Jump to content
Sign in to follow this  
toddhill

hamon: dark or bright?

Recommended Posts

I was wondering if some of you would explain something about hamons. I've noticed that on some finished knives the edge below the hamon line is darker than the spine side. I notice this on western knives. However, on all the traditional Japanese knives the edge side is bright while the spine side is dark? What is the difference? I recently etched a 5160 blade and the edge came out dark while the spine above the hamon stayed bright. I don't get it. It seems that the dark is caused by the acid reacting with the softer steel so shouldn't it react more with the spine side since that is softer, making it darker than the edge side? Thanks for input. Todd

Share this post


Link to post
Share on other sites

Much has to do with the steel and then the finish. Your not going get a white frosted hamon on 5160. Quench line yes, not a traditional hamon tho.

Edited by sdcb27

Share this post


Link to post
Share on other sites

The difference between a dark hamon and a light body like this:

 

activityandhabuchi.jpg

 

And a light hamon and a dark body...like this:

 

closeup_F.jpg

 

...is a matter of cleaning off the oxides formed after you etch. When you apply an acid to the surface of the blade, it attacks the softer and harder areas of steel at different rates. It eats/rusts/oxidizes the steel surface and creates more contrast between hard and softer areas. For some reason unknown to me, an acid will attack the harder areas of steel more vigorously than it attacks the softer areas. When it does, it leaves behind a dark gray/black oxide that can be quite difficult to remove.

 

If you polish with Flitz, Pikal, or Simichrome metal polishes after etching you will remove all of the black oxides that color the hamon dark and end up with a frosty bright hamon like the one in the second picture. Most metal polishes contain some form of a reducing agent that lifts the black oxides right off.

 

If you etch the hamon and then just wash the blade with soap or Windex or whatever the hamon will stay dark. It has nothing to do with the type of steel and everything to do with the type of polish.

 

This is 5160 differentially heat treated:

 

geoffhamon_F.jpg

 

The hamon is light...not dark due to the polish and etch routine.

 

Brian

Share this post


Link to post
Share on other sites

Tempered martensite will show black oxide when etched, the unhardened will appear gray.

 

The traditional polishes did not etch, but used a combination of abrasive finishes to show off the hamon.

  • Like 1

Share this post


Link to post
Share on other sites

Thank you Brian and Don, your replies were very helpful. I will work the hamon some more and see what I can come up with. Loved the accompanying pics, Brian. Amazing how those traditional hamons come out with just polishing. Just blows me away. I am anxious to try some simpler carbon steels to see how they compare. That to me will really show how much it's the steel versus the polishing and etching. I learned something else on this blade. When I etched it, besides the hamon, a very dramatic line popped out starting from the lower tang notch and angling up through the blade to the spine. I am almost sure that this line marks where the steel didn't reach austenite temp. It doesn't affect the cutting edge at all, but it does interfere with the hamon a little. Next time I will be careful to get even the part close to the tang up to temp for quenching. Thanks again, Todd

Share this post


Link to post
Share on other sites

Alright, then! I've been fretting about not being able to get a hamon on my 5160 blades. Yesterday I took my latest, a broken-back sceax, up to a mirror finish and etched in a dilute solution of ferric chloride for half an hour, then rinsed and neutralised. I'd used an edge quench, differentially tempered with a torch. The results were great: dark edge, satinny grey spine. Just the look for this sort of knife! B)

Share this post


Link to post
Share on other sites

Isn't it all really about the way the different micro textures of the steel reflect light at different angles?

Share this post


Link to post
Share on other sites

Yeah, it is. If one polishes with stones (water stones and even some stone with oil) the scratch pattern left on the surface of the steel is different than if it is polished with abrasive papers. With stones, the difference between the hard and soft steel is a lot more apparent and you can easily see the different lustres of the different crystaline structures.

