Patina; it's not just for looks....

M

MacTech

Joined
Jan 7, 2006
Messages
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Allow me to relate a pseudo-horror story, a story of the misadventure of an Opinel 6 that tried running away from home, and what we both learned in the process....

Set the WayBack Machine to a couple years ago, a humid Friday afternoon in seacoastal Maine, with thunderstorms rumbling on the horizon....

MacTech had just arrived back home, and was walking from his car, across the lawn, to the house, as he walked across the lawn, his trusty, nicely patina'd Opinel 6 slipped out a hole in the bottom of his pocket, and landed silently on the soft grass....

MacTech didn't hear or feel the #6 drop, due to the other stuff in his pockets, he walked away, with the knife lounging casually on the grass

At first, the Opinel relished its new-found freedom from PocketPrison, the temperature was comfortable, the lawn was soft...
.. .Then he heard it the worrying sound of thunder....
(iPhone is being temperamental, I'll continue in the next post...
 
....that evening, the skies opened up, in a torrential downpour, saturating the #6, as it laid blade spine down in the grass, the #6 was drowning....

The downpour continued all weekend, and MacTech stayed inside the whole time, oblivious to the knife's plight, unable to hear it cry, as corrosion started to form....

Monday morning, MacTech was walking out to work, when a glint caught his eye, looking down, he saw the #6, his heart sank as he realized it sat out in the rain for TWO DAYS, he tried to open the blade, but the wood had swelled and jammed the blade closed....

As he pocketed the knife, planning to open it at work and check the damage, he noticed the hole in his pocket, and redistributed the contents to the other pockets....

At work, he grabbed a pair of pliers and pulled the blade open...

RUST! Horrible red rust all over the blade, he was sure the blade was ruined, but grabbed a maroon scotchbrite pad and went to work....

Once the rust, and remaining patina had been scrubbed off, he was amazed to see that the blade had suffered NO damage, no pitting, the red rust was merely surface rust, the patina had protected the knife from two days of rain!

Amazing stuff, that patina...
 
Thanks for posting this. I'm fairly careful with my knives, but I recognize that sooner or later, it's quite possible one might go for an unexpected layover somewhere (even outside). I hope I'm as fortunate with removing the rust as MacTech was.
 
Great report, Mac.:thumb up:

While the patina will provide some protection, I'm really amazed that in two days there was no pitting, however light. But carbon steel blades have been providing cutting service to man for a couple thousand years now, and somehow all those old Vikings sailing the sea in open boats, and Conquistadors sailing in slow galleons and spending many months and even years in Mexican and South American jungles with carbon steel rapiers, I can only wonder if the rust boogyman is highly exaggerated?

I remember my boss at the last job I had before retiring, came to work on a Monday morning, and about an hour into the day, he couldn't find his old TL-29. We looked all one rthe shop, but no go. It was the hight of summer, and that week it was one thunder storm after another. We were getting off Friday afternoon, and Paul mentioned that he was going to go buy another pocket knife over the weekend.

Monday morning he comes in with his old Camillis TL-29, a bit more stained and darkened. He went to go do a little bit of work on the farm Saturday morning before going to shop with his wife. There on the seat of the John Deer tractor was his TL-29 where he'd left it after working on the tractor the past Sunday. It has sat out in a week heavy with summer thunderstorms, and just had a bit of rust on it. Some Scotch Bright and a little gun oil, and it was good to go.

Go away, boogyman rust, we have patina!
 
It's amazing that anyone ever went to the trouble of inventing stainless steel, when all they needed to do was put a patina on carbon steel and it would never rust.
 
That is encouraging! Maybe I will go look again for the Ruana I left at a gutpile in 1972.
 
I was stunned when all the corrosion simply scotchbrited right off, I still use that very #6 to this day, and, in fact due to its trial by fire, it's become my hard use knife

I'm looking at the blade right now, and can find no evidence of pitting, admittedly the patina it has now is far heavier than when it had its little escape

I'm almost tempted to punch out the pivot pin and suspend the blade only in a water mist, or maybe just rest it over my open top aquarium, just to see how long it takes for pitting on a heavily patina'd blade

But I can't bring myself to deliberately abuse a knife...
 
