Etches - Interesting Observations

Dave Rishar

Dave Rishar

Joined
Oct 25, 2004
Messages
3,178
I had the opportunity to do some etching this morning. Some of it turned out quite interesting. I made sure to do a few models that most people don't see etches of - namely, a Karka Special, the Tez Darr, and a WWII-issue khuk from AC.

This morning's etches were done with Klean-Strip Rust Remover. It works very quickly (<1 minute) and leaves a nice contrast. It's quite dangerous and puts off some nasty fumes so if anyone is thinking of trying it, try it outdoors first.

Once again, I'm only posting links to pictures and not inserting them directly into the post. These are high resolution, so feel free to zoom in.

First up: 16 inch Karka Special. Note that the hardened zone extends completely to the tip and is quite wide. The pattern is just about identical on the other side. I'm still not planning on thrashing it but it looks like it would hold up to such a thrashing quite well.

Next: the Tez Darr. Honestly I wasn't expecting a hardened zone, but there it is. While it's quite small and limited pretty much to the tip, I don't think I could draw a line that straight freehand. It's pretty much the same on the other side.

A 12 inch Sirupati follows. I tried two different vinegar etches and one mustard etch with little success - one side came out fine but the other seemed defective. The rust remover did the job and it turned out that both sides are fine after all.

Here's an Everest Katana. This one was done with multiple vinegar etch/ polishing cycles - 3, if I recall correctly. The temper line is much more subtle because of this. The tip is just off camera to the left, the handle to the right; the majority of the edge is hardened. Looks good.

In light of the recent seax threads, here's mine. The hardened zone starts about midpoint and continues nearly to the tip.

AK Bowie. Not much else to say.

Here's another oddball: WWII-era khuk purchased from Atlanta Cutlery. I was interested in seeing whether there was a hardened zone or not and, if so, how the pattern might have differed from the HI khuks I have. I'll let you draw your own conclusions. It's a bit hard to see because there's a nasty grinding mark right in the middle of it (not put there by me!) but it's still fairly visible and is located right on the belly. Not bad. The markings on it are "SA HW45" - whatever that means - and it looks as if there was another marking that was obliterated at some time in the past. I'll put a pic of the markings up at another time.

This concerns me - my 20" AK. Here's another view from further away. The zone seems to be in the right place but looks a little small to me - in fact, it's by far the smallest of any of the hardened zones I've seen on any of my HI khuks. Is this normal?

And now, for the weird stuff:

This was the fourth etching of the 20" AK; the first two were vinegar and the third was rust remover. No temper line showed up until the third time; I did a fourth etch because I figured that the hardened zone must be larger and something had gone wrong with the etch.

I have not been able to successfully etch my kagas katne. Vinegar, mustard, and rust remover have all been tried several times. I didn't notice a difference between the edge and the spine with a file but I'm not experienced in judging hardness this way and I may just be missing it. It does hold an edge well.

The Manjushree Sword was a failure. The rust remover attacked it so aggressively that I aborted. Is it a different steel? I spent 20 minutes or so polishing it and it's almost back to normal. The same thing happened with the 20" AK the first time it met rust remover - very aggressive etching with heavy black speckling that polished off easily. I will probably try etching it one more time with rust remover; after that, I'll use vinegar or something else less aggressive. I'm very interesting in seeing how this was hardened.

I'd almost written off the Kerambit until I tried the rust remover. It does indeed have a temper line - it starts just a millimeter or two shy of the tip and runs about an inch back. Even using the rust remover it's so subtle that it wouldn't show up in pictures.

Edit: pics are now down. If there's one you missed that you want, let me know via email.
 
Bri in Chi said:
Looks very interesting. Where is the stuff available?
Click to expand...

Klean-Strip ought to be at any hardware store. I've got my own ritual I use for it. Email me if you want the specifics but it's probably more superstition than anything.

I reckon you know where to find the khuks. ;)

The 20" AK's hardened zone is still bothering me. I mean, the thing worked fine before and should work fine after, but now I'm wondering; it did pick up more edge damage on the laptop than I'd expected but I'd written it off to the extra weight. It certainly wasn't serious - one pass with the belt sander on each side erased everything.

One thing I should add is that I've tried etching a few kardas with no results, but I wasn't expecting any zone hardening there in the first place - it was simply to check all the angles.
 
Satori, you REALLY do your homework.

That was a great learning experience.

When I rebuild my shop, all the HI's are going in for a look-see like that.


Ad Astra
 
Update:

I've tried three rust remover etches, one vinegar etch, and one mustard etch on the Manjushree and have been unable to spot a temper line. At this point I don't believe that it's zone hardened but the jury's still out. I'm fairly sure that the steel is a bit different than the norm (it etches very differently).

Still no luck on the KK. I'll try mustard next.

No pic yet but I'll have to put one up of the Tulwar. This is the wildest one I've seen so far...I won't try to describe it, I'll just have to take a picture. I don't know what to make of it.

