Natural patina

Rick Baum · May 7, 2003

Is there a difference between a natural patina and one that is artificially induced via etching with some sort of acid based solution? Aren't both just oxides that have formed on the surface of the steel?

If an old knife had been differentially hardened would a natural patina show the temperline? Just curious.

Rick

Mike Hull · May 7, 2003

According to antique "experts", a natural patina cannot be duplicated with chemicals. I guess they can come close, but the results are easy to spot.

This is something that has always bothered me. If you have nice things in your house, copper lamps etc, and you bought them new, would any good housekeeper let them tarnish? I doubt it. People kept their stuff as nice as possible. But antique dealers say that if you take the rust off, or polish away the "patina" on brass, or copper, you've destroyed 2/3 of the value. But on silver, it's just the opposite, that must be polished.

firkin · May 7, 2003

That's "collecters" for ya.

Whatever is the most unlikely to be found, is worth the most. Anything else is secondary.

Will52100 · May 8, 2003

I've seen a couple of knives aged by wipeing down with lime juice, and I've acidently done it by cutting a hot juicy steak, and have heard not to long ago about canalope blueing a blade.

I supose it depends on the steel whether the harding line would show well or not, and also the type of patina. I beleive that when you etch a blade, your eating away at the steel and the hard edge gets eaten away at a diferent rate than the back.

Jason Cutter · May 8, 2003

Different materials produce different effects. I find that meats produce a nice deep blue colour, while acidic fruits give a more grey colour. Whats nice is a combination of those hues on the blade. I find that because the tarnish or patina is such a gentle process comapred to say - ferric chloride, it may not show a temper line.

My reason is this - 10-xx series steels that show those marked hardening lines will already show them with or without etching - it just gets a bit clearer with tarnishing. Steels like O-1 and 52100 may not show the temper lines until the knife has been used a lot, tarnished a lot and then cleaned a lot. This starts to act like the quick etching and final finishing process we do with ferric chloride and other etchants.

Not sure if this makes sense. Just something I noticed on my kitchen knives. Jason.

RHINOKNIVES · May 8, 2003

i don't mean to eat

that stuff will make your ass burn for a week!

i mean to patina your blades

chisel · May 8, 2003

how true that is Laurence!

Rick Baum · May 8, 2003

RHINOKNIVES, I've heard too many stories about IG's HT relish eating holes clean through the blade when left on too long. I'm staying clear of that stuff

Will, I've noticed the same blue effect on some of my O-1 blades when I break them in on a steak. I tried lemon juice also, things turned dark grey on me. I think you're right about the steel making a difference. The 10XX series steels seem to show a temper line more readily than some of the others.

Jason,

10-xx series steels that show those marked hardening lines will already show them with or without etching - it just gets a bit clearer with tarnishing.

Since old blades were probably made with very simple steels like the 10XX series steels, maybe the transition lines would be visible if the blade was differentially hardened???

Did the japanese blades do any kind of etching treatment to reveal the hammon?

Rick

Dan Gray · May 8, 2003

this is one I did one sometime ago, made from O1
I got a big beef steak
and soaked the blade with the blood from it.
dabbing here and there from time to time with a damp cloth.
I use many thing on all type of steel.
supper was good that night too. you tell me if it looks old?

Coonskinner · May 9, 2003

I have tried all kinds of things to reproduce the kind of beautiful patina that carbon steel acquires over a period of time, and I have come to the conclusion that there ain't no shortcuts.

Yes, you can darken the blade and come close, but it doesn't look the same to me as a real patina that comes with time and use.

Ken Cox · May 9, 2003

The word patina has several meanings.

patina \pe-"te-ne, "pa-te-ne\ noun pl patinas \-nez\ or patinae \-'ne, -'ni\ [It, fr. L, shallow dish more at paten] (1748)
1 a : a usu. green film formed naturally on copper and bronze by long exposure or artificially (as by acids) and often valued aesthetically for its color
b : a surface appearance of something grown beautiful esp. with age or use
2 : an appearance or aura that is derived from association, habit, or established character
3 : a superficial covering or exterior
(C)1997, 1996 Zane Publishing, Inc. All rights reserved.

Many years ago I read an extensive article (possibly in American Rifle) about the German finish called browning.
This finish actually comes out different colors depending on the steel and the techniques used to produce it.
One sees it on some early Lugers, especially on the trigger, as a straw color, surprisingly golden in appearance.
In any event, the author referred to browning as a patina similar to what one might see on a farmer's frequently handled metal tools.

Browning requires considerable time and labor and so one does not see it anymore except on the most frighteningly expensive firearms.
I understand it provides significantly greater resistance to the types of corrosion caused by humidity and body salts than does traditional hot blueing.

One method of browning requires a dedicated room (a closet will do) with a high level of humidity and a relatively cool temperature.
One places the metal part he wants to brown on an soft absorbent surface, like a towel.
Once or twice a day one should pick up the metal part, wipe it down vigorously with a clean cloth, and then lay it down with the formerly down side up.
I vaguely recall that one sparingly uses a fine, light oil initially, and attempts at each wiping to remove the oil.
I think this process takes 30 to 40 days.
At the end, the metal has no oil on it and it has assumed a golden straw color, or, if allowed to progress, a soft, deep brownish-gray color without any pitting or loss of surface smoothness.