 

With abrasive papers one tends to smear the surface at the finer grits instead of opening the grain of the steel...the final scratch pattern will paper and oil seems to make seeing the hamon or difference in steel crystaline strucrure a lot harder to discern unless the light is just right. So, etching is the answer.

 

A light etch with weak acid seems to rough up the hard steel more than the soft steel and leaves the harder surfaces at a different texture than the soft steel structure. So after an etch the difference becomes a lot more apparent. With the right routine of etch and oxide removal the hamon can be seen across the room and be so vivid as to be almost gaudy.

 

But yeah, what we are seeing is the difference in crystaline structure of hard versus soft. In cool stuff with lots of activities you can see all kinds of stuff and all manner of different structures become apparent.

 

tantohamon_F.jpg

 

1086M tanto made by Howard Clark. I'm not sure about what all of the names are of the various lines, clouds and outlines but my guess is that there is probably one of every structure known to man with in the blade.

 

Looking at this blade in 1000 grit paper/oil polish I couldn't see anything but some faint shadows and a hint of a hardening line. The first etch made a little difference and then it all just popped out and blew my mind.

 

Brian

Share this post


Link to post
Share on other sites

I think most people try to go to a much finer grit with the paper polish than necessary. After dry sanding to 800 then etching I come back and remove the oxide with a fresh piece of 800 with lots of water and careful complete strokes parallel to the edge.I find this the best way to make that hamon pop out IMO.

Share this post


Link to post
Share on other sites

Brian - how did you polish that Clark blade? You did a really good job of bringing the activity out.

Share this post


Link to post
Share on other sites

I usually go to 1000 grit with oil on everything below the shinogi and then etch it with vinegar and dish soap. I clean up the oxides with Flitz, Pikal, Noxon, or Simichrome...lately I have been mixing a little Pikal with mineral oil and then just rubbing the blade til the oxides come off and the steel is clean. My etching solution is now kind of proprietary and includes vinegar, fruit juice, and soap.

 

Christopher: I agree that too many folks polish too highly. There is no texture left and the surface is too burnished to take a decent etch over 1000 - 1500, IMO. I do the shinogiji (everything above the ridgeline on blades that have one) up to 2000 grit and then hand buff with metal polish to get that mirror look. Lately I have been burnishing that surface and I'm not sure but I think I like the burnishing effect a little better.

 

For me, paper (any grit paper) wipes the etching off in a single pass and I'm back to square one. So, I never touch an etched surface with abrasive paper. Christian Griesi used to follow an etch with worn out 2000 grit and water and it looked *stunning* back when he did paper polishes years ago. We all use what works. If you (if I) etched with ferric chloride I could get away with cleaning up with paper because it etches soooo deep the steel in the hamon is literally scarred. And I lose a lot of the subtle activities to ferric...so I don't use it. The weaker the acid, the more passes and etches to tease the little stuff to the surface the better the hamon comes out, IMO. Ferric just smokes out the big stuff and leaves some of the really intricate stuff in the hardening line (especially "stuff" hiding in the habuchi) completely obscured by the deep level of the etch.

 

But that's probably just me. I have to do everything the hard way. :blink::P

 

Brian

Share this post


Link to post
Share on other sites

Some old pix of that same blade by Howard Clark:

 

FLIPSI1.JPG

 

And the last blast from the past...only because this was one of the coolest blades I have ever seen!

 

KUBIKIRI.JPG

 

There was sooo much stuff going on in this blade that I had no idea of before I etched it. And the wrong polish and etch routine missed a lot of what was there. The blade was eventually sold by Howard and was repolished via stones. Patrick Hastings owned it and I saw a pix of it stone polished at one time. It'd be interesting to see that blade up close with a stone polish to note the differences.

 

But now I'm wishin' and you know what comes of that. :lol:

 

Long as I'm wishin'...it'd be nice to have a glass of Oban *and* that blade in my hands at the same time.....now *ThAt'S* a wish! B)

 

Brian

Share this post


Link to post
Share on other sites

This is all good, but what I'm trying to say is that the hamon could look dark or bright depending on how the light hits it, the angle,... how the light is reflected at various angles.

