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ethanknott

hamon process, possible mistake?

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So I'm not sure if I've made a mistake here or not. Trying to put a hamon on a tanto that was a 1095 file. Normalized a few times after forging, then cold forged, normalized 2x, ground and filed etc, then I clayed the blade. Have I normalized enough for HT? Can I do the normalize 3x with the clay on? Or did i waste a bit of time and clay, and need to take it off to normalize, then reapply for HT?

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Why on earth would you cold forge, that's the real question.  :huh:  In the event you didn't fracture the heck out of it by so doing, the two normalizations might have been enough.  A lot depends on how much stress you put back into the steel by beating on it cold.  

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Just tapping back and forth, getting everything nice and in line... I tend to not notice half the tiny wobbles n twists until I've done a bit of grinding, and am too lazy to light the fire again. I use a mostly polished 16oz ball peen for that bit, so it's pretty dang gentle.

Would the clay screw up the normalizing? Like if brought up to critical, can you normalize? Or is it pretty much once the clay is on and heated up its quench or start over?

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3 minutes ago, ethanknott said:

Just tapping back and forth, getting everything nice and in line... I tend to not notice half the tiny wobbles n twists until I've done a bit of grinding, and am too lazy to light the fire again. I use a mostly polished 16oz ball peen for that bit, so it's pretty dang gentle.

Would the clay screw up the normalizing? Like if brought up to critical, can you normalize? Or is it pretty much once the clay is on and heated up its quench or start over?

I straighten cold a lot of times myself. You had me worried with the "cold forged" too. 

I would do it 3x normally, but 2 may be enough. I'm not sure.Whatever you do, do NOT normalize with clay on. 

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Beat me if I'm wrong but straightening cold will induce stress in the steel so you will have to normalize at least once again or risk warping.

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53 minutes ago, Joël Mercier said:

Beat me if I'm wrong but straightening cold will induce stress in the steel so you will have to normalize at least once again or risk warping.

He did say he normalized twice more after straightening.  I usually straighten with twisting wrenches rather than impact if I'm doing it cold.  A little less stressful for all involved.

And Ethan, you did have me worried, I was picturing you trying to beat the snot out of it cold. :lol:  You should be okay.  Try it and see, you can always redo the HT if aren't happy with the results.

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I'm not a homon expert, but I have normalized with the clay on a few times.  The only problem I have had is that sometimes the caly doesn't survive the 3 extra heating and cooling cycles.

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Ok so i have only attempted a hamon a couple times and they were on the wrong kind of steel (52100) but from what i can gather about a hamon is it is basically a differential heat treat but with character. So you want to bring the edge up to temp as fast as you can without heating the rest of the blade. Thats what the clay is doing is insulating it as you heat the edge almost like a torch quench but with the forge. So you want to put the clay on while the blade is cold that way you are not starting with an already heated or warmed up blade from your normalizing cycles.

Edited by Jeremy Blohm

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Actually, what the clay does is break up the vapor phase of the quench enough to prevent full hardening of the underlying steel.  You do want the underlying steel to be up to temperature or you won't get the microstructures that cause the visible effects of hamon.  So basically the opposite of what you said.  ;) This is also why you need a shallow hardening steel to get hamon, a deep hardening steel like 52100 will through-harden even under the clay.  

Yes, you do apply clay to cold steel, but that's just because it's easier to do.  You then heat slowly to bring the whole thing up to temperature.  A fast heat brings the edge up too fast, and with the kind of steels that produce good hamon will cause unwanted grain growth on the edge while the spine is still coming up to heat.  Not to mention too fast a heat tends to blow the clay off. Finally, if the spine is not up to heat you will not get the sori effect on a longer blade.

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Nice to know. I was thinking of it wrong. Thank you once again alan for clearing things up for me.

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2 hours ago, Brian Dougherty said:

I'm not a homon expert, but I have normalized with the clay on a few times.  The only problem I have had is that sometimes the caly doesn't survive the 3 extra heating and cooling cycles.

The reasons I don't do it are... The clay will hold heat; when I normalize I want my blade to get up to temp, and cool down at close to the same rate. On longer blades, the edge cooling at a faster rate can actually cause it to warp downwards. Also, the clay could break off. 

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46 minutes ago, Zeb Camper said:

The reasons I don't do it are... The clay will hold heat; when I normalize I want my blade to get up to temp, and cool down at close to the same rate. On longer blades, the edge cooling at a faster rate can actually cause it to warp downwards. Also, the clay could break off. 

That's a good point.  I rationalized that away when I did it because I didn't care so much about the crystal structure at the spine of the blade, but the warping could be a real issue.

Since I finally bought some anti-scale compound, I don't do it that way anymore.  The only attraction it had for me at the time was to not have to polish the scale off the blade an extra time :)

Edited by Brian Dougherty

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2 things yalls info has made me think of (thanks guys btw :D) the steel is shallow hardening, so does that mean I need to be careful with how much bevel I grind off after ht? I'm doing a regular flat bevel, I'll have to get specific measurements when I get home, but the blade is ground to maybe a bit less than dime thick. Wouldn't want to grind out the hamon lol. 

Also, how much curve can I expect the ht to put into the blade? It's not particularly long, only maybe 9-10" blade (gotta measure these things haha) and I put a little bit of curve during forging for asthetics. I don't expect much, if any, extra curve, but this is my first attempt so I have no real clue what I'm doing.

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A lot of the bend/curve is dependent on the whole geometry of the blade, its size etc. On a knife sized flat ground blade I think the bend would likely not happen at all. I've never seen it happen or heard of it on a 10" blade, although I am sure that it is possible I don't think it probable.

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"Shallow" in this instance is going to be about 1/16" in from the surface, from both sides of course, so you won't grind it off.  A strongly V-shaped cross section will move more, but in oil it will move down rather than up.  

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Cool, I'll let yoy guys know how it goes, just gotta wait for a not too rainy day now.

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Got the blade quenched... Before and after pic. The after pic is the unsanded side, i polished the other side to 800 and a light buffing to clean stuff up, then dropped it in some ferric chloride to see how the hamon turned out.

Goes all along the blade, looks nice and even, blade is hard and spine is soft, etc. No good pic though because i didn't have a lot of etch time, and I'm not entirely sure how to get the hamon to pop like you pros. How does one etch a hamon correctly? 

Tried white vinegar (fairly warm) and nothing really happened. Tried ferric chloride for 10-30 secs at a time with a light rubbing of 2000 grit sandpaper, repeated about 10 times. Hamon started to appear but only faintly. Should I just do the ferric chloride again and leave it in a bit longer and lather-rinse-repeat it several more times?

IMG_20180208_102008.jpg

IMG_20180208_132826.jpg

Also, is the tempering process the same as normal? Just chuck it in el heat box for an hour? 

Edited by ethanknott

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