Hamon Formation

David Stifle

David Stifle

Joined
Nov 20, 2008
Messages
10,188
Hi All,

It's been my experience a hamon rarely follows the clay line. In fact, while I've got some really great hamon's over the years, seeing them for the first time is always a surprise. So, my question is-how can a maker obtain greater control over how a hamon lineturns out?

One thing I'd like to change, but am not sure how, is to get rid of the furnance cement, because it's difficult to apply precisely. What substance do you guys use?

Thanks,

Dave
 
I use straight Satanite


Accurate Hamon is all about temperature control and heat cycles prior to HT

you need a very consistent normalization regime and you need to be very familiar with the exact Aus temperature of your chosen steel.
 
So Stephan,

In order to get those results one needs a temperature controlled oven? I use a coal forge and judge the temps by color.Doesn't sound like I'm properly equiped to do as you say.

Dave
 
David Stifle said:
So Stephan,

In order to get those results one needs a temperature controlled oven? I use a coal forge and judge the temps by color.Doesn't sound like I'm properly equiped to do as you say.

Dave
Click to expand...

I wouldn't say "need" that's somewhat subjective.

however, in order to achieve the control required, you can save yourself many years of trial and error by using a controlled environment.

I just bought a pyrometer setup from Auber Instruments that cost me less than $60
a little inswool in a 20 Gal drum and 10 dollars worth of plumbing parts later I have a decently controllable furnace.

total cost about $150.

but I'm still going to get an evenheat from Tracy as soon as I can, just to nail down my temperatures a little bit better
 
I tried the elec HT oven a few years ago and went back to the forge for hamon. The temp control forge Stephan speaks of is the ticket, I just haven't got around to building one yet.

There is no such thing as complete control over hamon. Actually that would take most of the fun out of it.:)
 
I have a loooooooong paragon oven and like Don prefer to use my forge. One reason is that All but one of the ten blades that I austinitized in the oven cracked in the quench. I used temps from 1425 to 1500. I have since done maybee thirty blades in the forge and quenched in water with no problems. The biggest influnce on where the hamon lies and how closely it follows the clay for me seems to be temp and clay thickness. Parks seems to require more heat and less clay than water. steel used has been 1050 through 1095 5160 and w2. No wasn't able to get a "decent" hamon on the 5160.
 
The final hamon you get is somewhat of a mystery, but the methods are not.

I have posted several hamon tutorials in the past, but here is a simple guide for a suguha hamon:

Start with a blade that has been through foundation shaping (sugata), and is ready for yaki-ire. Normalize the blade before HT. The condition of the steel before HT will greatly affect the final results.
While not everyone agrees, it seems that machine work can create stresses that show up in the final hamon results. Many smiths make the blade by whatever method they wish ( forging is the usual way), and then anneal or normalize the blade. After that they do all the shaping work with stones and files.

Make a simple stand/clamp that will hold the blade by the tang and allow you to work with both hands. The ability to rotate the blade and work both sides is important. A trip to Harbor Freight will yield some inexpensive clamps that rotate. Mount the clamp firmly so you can sit or stand by the blade and do the clay work.
If you are married, or have a good partner, Don't do clay coating in the kitchen.

Use satanite for the clay. you will read about AP-green, Atlas/Rutland furnace cement, etc., but satanite is cheap, reliable, and works perfect.

Make a thin mix, about like heavy cream, and apply a wash to the whole blade. Dry with a hair dryer or heat gun.

Thicken the mix with more satanite until it is about like sour cream. Apply this to the spine area, bringing it down toward the edge. Stop about 1/4" before the edge. Do the same to the other side. Use a popsicle stick to smooth the layers to about 1/8" thick. Take your fingers and wipe the edge in a straight line ,removing the excess along the edge. This will leave the ha exposed for about 1/4". Dry the blade with the hair dryer.
Note: If you as doing a blade that you wish to control sori somewhat, you can wipe the satanite off the mune ( spine).

Do yaki-ire as desired, keeping the austenitizing temperature on the lower side.
After quench, clean the blade and examine the edges for ha-giri - tiny cracks running from the edge inward. If there, discard the blade and start again.