Share this post


Link to post
Share on other sites

 

 

This is the look on many of the traditional, older blades. Is it possible to get this look without the stone polishing? It's kind of a simple bold look. If so, what about with 5160? Todd

Share this post


Link to post
Share on other sites

Yes, I think that's true Tai. Actually, all of the pictures I have posted were taken under very specific circumstances and conditions. And, as the blades are moved in and out of the light or as they are exposed to different spectrums of light from flourescent, incandescent, or natural sources the quality, contrast, and color of the hardened area can look completely different.

 

Actually, it doesn't show in the pictures, but the hamon on this blade was a combination of frosty white and darker grey areas. They whole hamon and its components is made up of millions of little facets and different faces of the crstaline structure...turned just a half a degree out of the light the hamon and the base steel of the blade can easily change places.

 

I have photos of dark hamon on light backgrounds but most of those are photos taken with the oxides still on the blade. But I have seen the effect you are talking about.

 

I'm just not a good enough photographer to capture it. Yet. ;)

 

But, yeah, this is like the original DLP (digital light processors) in that millions of little mirrors can relect light from a specific angle and I have seen colors and rainbows in heavily etched stuff kind of like the rainbow hamons on your stuff.

 

And dark hamons as well. Some of them damn near sinister. :unsure:

 

Brian

Share this post


Link to post
Share on other sites

I have a question fellas, a little off topic.

 

has anyone slightly tempered a blade with a hamon, and kept the contrast?

Christopher Makin told me he tempers his tantos to 400, but loses a wee bit of the sori. Any body else try this? Jerry

 

BTW Brian, nice polish and photography. B)

Edited by Bennett

Share this post


Link to post
Share on other sites

Hey Todd, that picture is a traditionally polished and smithed blade and it has been photographed in the "tradition" to produce a specific type of picture. Check this website for how the photography is done:

 

http://www.nkb.ca/articles/photography/

 

My own pathetic attemps at producing the same effect by placing a blade on a sheet of glass and lighting it in that "very special way"...

 

fatboy-in-space1.jpg

 

My attempt has no hamon (yet...but it is 5160! B) ) but it was shot to exploit all the surface defects and such. The point is to produce a specific type of photograph that shows the blade and not anything else. I'll post pix in the future that are a little closer to the photo you posted. I'm slow...it takes me a bit. ;)

 

The blade you have pictured is a blade in kesho polish and it has hada (grain) and has been differentially hardened. There is no way a 5160 blade of monosteel will look this good but the hamon and habuchi can be photographed in striking detail using these methods. The key is in the way the pix was taken...that and the fact that there is *a lot* of stuff worth photographing going on in this blade.

 

Jerry: Tempered blades give up a little in sori and very little contrast in the hamon if tempered at 350f - 400f depending on the steel. I have tempered 1050 blades and lost not one bit of hamon detail or contrast. But I have limited experience. Our host knows lots about this stuff and so does Randal..maybe they will chime in.

 

Brian

Share this post


Link to post
Share on other sites

Hello folks: I have been etching in lemon/vinegar mix. Only have etched 52100. The hard part is always lighter than the soft spine. Is this not normal?? The softer metal should etch darker than the harder parts, Right???

I am not trying for a hamon just trying to see how I did on my hardening.

The edge is hard and the spine is softer.Grin. I do my etching at 800 grit.Then finish the knife and no temper line is visible.

How can the harder steel take more etch??

 

Chuck

Share this post


Link to post
Share on other sites

I don't find tempering detrimental to seeing the hamon in the polish at all. Especially on modern monosteels I think it helps it... not much to compare it too, I've never really made anything that wasn't drawn at least a little, including tamahagane, which showed hamon fine after a draw as well.

