Hamon Help - what caused this?

B

BFrancios

Joined
Jul 9, 2012
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65
Need help from some experienced Hamon folks.

I have hardened this blade 3 times attempting this hamon. On the first two attempts the clay/satanite fell off during the quench and made things "fuzzy". Finally got it to stick through most of the quench on this attempt, thanks to Don Hanson for his reply on a thread reply about not letting the satanite dry before heat treat.
However take a look at the pic below. I have a soft area at the spine. FC does not darken this are much at all. This is the shiny are about 1/3 back from the tip at the top of the blade.


DSCF0044.JPG



The other side of the blade is fine. The corresponding area on this side is hard. A 60 HC hardness file just barely bites the steel, seems about as hard as the blade edge using this imprecise method. FYI - the blade has had its first temper.

DSCF0046.JPG


These are some of the best Hamons I've created. The blade pics above are roughly sanded to 150 grit and then etched. I have never had a hamon show that well at such a low grit. That said, I have never been this frustrated when trying to get a clean hamon on a blade either.

My process:
-Forge PID set to 1450F. Trying to stay close to the austinization point.
-Homemade firebrick forge, powered by 2 torches front and back. It has hot spots. The set temp is the cool spot in the middle of the forge.
- On a blade this large I move it around, trying to get an even color, the one near the TC, and similar magnetism across the entire blade.
- Quench in Parks 50 when I think I have and even temp.
- Temper at 380

I suspect the above "shiny spot" was due to a cool spot on the blade but the fact that one side hardened contradicts this. The side with the shiny spot was the one laying up against the forge wall just before the quench.


Any ideas?


Barry
 
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It doesn't appear that you've done any grinding on the blade after heat treating at all. I can still see residual clay on the ricasso. You need to grind to clean steel and remove any decarb if you want to have any idea what you truly have in the hamon when etched.

Also, did you normalize between hardenings?

--nathan
 
I'll tell you something else Don Hanson will say:
"Ya' gotta play with it".
There are no cut and dried, "one size fits all" answers to hamons.
The variables are endless.
Finish grind and hand sand this blade.
Etch it to see what you've got.
Remember exactly what you did to get this result.
Adjust accordingly to get what you want on the next one.
Repeat.
Repeat.
Repeat.
For years.
 
The blade was sanded clean with 150 grit across the bulk of the blade. Some of the area around the riccasio and flats was not cleaned up to a shiny state or much sanded at all. Since this is my 3rd attempt, I am cutting some corners until I think the Hamon is a keeper. I am worried about edge thickness in case I need yet another attempt. By rights, this blade should have cracked during the last quench. It is right at .02 at the edge.

The blade was normalized and annealed between heat treats, 4 cycles 1550, 1450, 1350, and 1300. Then an anneal.

Also, I am going with a "Frontier" look on the knife. The ricassio, flats and spine will keep the decarb look.

Once I am sure the Hamon is good I will clean up the plunge and grind lines.
 
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Just to put some closure to this, below are some pics of the final result. I did decide to go with this heat treat and grind it to final thickness. The grinding helped but I still have a fuzzy secondary hamon where the bright spot is in the original photos. AND it now extends to the other side of the blade.
I am telling myself it adds character to the blade and moving forward.

Thanks everyone for your suggestions. They helped. I am going with the theory that this section was slightly below the austenizing temp, and a hamon formed in this area. I will watch both sides of the blade more closely next time. I am pretty sure I was using the "good" side of the blade when judging color/temp and magnatism just before the quench. Need to check both sides more closely in the future.

Don, YEAH! Need a bigger forge AND a heat treat oven for more even heating. The next shop project will be a proper forge build so I can more easily do knives over 4 inches. The heat treat oven may have to wait awhile for my hobby budget to get a little fatter.

The sun was setting when these pics were taken, sorry for the bad lighting.

DSCF0075.JPG


DSCF0070.JPG



Thanks again everyone for your help.


Barry
 
Something I would like to add is that when you sand usually sand to 150 and etch its just a rough idea of what the hamon will look like. When you get to a much finer grit and polish and maybe a little etch its gonna bring out so much more usually and you will see its true colors so to speak.

Also getting past the decarb layer or whatever it is. The decarb around the clay will show kind of a false hamon sort to speak that will etch and everything.

Atleast this has been my experience.
 
Thanks Quint, looks like we posted at about the same time.
I think I was letting my reluctance to grind further get the better of me. Like you said, I should have ground the blade a little more to get the full picture of what the hamon looked like.

Barry
 
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