Don't do this, and question

Eikerværing

Eikerværing

Joined
May 30, 2002
Messages
374
WW2 16,5 inch

Used it to chop some trees in the forest.

Came home with it full of sap.

Tried to scrub it clean under running water. Tried soap and sponge. Didn't work.

Found a bottle of something in the closet. The label said:
"Bathroom & shower
Efficient and mild"

Sprayed that on the entire blade.

Suddenly noticing strong burning smell from that stuff. Kind of stinging in my nose. Bad I thought, very bad.

Looking at the blade in front of me as it started shifting colour or something. Looked as if rust formed with hyperspeed.

Small amount of panic.

Put under spring in lots of hot water. Scrubbing scrubbing scrubbing.



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Now I have a blade that looks as if someone left it all full of blood and left it drying up for about a year. Not red, but rusty brown. It really looks as if the blade has been dipped in some kind of liquid and massive drops have been running down on it to form tracks.

Oh, and the hardening of the edge shows now. I can see that it stops before the point and the bend. The hardening is exactly 0,9 mm deep into the edge.


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I am a little bit clueless about the temperature regimes during heat treatment. Did I destroy or change the properties of the blade by holding it for a considerable time under hot water? The entire blade felt hot afterwards, somewhat hotter than the edge usually becomes during chopping trees. But since I can still see the hardening then it must still be there, or what? Or could the hardness on the edge now be lesser than before or something?

Can I undo the new bloodrusty colouration pattern?

It says on the bottle of cleaning agent that it contains less than 5% anionic tenside. Should not be used on "marmor" which is that natural rock that the ancient Greeks used a lot. It doesn't say anything more about the chemical compounds.
 
It looks like you just etched the surface of the blade. It shouldn't have changed the temper. At least without a lot more heat. Sort of the same thing as the folks etching the blade with mustard in some of the current threads. You can remove the new finish with some fine steel wool and give it a dull satin finish. Unless you want to repolish it. For a knife you are going to use outside a lot, the satin finish is more easily maintained.
 
5160 tempered at 350F still retains a hardness of 59RC or so(depending on complete heat treat). Unless you run your water heater a LOT hotter than any normal human does, you didn't come close to this. Don't worrya bout the hot water.
 
Eikerværing, take a deep breath and relax.
As I'm sure the others will tell you, you can't hurt the temper on a finished knife by putting it in hot tap water like you did. The temper line is showing because of something acidic in the cleaning spray you used. Cover the khukuri with oil while you figure out what you're going to do next. Rub the oil in well.

There have been several threads about putting an intentional patina on knife blades, the guys are going to want to see pictures of your knife.

Is the temper line a consistant .9mm? I'm impressed if it is because the kamis pour water on the hot (hotter than tap water) blade to temper it. There are pictures on the FAQ page.


Just stay calm, it's a tough knife and it will recover.
 
Ok thanks folks.

I know that fire is a lot hotter than hot water. But I had to ask just to make sure.

The temper line is varying from 0,8 to 0,9 mm, mostly it is 0,9 mmm. It is quite amazing really.

It has this short transitional zone with a kind of brown/yellow colour between hardened zone and normal steel. That zone is 1 mm.

1 cm away from the cutting edge you have normal steel quality.

That was for a 16,5 inch WW2. I don't know if it would be different on the other models.

Picture? I don't have a digital camera, and this is going to be a picture where I have to get the correct light conditions. I could really use a digital one for this so I could make lots of experimental pics. I will go and ask in the photoshop tomorrow if I can have a single digital picture taken there.
 
Hold on a second. There might be more zones before that zone.

This is a bit hard to see.

I think there is one kind of purple-blue zone there also, beneath the transitional zone. It ranges from 1 to 2 mm thick, but mostly it is 1 mm.
 
"5% anionic tenside"



= detergent, sufactant, bearing a negatively charged polar group.

Typically a sulfate substituted with a long alkyl chain. Used in many soaps, shampoos, cleaning formulations.

Some other ingredient else etched the khuk, I think. If the stuff makes the dark mold or mildew that often occurs in bathrooms "disappear" (to quite the advertising) I'd bet that there is some bleach (hypochlorite) or peroxide in it. Those are both oxidants which would etch and corrode steel.

Oil the khuk, relax and have a beer.

Congratulations, you've found an easy fast way to etch the knife and visualize the temper line. Some people here have tried a bunch of ways to do this with varying levels of sucess.

You might try gently polishing the blade with oil and and the finest steel wool you can find to even out the etch. You may like the result.

A good metal polish will probably remove the color if you don't like it.
 
Marmor is marble----"A metamorphic rock of made of calcium carbonate. Marble forms from limestone by metamorphic recrystallization. "

Probably the cleaning mixture contains an acid if there's a warning
to not use on marble, which would be etched-->roughened by this solution.

As quick as the blade got etched, I'd guess a pretty strong acid.
Or one that works particularly quickly on iron.