Warning, skeptical devils advocate rant ahead

MacTech said:
grabbed a pair of pliers and pulled the blade open...

RUST! Horrible red rust all over the blade…

the red rust was merely surface rust, the patina had protected the knife from two days of rain!

Amazing stuff, that patina...
Click to expand...

wait a minute! The red rust formed, the patina did not prevent red rust. The fact you took the rust off so quickly, prevented it from pitting the blade. The Patina did nothing.

jackknife said:
There on the seat of the John Deer tractor was his TL-29 where he'd left it after working on the tractor the past Sunday. It has sat out in a week heavy with summer thunderstorms, and just had a bit of rust on it. Some Scotch Bright and a little gun oil, and it was good to go.
Click to expand...

according to knarfeng, patina is porous, so it will hold oil better than a bare blade. I would venture the blade on the tractor survived because it was oiled, not due to a dry patina..

jc57 said:
It's amazing that anyone ever went to the trouble of inventing stainless steel, when all they needed to do was put a patina on carbon steel and it would never rust.
Click to expand...

wait! both knives left in the rain rusted! they both had patina, and they still rusted.

MacTech said:
I was stunned when all the corrosion simply scotchbrited right off...

I'm looking at the blade right now, and can find no evidence of pitting.
Click to expand...

So, your conclusion seems to be that patina does not prevent rust, but it prevents pitting!

I call wishful thinking. In both examples, Red Rust was not prevented by patina. Instead you are changing the criteria to suggest that patina prevented pitting.. That makes no sense to me. Red Rust formed, that was not prevented by patina. I propose that lack of pitting is not a feature of patina. Lack of time is what I think prevented pitting.

imo, it is an urban myth that patina prevents rust. Both examples above demonstrate patina did not prevent red rust.. Red rust can be prevented by scotchbrighting your blade daily. That will also prevent pitting.

Science based testing Challenge:
Obtain 2 new Opinels. Stick one in a potato overnight, but do not oil the blades. Then put both in the rain for 2 days, and get back to us to report that Red Rust only formed on the unPotato knife.

If you want to use pitting as a criteria, don't clean the blades after 2 days, instead leave the rust alone, wait 30 days, then check for pitting. If the Potato blade does not pit, and the unPotato blade does, I will eat.. a Potato.
 
jon_slider said:
Science based testing Challenge:
Obtain 2 new Opinels. Stick one in a potato overnight, but do not oil the blades. Then put both in the rain for 2 days, and get back to us to report that Red Rust only formed on the unPotato knife.
Click to expand...
That sounds easy to do. If it wasn't done before you can even make a scientific paper out of it with very little effort. At the very least it would be an awesome high school science project.
Prior to potato and unpotato I would rub both blades with ethanol to remove fingerprints and factory oils. Same before the exposure to the elements. Scientific would be same amounts of Water on both blades. 2 times spray bottle some water on them.
Keep the whole experiment at a known and constant temp, so it is repeatable for others or you, in case you want to test different patinas, steels or with oil later and compare to previous results.
 
Patina is a form of oxidation as is rust as is gun blue or browning. Steel is porous and unless it has a coating or rust inhibitor in the pores, it will rust. A hunting knife I had for forty years had a nice patina. I kept it cleaned and oiled. I did not scotchbrite or steel wool the blade. But washed and dried then oiled it after use. If I left it out in the rain or left blood on the knife for days, it would form spots of powdery rust which could be wiped off with a cloth. Pitting would take longer or the presence of something either acidic or caustic.