A light sanding, followed by a quick dip in FC may show the potential hamon line. This is not the final result, just a confirmation of different structures in the blade.

If inspection goes well, do the shitaji-togi ( foundation polishing) - the hamon may not be visible at all at this point. Get all the shaping right at this stage. Removal of excess metal will not be possible in the next stage.

Please Note:
The blade will be getting sharp as you do togi. Use caution as you go, and extreme caution in the final stages of shiage-togi. Misuse of things like hazuya stones and nugui can lead to having no finger prints if not done right. Doing a hybrid polish on your first several blades is a good idea.

Continue onto shiage-togi ( finish polishing), where the hamon will start to appear.

Use of a variety of methods and etchants can bring the subtleties of the hamon out in the final steps.

General notes:
The hamon will not be exactly where the clay stops. Experience, and your own equipment will teach you how to place the hamon.

If the hamon does not appear to have developed, re-do the clay work and HT.

Note that fast oil is safer, but any hamon will be faint or may not exist at all. Brine will develop the most activity ( hataraki).

More complex hamon, greater hataraki, ashi, and other features can be developed by changing the shape of the edge of the thicker clay line. Make the line wavy and you can get notare; poke it with a stick into small ridges and get Choji or many other patterns; make small lines to the edge with a slightly thinned slurry and create ashi.


There are several good books on the subject, and some good DVD's.
A few are:
Walter Sorrells - Hamon ( and his entire set on Japanese blades)
Setsuo Takaiwa - The Art of Japanese Sword Polishing
Clive Sinclaire - Samurai Swords

Stacy
 
dont mean to highjack this thread but why does W2 seem to turn out amazing Hamons its incredible 10XX and others will lend a nice hamon but W2 seems to have the best contrast, and the most hamons.
 
A hamon forms in shallow hardening steels. Any alloy ingredient will make the steel deeper hardening, and thus wash out or block the formation of the hamon. 5160, O-1, D-2, and other higher allow steels are not suitable for hamon development.

A short course in hamon formation may be in order:
A simple steel has carbon and iron. Anything else is an alloy ingredient. W2 has about 1% carbon and 98.25% iron. There is also a .25% amount of manganese, silicon, and vanadium ( typical assay). These alloy amounts are small enough to have little effect on the hardenability.

When the steel is heated to about 1450F, the carbon goes into solution, and forms a structure called austenite. Upon cooling the steel can do one of several things. If cooled slower than one second to get below 900F, it will form pearlite, a soft structure of steel. If cooled fast enough to miss this "pearlite Nose", the steel will remain as supercooled austenite until it reaches about 400F, where it will start converting into martensite. Martensite is the hard steel we want for cutting tools. Besides the hardness, martensite and pearlite have different crystaline and visual properties. They also react differently to etching.

Now, when the clay coated blade is heated to the austenitization point, and then quenched in water, the edge immediately cools to below the pearlite nose, and at 400F converts into martensite. The clay insulated spine retains its heat, and cools slower, thus converting into pearlite. The junction of the two structures is the hamon. This area is a mixture of fine pearlite, coarse pearlite, and martensite crystals. Highlighting the effects by proper polishing to bring out the optical characteristics of these structures is the skill required in shiage-togi.

Stacy
 
This is great info, guys, and I have a better idea of what to do the next time I go for a hamon. Stacy, your last explanation was the clearest description of what a hamon is and why it forms I've yet read.

Dave
 
Nebulae said:
dont mean to highjack this thread but why does W2 seem to turn out amazing Hamons its incredible 10XX and others will lend a nice hamon but W2 seems to have the best contrast, and the most hamons.
Click to expand...

not all W2 (or any grade steel for that matter) is created equal.

Don's W2 has a very fortunate amount of alloy. If it had .1% more or less of any alloy ingredient it would react very differently in terms of Hamon, but it would STILL be W2.

Aldo's 1084 is the same way in my use, it has JUST enough Manganese to do the job, but not enough to throw off the shallow hardening aspect which allows for Hamon. MOST 1084 is about useless for Hamon (or at the least, very frustrating)
 
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