Surprise Hamon!

[boy&hisdogs]

This is my third knife, and first knife out of 1075 (from Admiral). I didn't do anything special to it, I don't think. I heated it to non-megnetic, made sure the color was nice and uniform, then dunked it point down in slightly warm-ish canola oil. I held it still and for what felt like a long time. Tempered at 400 and sanded to 800 grit, then hot vinegar etched.

One thing that may have affected it is that while thinning the stock (mostly done with a handheld grinder and 4x36, went from .130 to .65) it developed a bit of a bow in the middle of the blade, I heated it with a mapp torch to the very dullest red and tapped it straight. Then stuck it in the sand bucket until it was room temperature.

So what do you guys think? Is this a lucky fluke? Did I stumble across something? I've never attempted a hamon before, nor seriously researched them. I've seen clay hardening done many times on YouTube, and I've skimmed a few articles/write ups, but that's pretty much it. I know just enough to know just how little I actually know, if you know what I mean.

 

[Karl B. Andersen]

Where your hamon begins just wasn't up into austenite when you quenched it. One of many ways to get a hamon.
Do it again.

 

[Salem Straub]

Another point is that slightly warmish is not as pre-heated as canola likes to be, especially for hamon... so your quench was slow. You might have got it fully hardened with oil up 130f.
1075 is pretty darn close to eutectoid steel, but still non-magnetic is more of a reference point to know you are ALMOST at heat- the closer to 1080 in carbon content, the closer to non-magnetic you can quench, but much lower or higher in carbon and you'll have to heat 25-75 degrees hotter, depending on the alloy.

Hamon with crazy activity, generally of the "hitatsura" type (a lot of mottled/chaotic activity) can be gotten with a no-clay quench, relying more on the precise heat control and geometry of the blade to achieve differential hardening. Nick Wheeler comes to mind here...