Why use reactive cladding on good knives?

For questions/topics that don't fit into the other, more specific forums.
Robstreperous
Posts: 2497
Joined: Fri Jan 27, 2017 11:46 am
Location: Long Island
Has thanked: 120 times
Been thanked: 453 times

Why use reactive cladding on good knives?

Post by Robstreperous »

So I admit, I struggle trying to maintain the cladding on my reactive knives. I'm working on it, just received some tips from a fellow forumite -- and I'll get better. Still this has me wondering....

Why would a maker choose to use a reactive cladding on a knife when it's so much easier for the user to maintain a non reactive or less reactive material? I get why we do it with cutting edges. But what purpose is served by choosing a reactive steel for the cladding?

To this point I'd always thought of the cladding's purpose as mostly ornamental and to protect the core steel. Having worked lately with a couple of more reactive blades I'm beginning to realize there's probably something more to it.

So... How come?
jacko9
Posts: 2386
Joined: Sun Jan 29, 2017 12:51 pm
Location: SF Bay Area, Ca
Has thanked: 410 times
Been thanked: 190 times

Re: Why use reactive cladding on good knives?

Post by jacko9 »

It is my understanding that the soft cladding on the exterior adds support to the hard core steel. One reason to use reactive steel as cladding could be the ease of bonding to the core during the forge welding step. Stainless Steels while being less reactive also inhibit non-melting forge welding. I know that this is a simple explanation to a complex joining process but, it's only my simple opinion.
gladius
Posts: 5295
Joined: Sun Jan 29, 2017 7:59 pm
Has thanked: 780 times
Been thanked: 911 times

Re: Why use reactive cladding on good knives?

Post by gladius »

Knives with soft iron cladding 1) dampen the vibration better than stainless thus minimizing potential damage - they feel better on the board and 2) are actually easier to thin as they wear. I also think they are easier to forge. Once a solid patina is formed, reactivity diminishes considerably. Before stainless, this is all there was and people got along just fine knowing how to care for them. I still have many of my grandfathers carbon knives he passed on and they are perfectly serviceable.
timos
Posts: 1437
Joined: Wed Jan 25, 2017 3:01 pm
Location: oxford, MA
Has thanked: 100 times
Been thanked: 133 times
Contact:

Re: Why use reactive cladding on good knives?

Post by timos »

Carbon steel is one thing...but iron cladding is a total #$%^. It doesnt want to patina very nicely, it seems to turn orange patina, looks alot like rust. I get a decent looking patina with mustard but it wipes off too easily. I am wondering what do the manufacturers suggest to maintain the very soft iron claddings? Is there somewhere Shosui has given instruction on proper maintenance or forcing patina on his AS knives cladding? The soft cladding of any type certainly makes things easier in the manufacturing process.
Tim Johnson
Oxford, MA

“In the beginner’s mind there are many possibilities, but in the expert’s there are few”
--s. suzuki
Image
Web: http://www.timothyjohnsonknives.com
Email: tim@blackstoneknife.com
Instagram: @timostheos
User avatar
Kit Craft
Posts: 4844
Joined: Thu Jan 26, 2017 8:57 pm
Location: Pennsylvania
Been thanked: 11 times

Re: Why use reactive cladding on good knives?

Post by Kit Craft »

timos wrote: Wed Oct 18, 2017 3:43 pm Carbon steel is one thing...but iron cladding is a total #$%^. It doesnt want to patina very nicely, it seems to turn orange patina, looks alot like rust. I get a decent looking patina with mustard but it wipes off too easily. I am wondering what do the manufacturers suggest to maintain the very soft iron claddings? Is there somewhere Shosui has given instruction on proper maintenance or forcing patina on his AS knives cladding? The soft cladding of any type certainly makes things easier in the manufacturing process.
True or not I recall reading that patina is not acceptable in most pro environments in Japan. What they do is simply not let it patina. Clean and polish it after every shift. Again, just hearsay.

That said, non knife nut people probably don't care about what a patina looks like as long as it functions.

Thing about iron cladding that is interesting is that some of it is terrible to maintain and some of it is not.
Robstreperous
Posts: 2497
Joined: Fri Jan 27, 2017 11:46 am
Location: Long Island
Has thanked: 120 times
Been thanked: 453 times

Re: Why use reactive cladding on good knives?

Post by Robstreperous »

timos wrote: Wed Oct 18, 2017 3:43 pm Carbon steel is one thing...but iron cladding is a total #$%^. It doesnt want to patina very nicely, it seems to turn orange patina, looks alot like rust.


As usual Tim... you nailed it right on the head. I've had my worst problems with iron claddings. As these were high(er) end knives by very well regarded smiths I'm assuming it's a hole in my own knowledge. I'd really like to know what the positive tradeoff is for using these claddings. I'm certain there must be one.

