Odd differential hardening results, weird hamon

Lerch

Well-Known Member
Hi all,

i was working on this knife for a buddy and had a odd hamon show up. it doesnt follow the layout of the clay that i put down at all.

here is a pic of a different knife but this is the same outline of clay that i did . the heavy clay layer is on the right obvioulsy, the strange looking line in between the heavy clay layer and the blade edge is where i wiped way the excess clay to form the line i desired.
326244_252901914764439_100001338979988_692159_957592772_o.jpg


okay so this is the end results after i sanded down the knife and etched it in ferric chloride a few times and cleaned up with Never Dull.
325616_252902151431082_100001338979988_692160_795568884_o.jpg


the hamon only extends part of the way down spine where i placed the clay and the small dot towards the tip of the blade, well i have no idea how that got there. I did a extremely thin layer of satanite clay at first and this was pretty much completely even all over. i dried this in a toaster oven at a little over 100degs and then applied the 1/16" thick layer of clay like you see in the first photo.

well any ideas why the temper lines would have shown up this way? i went ahead and polished up and finished the blade since i think the buddy of mine will appreciate the oddity of the blade, he generally like this kind of thing and the edge seems to be hardened effectively.

any ideas?

thanks
steve
 
Last edited:
After 75 views no one has a idea on how the temper lines could have ended up with way? i have had something similiar happen again with another differentially heat treated blade, the temper lines were way past where the clay line was, i am thinking that my base layer may be a little to thick.

though this still would not explain the temper lines in the blade in the pics above.

still hoping someone has a idea

thanks
steve
 
The reason it's like that is because your HT temp was too high, what type of steel is it? If you can tell me that I might be able to help more. I don't put clay any where but where I want to insulate the spine, also the rule of thumbs for putting clay on the blade is a 1/3 of the blade width. Steel has a mind of it's own, I don't think I've ever had the hamon follow the clay, which for most of mine, is a good thing. It makes for a more dramatic hamon.

The way I put the clay on my blades is by coating the top 1/3 of the blade, making sure I cover the spine pretty thick, after that I do either angled lines toward the tip or straight lines toward the edge, keep those lines at least a 1/4 to a 1/2 inch away from the edge, the clay for the lines need to be thinner, the rest of it I put on about an 1/8" thick except the spine, I don't pile it on, but it is thicker. Then I let it dry completely, either by letting it sit over night or by setting by my forge while it's running, sometimes if I'm working during the day time and it's warm enough I'll put it in the sunshine, it'll usually dry in an hour or so on a hot day. I've been thinking about doing a WIP on how to do a hamon, it seems everyone has difficulty getting it down at first, but once you get it, you'll find yourself trying to get it on every knife you make. It adds so much distinction, so much character to the blade, I think because no two hamons are exactley the same, which makes the knife a more unique. Hope this helps, Rex
 
The steel is Aldo's 1095, 1/8th thick and i heat treated at 1450deg for 5min . i coated the entire blade becuase Fowlers tutorial recommended it, somehting about it breaking up the turbulance in the initial quench cycle.
 
Did you quench in oil or water? From what I've read on other posts, if you are quenching in water, you can do a thin coat all over with a thin slurry of clay that then put a thicker, heavier coat on the spine over it. If you are quenching in oil, I believe that most advise that the thin slurry coating be omited.

Doug
 
I am quenching in Parks 50 oil heated to about 130deg. I was not aware of that, well i am going to be doing 2 more knives on wednesday so i may have to try them with only the heavy layer and no base layer

thanks
steve
 
One of the fun(?) things about knife making is experimenting to see what works and what doesn't or what comes up when you don't expect it. I remember a post where a smith quenched a short sword/long knife blade point down in a tank of quenchant. He didn't coat the blade with anything. I don't remember whether he was using oil or water but the blade went in straight and came out with a beautiful curve in it. Quick design change.

Doug
 
haha,

well i will try this next one with out the base layer and we will see what happens. I have one i am finishing up tonight and i should get pics of it on the forum late this evening. it had a much thinner base coat of clay and the hamon turned out much more like the intended design.

thanks
steve
 
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