What part of the San-Mai recipe are you going to use it for?

Karl,

I'm looking to use it as the outside layers, on either side of a 1084 core.

Thanks,

Dave

Knife making is a creative play ground and you can use whatever components you choose. Keep in mind that the traditional method of San Mai is: "the technique offers a practical and visible advantage of a superb cutting edge of modern Japanese knife steel, with a corrosion-resistant exterior. In professional Japanese kitchens, the edge is kept free of corrosion and knives are generally sharpened on a daily basis. Corrosion can be avoided by keeping the exposed portion of the non-stainless portion of the blade clean and dry after each use."

Carbon steel on top of carbon steel will offer very little in terms of VISIBLE variation or hardness.

Many folks who also use like 15N20 on the outer layers are simply making a three layer pattern welded blade. Sort of an ultra-low layer count Damascus, and not San-Mai - by definition.

That said, use whatever you choose. The forge is yours.

Karl,

Thank you for your comments. I have been playing with 15N20 clad 1084 san mai and it gives a good visual. I wanted to try a more traditional approach with a softer steel clad harder steel core. I can find A36 steel but wanted something that would harden a little.

You made a good point about medium carbon steel layers on 1084 not giving much of a visual demarcation between the steels. I suppose I could get around that by using 15N20 as my core layer. But in either case, first I need to find a source of medium carbon steel, such as 1035.

Thanks,

Dave

My understanding was that the term San Mai translated to "3-layers" as regards knife making. Perhaps it makes sense to have more corrosion resistant outer layers for kitchen knives, but I don't believe that is exclusive to the technique (most likely some marketing convention for a particular line of knives). Needless to say it is much more difficult to laminate stainless on the exterior of your high carbon billet.

Depending on your technique you can get some carbon migration between the layers as well, so going with medium carbon isn't that bad an idea, but certainly San Mai has been done with low carbon cladding (as well as wrought iron for that matter). Some folks use a layer of pure nickel sheet between the low carbon cladding and high carbon core to address the carbon migration issue, but that technically is no longer San Mai, as I understand it, since there are now 5 layers.

One of the big issues I've found with the technique is the tendency for warping or even splitting of the core steel due to differing thermal expansion and hardening changes between the two materials. That is where a 15N20/1084/15N20 San Mai sandwich might be the easiest to accomplish.

1045 is available in plate form from a variety of metal suppliers. Of course you can just get some 1" square bar or round bar and forge it down to the thickness and width you need...

I like to help folks understand the actual reasons and advantages of methods of blade construction. Today, the greatest advantage of this construction is in appearance, I personally find the wrought iron cladding even more attractive than the stainless. Functionally, the softer cladding doesn't offer any advantages, forcing a much lower yield point onto a normally more resilient core, and it is quite similar to hamons in the aesthetic vs performance misunderstandings. Historically, this type of construction was done to conserve the less abundant steel by supplementing the blade mass with more readily available iron. As soon as steel making advanced to the point that entire blades could be made from it, this method of construction was rendered to a few styles for the sake of tradition. You can stretch a little, thin, sliver of high carbon steel a long way by sandwiching it between two pieces of other material and make three or four knives, rather than one. There will be some carbon diffusion between the layers, but that is why it was done san mai, to stick just three layers can be done in one or two welding heats, and thus greatly limit the carbon loss from the core to the cladding. Folding and rewelding would do the opposite, and homogenize the carbon content, thus defeating the high carbon advantage.

Dan, Kevin,

Thank you for your input!

Dave

Its more work but technically railroad spikes are medium carbon steels, A36 is a medium-ish but has some issue, and you can sometimes find 1045 on NJSB.com.

|quoted:

I like to help folks understand the actual reasons and advantages of methods of blade construction. Today, the greatest advantage of this construction is in appearance, I personally find the wrought iron cladding even more attractive than the stainless. Functionally, the softer cladding doesn't offer any advantages, forcing a much lower yield point onto a normally more resilient core, and it is quite similar to hamons in the aesthetic vs performance misunderstandings. Historically, this type of construction was done to conserve the less abundant steel by supplementing the blade mass with more readily available iron. As soon as steel making advanced to the point that entire blades could be made from it, this method of construction was rendered to a few styles for the sake of tradition. You can stretch a little, thin, sliver of high carbon steel a long way by sandwiching it between two pieces of other material and make three or four knives, rather than one. There will be some carbon diffusion between the layers, but that is why it was done san mai, to stick just three layers can be done in one or two welding heats, and thus greatly limit the carbon loss from the core to the cladding. Folding and rewelding would do the opposite, and homogenize the carbon content, thus defeating the high carbon advantage.

To clarify, Is San Mai the same as what Nordic countries do with laminated blades?

|quoted:

To clarify, Is San Mai the same as what Nordic countries do with laminated blades?

Currently, or historically? By historically, I mean 1000 years ago.

Either will do to as an answer.

From the reading and research I've done on the ancient Nordic construction methods, it was not what we call San-Mai today. It was more like what we call a multi-bar stacked construction.

San-Mai is more like making a 3-layer billet of Damascus, doing zero patterning or manipulation other than welding them together, and forging a blade out of it. The outer layers are typically lower carbon, iron, or in modern methods, stainless steel. All three layers extend from spine down toward the edge. When bevels get ground in, the outer layer terminations move back upward toward the spine and reveal the high C layer at the edge. The "jacket" of non-edge steel goes from spine down to where it has been ground through. Looking at the spine, you see all 3 layers.

The ancient Nordic blades were more like taking a couple of bars of different material (some may have been multi-layered PW steel like twists), and stacking them on top of each other. The Nordic method usually put a lower carbon steel or iron bar along the entire spine, and a higher carbon steel along the edge. There may have been one or two PW bars in between. When looking at the spine, all you see is a uniform bar of material.

Both methods produce a visual "line" between the different layers, but the construction is different in process.

How does the ancient Nordic blade construction compare to ancient Japanese blade construction? I'm more interested in knifes rather then swords.

I'm not really qualified to comment on Japanese blade making. I haven't done the research required. Hopefully, someone can answer that.