I'm also going to add though a pro who's giving me some tips on how to better maintain the cladding -- and traded me for one of the knives in question didn't find its cladding all that terrible although --- for the line --- he did trade me for a semi in order to compliment his (non iron clad) AS and White edged knives.
Last edited by Robstreperous on Wed Oct 18, 2017 4:16 pm, edited 2 times in total.
J david
Posts: 1109
Joined: Sun Jan 29, 2017 5:07 pm
Been thanked: 5 times

Re: Why use reactive cladding on good knives?

Post by J david »

The best patina is not forced in my opinion. I've never had a lasting forced patina.

This patina is very stable and cannot be scrubbed off. This is just a couple of months of normal use.
Image
User avatar
Kit Craft
Posts: 4844
Joined: Thu Jan 26, 2017 8:57 pm
Location: Pennsylvania
Been thanked: 11 times

Re: Why use reactive cladding on good knives?

Post by Kit Craft »

J david wrote: Wed Oct 18, 2017 4:12 pm The best patina is not forced in my opinion. I've never had a lasting forced patina.

This patina is very stable and cannot be scrubbed off. This is just a couple of months of normal use.
Image
Looks good. Yep, I like natural patina too. I know it is a pain in the ass for the first week or so but I do what Jon told me to and let a "deep" patina set in before I quite babying the knife. Wet towel / dry towel after every single product. That is after each half onion or after two or three potatoes etc, frequent cleaning. I have no problems after about a week or ten days as a home cook. I imagine it would be a shift for a pro. Even with my Tojiro with is freaky reactive.
Robstreperous
Posts: 2497
Joined: Fri Jan 27, 2017 11:46 am
Location: Long Island
Has thanked: 120 times
Been thanked: 453 times

Re: Why use reactive cladding on good knives?

Post by Robstreperous »

That does look nice. But even after way more than a week with some deep patinas I'm finding the iron clad knives still taking an ugly brown patina. Hence the question... Why use a highly reactive cladding?
Chefspence
Posts: 2504
Joined: Thu Jan 26, 2017 11:03 pm
Has thanked: 2 times
Been thanked: 32 times

Re: Why use reactive cladding on good knives?

Post by Chefspence »

Way too much thought and work :)
User avatar
Kit Craft
Posts: 4844
Joined: Thu Jan 26, 2017 8:57 pm
Location: Pennsylvania
Been thanked: 11 times

Re: Why use reactive cladding on good knives?

Post by Kit Craft »

Chefspence wrote: Wed Oct 18, 2017 6:02 pm Way too much thought and work :)
Blasphemy! Patina management and knife sharpening are two things that are not work! Fun, man, fun!
User avatar
ken123
Posts: 5342
Joined: Wed Jan 25, 2017 2:53 pm
Location: Northern California
Has thanked: 253 times
Been thanked: 316 times
Contact:

Re: Why use reactive cladding on good knives?

Post by ken123 »

If memory of a number of years ago serves me well, Watanabe used boat anchor or chain to make his cladding. I also recollect that his knives are pretty reactive. Correct me if my ideas are wrong or no longer correct.

So my general point is that not all iron claddings are the same - some more reactive than others.

Another point. A while back, I had (still have) a Spyderco mule made of Aogami Super (AS). It is solid AS. I was having a hard time sharpening it. I sharpened a kitchen knife - clad AS and left the mud on the stone and went back to the Spyderco AS. Now the knife sharpened well. I concluded that the metal swarf which included AS and cladding swarf somehow helped the sharpening process - perhaps some burnishing effect - I don't know.

A clad blade is generally easier to sharpen than a solid steel blade. Stainless cladding is relatively new. Iron cladding is relatively easier to work with especially if the knifemaker is forging the cladding as opposed to getting steel already clad.

---
Ken
Kalaeb
Posts: 3271
Joined: Thu Jan 26, 2017 8:59 pm
Location: Wisconsin
Has thanked: 208 times
Been thanked: 390 times

Re: Why use reactive cladding on good knives?

Post by Kalaeb »

There are lots of reasons why a forger may use iron over stainless. Stainless requires higher heat and more time to forge due to it being less thermally conductive. There are also suggestions of greater carbon migration with stainless. Would love for a smith to chime in.
timos
Posts: 1437
Joined: Wed Jan 25, 2017 3:01 pm
Location: oxford, MA
Has thanked: 100 times
Been thanked: 133 times
Contact:

Re: Why use reactive cladding on good knives?

Post by timos »

Carbon migration is negated with the use of thin pieces of nickel, that is the shiny thin line you often see between the core steel and cladding.