Napoleon Sword is showing a faint (too faint to photograph) temper line by the looks of it, starting about halfway up the blade and running just about to the tip. If this is indeed the hardened zone, Bura was doing his homework.

The 30" Sirupati isn't photographing well - I'll need to do another etch/polish cycle or two. The hardened zone is massive, running more than half the blade, and has a few waves to it.

Overall, the comparisons between the different models (and manufacturers) was interesting. I've noticed that with heavy use and multiple sharpenings, one gets a pretty good idea where the hardened zone is just by the edge condition after some chopping. Even though it was a PITA, I'm glad that I etched all of this stuff. Some of it (Tez Darr, 20" AK, Manjushree) were quite surprising.
 
You really should consider investing in some ferric chloride. Its about $5 a bottle at Radio Shack. Believe me, its much nicer than anything you can do with mustard and rust remover. You'll be able to see the grain structure of the steel and see now everything runs, its really beautiful. You could even make an etchant container out of PVC pipe, which would make etching your swords a snap.
 
I've got a bottle or two kicking around here...never tried it for etching steel but I'll give it a shot.

Forgot to add: same deal as for vinegar with the ferric chloride? Hot steel, hot etchant, kinda paint it on?
 
My experience with ferric chloride is this:

Completely clean and warm the blade in running hot water and dish soap.

Dunk the blade into, or wipe on a mixture of 1/4 ferric chloride to water. Add the acid to water, not vice versa. The 1/4 mixture is muh clearer than straight ferric chloride.

Let it sit for a few seconds, neutralize with windex, then repeat as desired, starting with the warming/washing step.

You can polish with 2000 grit sandpaper or white rouge between dunkings too.
 
Satori said:
I've got a bottle or two kicking around here...never tried it for etching steel but I'll give it a shot.

Forgot to add: same deal as for vinegar with the ferric chloride? Hot steel, hot etchant, kinda paint it on?
Click to expand...
Satori try adding a few drops of dish soap too the ferric chloride/water mix. Dean says it enables the etchant to cover better. You might try reading Deans tips thread, lots of different kinds of info there including etching. I think it is still stickied at the top of the main forum page.:D
 
Ferric chloride is nice stuff to etch with. I do not get problems with it causing rust or speckling. It doesn't stink either, so you can work indoors. It's probably not good for you, but when some got on my skin all it did was stain it slightly.

I've tried vinegar and it does not work very quickly, it seems.

Some people have a setup with two PVC pipes. One is filled with the etchant, the other with a neutralizer. Here is some advice from Don Fogg's website: http://www.dfoggknives.com/etching.htm For big knives, I just wipe it with a ferric chloride soaked towel.

Also, Satori, why don't you check the hardness on the 20" AK with a file? After I saw that thing chop apart a computer, I would expect that it should be hardened better than that.
 
Hot dish soap water, "Everclear" rinse, etchant, neutralize...buff. Dan hasa final step...forget what it is.

It looks like the Tez Darr was simply edge dipped...not poured.


.
 
Good input...thanks, guys.

The purpose of this whole exercise was just to get an idea of where, what size, and what configuration the hardened zones were on various models and how they compared with one another. These finishes will either get worn or polished off eventually and will probably not be replaced.

This ferric chloride leaves a very attractive finish but it is a lot of work - probably not appropriate for what I was doing, but it's starting to look pretty good on my 20" Siru so I'll take it to completion. On a related note, the kagas katne has a hardened zone - one dunk in the chloride revealed it. Outstanding.

On a not-so-good note, still no sign of a hardened zone on the Manjushree.

I took a file to the 20" AK and it confirmed the etch's results but I'll say again that I'm not too good at reading hardness with a file and I could be wrong. Taken together with the etch, I think that the hardened area is indeed that small.

Such are the joys of etching - the perfectly good khuk of yesterday becomes the questionable wallhanger of today. ;)
 
You know Satori...considering the purpose of that AK...and *not* trying to be ugly or anything...I believe that Bill would replace it for you. Mistakes *do* happen, we've seen that.

Just a thought...

.
 
Now why do you have to go and be nasty about it? ;) I'll take this as an answer to my question about whether this is normal or not.

I'd considered sending an email, but for three things:

1. It seems to work fine.
2. I wasn't sure what the hardened zone on an AK was supposed to look like.
3. UB has enough on his mind already.

It's not a safety issue regardless; I'll give it another good thrashing and see how it holds up. The thing did handle a laptop, after all...
 
Satori, I have a WWII with a smallish looking hardened part, much like yours. Its a great blade, chops wonderfully, and holds a great edge. I wouldn't worry too much about it.

Think of it as less likely to snap in half. :) ;) .
 
I'm not expecting any problems.

By the way, Jeb, I did three etch cycles on the 20" Siru and it's gorgeous. It's a PITA but worth it. I'll have to do a few more to see just what I can uncover. Thanks for the advice on that.
 
Can you make out the grain structure?

I love looking at the grain structure. You can see some nice transitions. I guess these are the sections of martensite, tempered martensite, and pearlite. I would compare it to staring at a lava lamp.
 
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