colors even for different alloys I've tried.
The coloration took place in only 10 minutes.
Then I had a pitch black color on the pieces.
It is easy to check the color by moving the pieces from the blueing tank to a bucket of water where you can check the color.
If there not black enough you can put them back in the tank to get a darker color.
But do not tough them by hand.
If there are spots that do not color well you can rub them with a cotton swab using only the blueing mixture on the swab.

And the color does vary from alloy to alloy...
You can even color some stainless steel but you will not get the deepest black you might want.
The stainless will only become a dark grey colored piece.
This was the best process I've found after I did about a year of trail and error research.



If you want to know more, please let me know.

[Genocyde]

I'm a TIG weldor by trade, and do alot of hobby blacksmithing. Salts are commonly used in the heat treating processes, although I am not aware of any arsenic salts used in the process. Potassium nitrate the most common used. It is possible I suppose, but the thought of any residual arsenic being in the alloy is ridiculous.


Here is a very good source of information on the web.

http://www.anvilfire.com/

[Charles Owlen Picket]

I truly appreciate this input. I am going to try out some of this material on various ferris alloys and post my experiments. The fact that SS is acted upon by the above technique is fantastic.

[Gunjack]

The greater the amount of iron in the stainless steel, the darker the color.
You can check with a magnet.

[Bugger]

That would probably be due to "passivation", by formation of a layer of Fe3O4 (ferrous ferrite, magnetite), in which some of the Fe may be replaced by Ni(II), Ni(III), or Cr(II), or Cr(III) . Unlike Fe2O3 and FeO(OH), the common components of rust on iron, which is porous and flaky and non-adhesive, Fe3O4 is impervious, not admitting further oxygen to react with the Fe.