 

dats all I know...

Share this post


Link to post
Share on other sites

In my experience all of the low alloy steel make a less drastic hamon than say, 1050 or something. I have no experience with 52100 but I would assume that the chromium level (52100 is like 5160 on crack to me) would make the blade want to get full hard all over *very* easily.

 

I have seen 5160 blades that were through and edge hardened show a gentle and general lightening towards the edge when etched showing that the steel is harder there than on the back...usually with vinegar and fruit juice etches it takes 10 or 15 etches to get enough contrast to see this.

 

Ferric will do it in one pass if all you want to do is see the difference beween harder and softer.

 

But I'd imagine that 52100 would be the same as any other low alloy steel that hardens easily and my xperience is that the hard stuff ends up lighter and frostier and the softer stuff ends up darker after the oxides are removed and under flourescent or incandescent light.

 

Sunlight is a different animal sometimes.

 

Brian

Share this post


Link to post
Share on other sites

Is it possible to get a hamon line from A-2? I have the perfect size/shape chunk of A2 to make a nice tanto and would like to give it the "authentic" look with a hamon.

Share this post


Link to post
Share on other sites

I have zero experience with air hardening steels. If I were going for the "traditional" looking hamon experience I would bypass the air hardening stuff and go with a shallow hardening steel.

 

Low alloy stuff can make a vivid hamon or demarkation between hard and soft but the line is simple...you don't/won't get waves and dips and all kinds of *CrAzY* activities but you get a nice line.

 

Phill Hartsfield has done a lot of stuff with A2 that has a "hamon" but I have never been able to determine if the hamon is real or just an etched, artificial hamon. My guess is that one should be able to differentially harden an air hardening steel but I have no idea how one would do it.

 

So, I guess I'm not helpng much, am I? <_<

 

Brian

Share this post


Link to post
Share on other sites

I figured it would be difficult to get a hamon with air hardening steel; maybe the higher chromium content. I may give it a try using several different techniques just to see, but I'm not going to get too hung up on it. I have some 1084 and some 1095 I know I can get a hamon with. I did make a nice Puuko with A2 but already gave it away as a Birthday present before getting any decent pictures. Thanks for the info.

Share this post


Link to post
Share on other sites

It would be difficult if not impossible to get a hamon with air hardening steel. Even with a very thick clay coating on the spine it would be hard to slow down cooling enough to get anything good.

Share this post


Link to post
Share on other sites

Have to disagree with you one about getting a hamon on A2, Mete. I played around a bit with A2 back about ten years ago. Wanted to see if a hamon was possible. I also wanted to find out for myself if the stuff would cut... the reason being that I'd been asked by a knife dealer to sharpen a knife made from A2 by a rather well known maker. I told the fellow that I'd sharpen the knife if I could do some non-destructive cutting tests. He agreed. Cutting fifteen pieces of one inch manilla rope would dull the blade from hair popping sharp to 'dull as a hoe'... and that's being generous. With proper heat treat I managed to get about a hundred cuts with a couple of test blades made from A2... but the steel, when ground thin enough at the edge for a blade to cut worth beans, was chippy as hell. It's not anything I intend to use.

 

A rather plain hamon is possible if you differentially harden the blade... just as with 5160. Cooling the spine slowly was not the way I went. I just never did get the spine hot enough to harden. With a little practice, a wavy hamon can be achieved by running a torch flame down the blade, bringing the thinner section up to hardening temp while keeping the thicker areas below the hardening temp. I didn't spend much time with trying to polish out the blades since I considered the steel unsuitable for hard use knives, but a hamon of sorts can certainly be gotten using A2. Keep in mind that the temps you'll need for hardening are well above those that work for the 10XX series, or the low alloy stuff, IIRC. Takes a little practice, but you can get there... if it's where you want to go.

 

Just my .0000000002 cents.

 

Jimmy

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×
×
  • Create New...