Iron cladding is certainly the traditional way, and perhaps the price on some of these knives is really not to do with the materials themselves but more for the time of an experienced and traditional smith.
Tim Johnson
Oxford, MA

“In the beginner’s mind there are many possibilities, but in the expert’s there are few”
--s. suzuki
Image
Web: http://www.timothyjohnsonknives.com
Email: tim@blackstoneknife.com
Instagram: @timostheos
milkbaby
Posts: 594
Joined: Sun Jan 29, 2017 11:12 am
Location: Sunny Florida
Been thanked: 2 times

Re: Why use reactive cladding on good knives?

Post by milkbaby »

I agree it's probably what Tim says above: tradition. Plus easier to forge weld to the core unlike stainless cladding, possibly less likely to delaminate during heat treating too?
Bob Z
Posts: 1341
Joined: Wed Feb 01, 2017 8:49 pm
Has thanked: 156 times
Been thanked: 887 times

Re: Why use reactive cladding on good knives?

Post by Bob Z »

That blue patina is gorgeous! In my only few years buying knives it seems that the AS clad knives get this color while the rest of the knives i have turn gray or dark colored. Would be awesome if my Tojiro would get to be that color!
Lepus
Posts: 4561
Joined: Thu Jan 26, 2017 10:06 pm
Location: Durham, NC
Been thanked: 4 times

Re: Why use reactive cladding on good knives?

Post by Lepus »

I don't think it's as much about any benefit to the buyer as it is an easier and cheaper process for the smith. Thinning carbon is nicer, for sure, but it doesnt make a huge difference to me.

For some really high end makers, Kato and Shigefusa come to mind, softer cladding is a lot easier to work with non-powered tools. For low end lines, I bet it has a lot to do not only with the cost of the steel but also the cost of the abrasive and labor used to produce the grind. I've seen how long it takes to condition those big wheels and I've blown through plenty of sandpaper and disc sander pads on hard, oily wood. I'd be pretty surprised if that didn't factor into knives like the Tojiro ITK and Yamashin. And I do think the welding process and risk of failure come into play across the board.

That said, I think the question could be reversed. Why bother using stainless cladding on high end knives? A reactive cladding isn't that different from a reactive core steel to clean and maintain. Yeah, some of them can get a little funky, but many of them don't, and if a knife is properly wiped and stored rust isn't a big issue. You might get a little speckling now and then, but a little Comet fixes everything up in seconds. If the knife isn't properly wiped and stored, the core is going to rust anyway. The sort of person who buys these knives should be able to or willing to learn to maintain them, sharpening and cleaning included. And it really does make thinning easier, which leads to easier top notch long term performance.

I don't find stainless cladding to be a huge feature these days. It's nice and in a vacuum I would prefer it, but it is certainly not essential, and many smiths are I'm sure happy to save everybody a dollar and themselves a little frustration. I use a few reactive clad knives, including a Moritaka, just as I use my stainless clad knives.
MisoSatisfried
Posts: 827
Joined: Sun Feb 05, 2017 3:38 pm
Location: Minnesota
Has thanked: 32 times
Been thanked: 20 times

Re: Why use reactive cladding on good knives?

Post by MisoSatisfried »

All I know, is that I wish my Fujiyama B2 was clad in stainless, ha. Worst iron cladding I own, which is a shame on such a lovely knife! The Doi puts it to shame as do my others including the W2 Fujiyama cleaver. I agree and assume it just makes the smiths life easier.
I'm Dave. I don't take myself too seriously and you probably shouldn't either.
User avatar
limpet
Posts: 525
Joined: Fri Jan 27, 2017 2:34 pm
Location: Sweden

Re: Why use reactive cladding on good knives?

Post by limpet »

+1 on making it easier for the smith when it comes to handmade/forged knives.

I may remember this wrong, but at an event Yu Kurosaki mentioned that aogami super core steel with stainless cladding was very popular with the customers, but demanded more work from the smith during forging. Aogami super I guess is a bit more difficult to get right in general and stainless cladding cools down faster than reactive cladding. More room for error.
Robstreperous
Posts: 2497
Joined: Fri Jan 27, 2017 11:46 am
Location: Long Island
Has thanked: 120 times
Been thanked: 453 times

Re: Why use reactive cladding on good knives?

Post by Robstreperous »

Hey Lepus... Great news... Now we can disagree a little bit. :lol:
Lepus wrote: Thu Oct 19, 2017 9:54 pm A reactive cladding isn't that different from a reactive core steel to clean and maintain.
Some of them aren't all that different to maintain. Example, I've had very few problems with my Shimo and Yuki or even my Takedas for that matter.

But take a look at this iron clad from this weekend. This particular knife had about 2 months worth of nice blue patina on it.

Used it to cut exactly 1 medium-large tomato. Wiped knife. Scraped board. Put knife back on board. Below is what happened after 5 minutes. Yeah I know not the best practice I'll get better -- but still this never happens with my other carbon clad, semis or stainless.

Image
Post Reply