Hamon/Temper Line?

[Bobby Urban]

I understand the theory and the purpose.  I also think it really looks nice which is probably 90% of why it is added on most knifes that are going to see normal use.

My question is...  How are you doing it?  Do you cover part of the blade with a heat restricting agent, heat to critical in the forge and quench like that?  Do you heat the whole blade and only quench the edge?  Is there some magic to this?

Thanks for any help

Bob Urban

[Jeremy]

You could just do an edge quench or cover the spine area with clay, satanite, or a high temp fireplace mortar.
 

Get the blade ready for heat treat and coat the spine, then heat to non-magnetic and quench.  Clean it up and temper as you normal do.

To highlight the hamon you can selectively polish the blade, or etch it (much easier)

I usually etch for 20 seconds in a 1:4 mix of ferric acid:water or a 1:1 ferric:white vinegar (what I etch damascus in).

After etching my blades look like this:
 
The opposite of what we're going for.

I use Flitz polishing paste to rub the blade out. Put a little on the blade and rub with your fingers in a circular motion, being careful not to overwork one area. When the flitz loads up and becomes black, wipe it off and put some new paste on. When that's finished wipe it off and buff with an old t-shirt to get rid of the residue.

At this point, the blade will look like this
 
The hard steel releases it's oxides much faster than the soft steel.

To get even more contrast between the hamon line and the grey back, take some more polishing paste and carefully polish the spine down to the line. Now you'll have a polished light grey spine, a satin or mirror edge, and a dark hamon

 

It'll help to switch pastes for that last step... mixing red rouge with honing oil was recommended to me by someone who worked some with Don Fogg.

[Jeremy]

You can't see in that last pic, but there's a white edge on the hamon immediately above the dark line.  Look at robtattoo's recent thread for a better pic.

If you're really careful (and lucky) you can get a wild hamon that looks like lightening running down the blade.

[robtattoo]

Here's what Jeremy's talking about.

Not a brilliant hamon, as it was my first to reveal, but you can see the white temper line.

 
 

[kbaknife]

Let's also toss in that the thread title "hamon/temper" line can be misleading.
They are two entirely different things that normally involve two different steel types.
The true hamon can be found on shallow hardening steels, but not on deep hardening steels.
However, a temper line MAY be found on both.
A hamon can be described as the "storm" that occurs at the meeting of two fronts - one cold and one hot.
You can get a hamon with no clay at all. Simply place your shallow hardening steel in the forge only long enough to austenize the thin cutting edge, and maybe a little more above that, leaving the spine and ricasso fully magnetic and quench the entire blade! Hamon!
A temper line may be created simply by only quenching the edge. But you can do this with both shallow and deep hardening steels.
Or use a torch and only heat up the bottom portion of a deep hardening steel and you'll get a temper line - not a hamon.
It's just too much fun.

[Bobby Urban]

Thanks for all the imfo - My bad on the original question although I think you all realize I was using the words as one.

Jeremy - Do you put the whole blade in the forge with the goop on it?  Does the goop do anything to the forge?

Thanks again - Bob Urban

[Jeremy]

Bob, yup, the whole blade goes in the forge.  The goop doesn't do a thing to it.  Depending on the goop you use you either let it dry completely before heat treating or can go directly after putting it on.  Let satanite and clay dry completely.  Satanite is acually used in making forges, you coat the Kaowool with it to seal the fibers.

The high contrast between the edge and dark spine is really the first step in polishing.  I normally stop there b/c I like the look and it's a whole lot easier than finger polishing the whole blade!