Help me dissect this hamon

[Bühlmann]

So this was my first attempt. Blade was hand sanded to 400gr before applying clay. I used 26C3 from AKS, a thin coat of NoScale 2000 over the entire blade, and two coats of Hamon 1800 on the spine:





Here is the post HT result after hand sanding to 1000gr followed by about 6 ferric chloride dips (approximately 15-20 sec each) with a 1200gr wet sand between dips:







I don’t like it at all. I don’t understand the blotchiness or the lack of uniformity. What can I improve and/or change to get a better visual representation?

 

[Tom Lewis]

How did you heat treat your blade?
It looks like maybe you didn't grind off all the decarb.
I use 0000 steel wool instead of sandpaper between etches.
I use 1 part FeCl to three parts distilled water.

 

[Tom Lewis]

Also, how did you polish the blade after etching? I use 1500 silicon carbide grit mixed with a light oil to polish the blade.

 

[Bühlmann]

How did you heat treat your blade?
It looks like maybe you didn't grind off all the decarb.
I use 0000 steel wool instead of sandpaper between etches.
I use 1 part FeCl to three parts distilled water.

1475F for 10min soak, quenched in Parks 50 followed by a 450 temper (x2) for this application.

I don't think there should have been much of any decarb, since I used the NoScale 2000 and hand sanded from 220-1000 before etching. But it may be a possibillity I guess, given the splotchiness?

My FeCl mix is 1:3.78 distilled water.

I have not polished the blade. What the pictures show is 6 etch cycles with a 1200gr finish. This is a practice blade in 26C3 for me to try out the hamon and see how the high temper works out. I don't plan on spending a lot of time to polish what looks like a turd, but I do want to know how I can prevent making another turd when it really matters.

 

[Keith Nix]

High temper on 26C3?

 

[Joshua Fisher]

That’s decarb, you didn’t grind enough off after heat treating to get down to clean steel and your actual hamon. Hand sanding alone is often not enough which is why I don’t take my blades up to a finished grit and geometry before hardening. For hamons I grind my blade 80% up to a 120 finish then clay and harden. Also you don’t necessarily need 2 coats of the 1800 one proper coat should be enough

 

[Joshua Fisher]

After heat treating I drop back to 50-60 grit and grind and test etch until no decarb is present then I start moving up in grits. A 5 second dip in ferric will show you the white splotchy decarb and where you need to grind more.

 

[Robert Erickson]

Agree it looks like decarb.
Also, I have found the best temp for hamon with 26C3 is around 1460 in my kiln.
Here's a recent one in 26C3 that I completed.

 

[Bühlmann]

Awesome! Thank you for the replies, all!

 

[Bühlmann]

High temper on 26C3?

Why not? I wanted to try for a hamon, which 26C3 is supposed to be good for. But I didn’t want a super hard blade so I could have the hamon on a small knife that doesn’t take all day on diamond stones and the blood of three virgins to sharpen.

 

[Stuart Davenport Knives]

First, yes that is most likely decarb. Sure looks like it.

Second, even at 66HRC, 26c3 is very very easy to sharpen. But with that said, a 450°F temper still gives ~61HRC, and offers the best toughness for 26c3.

 

[Stacy E. Apelt - Bladesmith]

You aren't looking at the hamon. What you show is the surface effects of the HT. The hamon is hidden under it. All that is wrong is the blade isn't finished. Take it back to 220 grit and sand the surfaces clean of decarb. Then go up the grits to 800 and etch. You will start to see the real hamon.
Use finer papers and other polishing agents to develop the hamon fully. It looks like there is a nice one under all that crud.