I have read of a similar process in which the smith used a warm, humid room or even a box with a light bulb and a dish of water in it, and wiped the subject piece several times a day.
I think with heat one has to wipe the metal more often, and it may effect the color.

I think it would help to know what type of oil to use.
I think the thinnest and lightest available.

Apparently, the regular wiping prevents pitting and allows the steel to form a relatively deep layer of polished oxidation that eventually takes on somewhat of a protective function as well as striking aesthetic beauty.

I have an old shotgun of my grandfather's that has taken on this grey-brown color.
Because of neglect (mine) it also has some pitting.
Too bad.
Still, the surface of the metal where it has not pitted looks beautiful.

Mike Hull · May 9, 2003

Quote"
Many years ago I read an extensive article (possibly in American Rifle) about the German finish called browning.
This finish actually comes out different colors depending on the steel and the techniques used to produce it.
One sees it on some early Lugers, especially on the trigger, as a straw color, surprisingly golden in appearance.
In any event, the author referred to browning as a patina similar to what one might see on a farmer's frequently handled metal tools."

That straw, and also some reddish colors on the trigger, side plate, and sometimes safety on Lugers, was the result of different alloys in those particular parts. All the parts were blued the same amount of time. Later, either the alloying elements in those hard to blue parts was changed, or they worked out a better method of bluing. The same straw/reddish color happens in modern guns with high nickel content barrels and such, if not done properly . You have to immerse the parts with the solution at lower than normal temperatures, then increase slowly. Done this way, you should see no difference in color.

Wild Rose · May 9, 2003

Browning requires considerable time and labor and so one does not see it anymore except on the most frighteningly expensive firearms.

There are lots of different commercial browning solutions available including the ubiquitous Plum Brown from Birchwood Casey. Just heat the metal and wipe on the solution. Rub down with 4/0 steel wool. Repeat until you get the desired coverage/color. Kill with a good soap and water wash and then oil well
There are other cold browning solutions where you wipe it on and then hang and with these a high humidity atmosphere helps.
But there are no real mysteries to the finish - other than for a few commercial makers, every modern muzzleloader made today uses a brown finish just like the originals.

As for the experts I love watching Antiques Roadshow, and it always gives me a real laugh when one of those experts starts talking about something and you can tell they not sure about what they are talking about, but they'll bluff their way through. Recently one guy was pontificating about an Indian pipe and the bowl was attached to the stem wrong yet he never mentioned it. Apparently didn't have a clue. In another instance I have a good friend who does some of the most fantastic Indian reproduction work you have ever seen. On a recent visit to a major museum he noticed a piece that is listed as being from the 1880's, yet he recognized it as a piece he had made sometime in the 1980's. Seems that some unscrupulous collector had artificially aged it and then sold it as na original piece. When he tried to inform the museum people they got their nose all bent out of shape. He found out later they had paid a hefty 6 figure sum for the piece and weren't about to have their noses rubbed into the fact that they had been taken.

According to a chemist I discussed this a while back there is no real difference between a natural aged oxidation patina and one artificially produced at least on metal. They can tell what caused the oxidation, but if the oxidation was caused in both instances by a natural chemical reaction such as lemon juice there is apparently no real way to tell the difference. This is at least what I have been told anyway.

Mike Hull · May 9, 2003

Originally posted by Wild Rose

As for the experts I love watching Antiques Roadshow, and it always gives me a real laugh when one of those experts starts talking about something and you can tell they not sure about what they are talking about, but they'll bluff their way through. Recently one guy was pontificating about an Indian pipe and the bowl was attached to the stem wrong yet he never mentioned it. Apparently didn't have a clue. In another instance I have a good friend who does some of the most fantastic Indian reproduction work you have ever seen. On a recent visit to a major museum he noticed a piece that is listed as being from the 1880's, yet he recognized it as a piece he had made sometime in the 1980's. Seems that some unscrupulous collector had artificially aged it and then sold it as na original piece. When he tried to inform the museum people they got their nose all bent out of shape. He found out later they had paid a hefty 6 figure sum for the piece and weren't about to have their noses rubbed into the fact that they had been taken.

LOL!.......I agree about the roadshow.
A number of years ago when archaeologists discovered what they think are ancient batteries in the middle east, one tried gold plating some trinkets using one. It was a roaring success. There was a lot of speculation about this, and finally someone got an "unnamed" museum to allow them to test some artifacts. It turned out that about 90% of the "solid gold" items from the middle east were plated. No other museums would allow testing, and the story went away fast.

AKA Knife Knut · May 10, 2003

One method of browning requires a dedicated room (a closet will do) with a high level of humidity and a relatively cool temperature.

A nearly dead 'fridge perhaps?

Ed Fowler · May 11, 2003

My favorite gun shop just obtained one of the Lugers mentioned. Made before 1920 she looks like she was never out of the box. Un-fired and not even a round in the clip. The trigger and a few other parts look like they were gold plated. This was my first experience with old Luger patina and now I know what I saw thanks to Blade Forms.
I know someone is wondering, $970.00
Thanks Guys.