I get the impression that people today are needlessly afraid of carbon steel knives rusting and consider it a defect, thus the mass migration to chrome-like stainless bladed knives. Carbon steel knives, like old fashioned 1095 and it's kin, do take a bit of care, but not so much. I do use a stainless premium stockman in my work because of exposure to salt and chemicals, but for most normal use, even outdoor sporting like camping, hunting and fishing, I use carbon steel knives and have no problem with them rusting. I just learned growing up not to store my knives wet or dirty. And yes, a good thick overall patina will hold protective oil better than a freshly "buffed to mint" blade, at least in my experience. It is how a well seasoned cast iron skillet can have a surface almost as non-stick, non-rust as teflon.
 
It's not for looks at all. Patina just is. It's only recently that people have started forcing patinas for appearance's sake.

- Christian
 
First I'll say I'm a fan of patina and do beleive it helps prevent red rust. But just a little. I think Jon is correct and patina will not stop red rust or pitting. In fact I'm a little surprised that red rust formed so quickly on the knife being outside for only 2 days in the rain.
 
Surface rust is fast. Our HK G3 army rifles rusted within 24h in the rain. No clue what steel that was. For sure no stainless :D
Anyways, some oil and a soft cloth was enough to remove it.
 
db said:
First I'll say I'm a fan of patina and do beleive it helps prevent red rust. But just a little. I think Jon is correct and patina will not stop red rust or pitting. In fact I'm a little surprised that red rust formed so quickly on the knife being outside for only 2 days in the rain.
Click to expand...

Rain is often acidic, exacerbating the corrosive effects of the hydrogen and oxygen in the water. This is why acidic foods will put a patina on a blade.
 
jon_slider said:
Warning, skeptical devils advocate rant ahead



wait a minute! The red rust formed, the patina did not prevent red rust. The fact you took the rust off so quickly, prevented it from pitting the blade. The Patina did nothing.



according to knarfeng, patina is porous, so it will hold oil better than a bare blade. I would venture the blade on the tractor survived because it was oiled, not due to a dry patina..



wait! both knives left in the rain rusted! they both had patina, and they still rusted.



So, your conclusion seems to be that patina does not prevent rust, but it prevents pitting!

I call wishful thinking. In both examples, Red Rust was not prevented by patina. Instead you are changing the criteria to suggest that patina prevented pitting.. That makes no sense to me. Red Rust formed, that was not prevented by patina. I propose that lack of pitting is not a feature of patina. Lack of time is what I think prevented pitting.

imo, it is an urban myth that patina prevents rust. Both examples above demonstrate patina did not prevent red rust.. Red rust can be prevented by scotchbrighting your blade daily. That will also prevent pitting.

Science based testing Challenge:
Obtain 2 new Opinels. Stick one in a potato overnight, but do not oil the blades. Then put both in the rain for 2 days, and get back to us to report that Red Rust only formed on the unPotato knife.

If you want to use pitting as a criteria, don't clean the blades after 2 days, instead leave the rust alone, wait 30 days, then check for pitting. If the Potato blade does not pit, and the unPotato blade does, I will eat.. a Potato.
Click to expand...

I think he's trying to get a potato here folks... :)

Pitting takes TIME. Red rust will quickly start as a haze. It will build and deepen if left alone. Over time it "eats" down into the steel and hence pits develop.

I just give it a quick wipe on my tshirt or jeans after each use and let it alone. It ages as it will depending on use, humidity, exposure to chemicals or salts, etc. i dont fret over it, just let time do it's work.
 
hows the opening/closing now.i recently left mine on the bait table for four days on a boat on saltwater.at the end it was covered in scales,brine and stench.resultant stiffness an thick lumps of rust were alm easily fixed with a wash and brush up and a smear of oil.definitely agree with the time factor theory.i just cleaned up an old ulster scout knife that had rust and pitting because it hasnt been cleaned for years.ok now an nice patina.
loved the story mac.
 
Patina is a different rust than red rust. The oxidation is different.
Now will water turn the black rust into red rust or leave it black? If it stays black then the black rust should be a protection against red rust. Of course only if water can not penetrate the black rust and form red rust underneath the patina. Codger mentioned its porous so yeah....
 
This is my blade after a week at work , no care or attention , it started out as a clean fresh blade .

I must check it for rust before I put it back in the cupboard .


Ken
 
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