Here's a tidbit I found that mentions cleaning marble:
"Acid--Spills from acidic foods such as citrus drinks, carbonated beverages, wine, tomatoes, etc…will also etch marble surfaces. Some cleaning products that may contain acid will also cause etch marks.
Alkaline--Chemicals or solutions that contain high alkaline or bleach can be absorbed by marble, causing the smooth surface to break down, leaving it rough and making it loose its shine. "

As everyone has mentioned, don't worry.

BTW, in the future, remember that hot water speeds up chemical reactions.

See if you can find a pine oil or orange oil based cleaner next time.
Or spray window cleaner maybe.

Here's a good thread with lots of good suggestions:
http://www.bladeforums.com/forums/showthread.php?s=&threadid=205642&highlight=clean+pine

And here a previous HI thread:
http://www.bladeforums.com/forums/showthread.php?s=&threadid=225231&highlight=clean+pine

It's interesting and educational to see the zones of hardening
along the edge of the blade.

How about a report on the chopping.....?
 
As the kamis used to say, "who cares how it looks if it works?"


Bill?

Oddly enough, that's what most American women say about their second husbands!:D
 
No pictures I am sorry. Couldn't get any in the photoshop at a reasonable price.

I think I am going to leave the khukuri as it is. It works and that is all I need.

Today it looks a bit different. Last night I only looked at it in artificial light. In daylight it doesn't look rusty at all and it still has the mirror finish (a bit foggy though), but you can see that some kind of liquid has been flowing over it and made an impact on it.

The hardened zone is visible.



Originally posted by firkin
Some other ingredient else etched the khuk, I think. If the stuff makes the dark mold or mildew that often occurs in bathrooms "disappear" (to quite the advertising) I'd bet that there is some bleach (hypochlorite) or peroxide in it. Those are both oxidants which would etch and corrode steel.
Click to expand...

Firkin, it says that the fluid is activated by the spraying action. By spraying I mean pulling a trigger with your finger so that you produce a shower by a manual pumping mechanism. This covers the object with white foam and liquid.

Originally posted by firkin

Congratulations, you've found an easy fast way to etch the knife and visualize the temper line. Some people here have tried a bunch of ways to do this with varying levels of sucess.
Click to expand...

That's funny actually.

But before anyone tries the same I must warn to not use any spray bottle that produces a foam. You see that in the places where I got a lot of foam I can now see foam/bubble imprints on the blade, which is not very pretty.
 
"I think I am going to leave the khukuri as it is. It works and that is all I need."

Score one for the dust bunnies.


"Firkin, it says that the fluid is activated by the spraying action. By spraying I mean pulling a trigger with your finger so that you produce a shower by a manual pumping mechanism. This covers the object with white foam and liquid."

Yep that's those anionic tensides at work. Of course anyone who has lathered up with soap is familiar with the phenomenon. Why that is supposed to be impressive, I dunno. The fact that this is often accompanied by the implication that the foam or bubbles somehow "does all the work", that scrubbing is not needed, supports the idea that there is something stronger in such concoctions. The price that such products mysteriously command, at least here, suggests that vinegar, citrus juice, ferric chloride solution (circuit-board etchant) may be less expensive things to experiment with. Often people add a tiny ammount of dish-soap to these things to help wetting of the blade.
 
Very interesting discovery.

Three questions:

1) If the super hardened zone on the sweet spot on a khukuri is only 0.9-1 millimeter on the edge, does that mean that if the edge chips or rolls over (seems to happen right on that 1 mm edge, that the khuk loses a bit of that super hardened edge?

2) Does that also mean that sharpening one's khuk too aggressively past 1 mm will take off the super hardened edge, too?

3) Could that be why the chakma is an integral part of the Khukuri - the Nepalese tend to use the chakma to sharpen/straighten the edge rather than grinding it down?

Some comments would be greatly appreciated.

Thanks in advance.
 
Oh sh*t!

I have given all the wrong measures!

Not 0,9 mm but 0,9 cm!!!

That changes the perspectives a lot The Big Kahuna!

You won't have any problems with any rolled over edge, too much sharpening, and you can perfectly safe grind it down a lot.



Now let's look at those figures I gave again.

The temper line is varying from 0,8 to 0,9 cm, mostly it is 0,9 cm.

The transitional zone with a kind of brown/yellow colour between hardened zone and normal steel was correctly given to be 1 mm.

The other purple-blue zone, beneath the transitional zone which ranges from 1 to 2 mm thick, but mostly it is 1 mm was also correctly given to be in mm.

So the hardening bites deep into the blade!

Sorry about messing up with the cm and the mm. It was late and I was tired.


++++++++++


Edited to add:

Now that I take closer look at it again I think I am starting to see even more zones inside that 0,9 cm which I first described as one uniform zone, or possibly the light conditions are joking with me. Hard to separate them, I need a microscope or something.
 
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