Why Laminates?

[Doc Dan]

I seem to remember something about that the two steels had to have compatible properties, for heat treat, and etc. But I may not have that last part right. Does anyone know anything about the compatibility requirement?

[tripscheck'em]

Laminates are for increasing corrosion resistance. Super Blue rusts easy, so you laminate it to prevent rusting at the pivot, which would otherwise require a user to void the warranty to clean the knife. Same for HAP 40 and ZDP-189, all these steels need lamination in folders, otherwise the pivot would get so clogged with rust that you couldn't open the knife, that is what is happened to my ZDP-189 Endura just from pocket perspiration while working.

I never understood the anti-laminate crowd here.

[aesmith]

I didn't think about the pivot issue. Is the blade still laminated at that point, I mean does the hole go through three layers, or is the HAP40 (or whatever) only present along the cutting edge?

[jabba359]

I didn't think about the pivot issue. Is the blade still laminated at that point, I mean does the hole go through three layers, or is the HAP40 (or whatever) only present along the cutting edge?

It's a laminate through the entire blade, so the pivot hole passes through laminate, core steel, then laminate. That means there is some exposed Super Blue/HAP40/ZDP-189 in the middle layer of the pivot.

[bearfacedkiller]

The tang which contacts either the washers or the liners is cladding but the pivot hole itself does pass through all three layers. I have used and carried a super blue Caly3 which does not have cladding a ton and it is still as smooth as glass. While clad blades do in fact provide corrosion resistance that is certainly not the only reason that they are used. It is my opinion that tradition is a big part of why they are used along with corrosion resistance, differential hardening and reduced grinding time/cost.

[aesmith]

Actually thinking again, is corrosion at the pivot even a factor? The upcoming Military in 52100 isn't clad.

[bearfacedkiller]

I have both the Caly3 and Caly3.5 in unclad super blue and my pivots and tangs are just fine. Keep the pivot area oiled and you will not have any problems. If you run the pivot without lube and you don't keep the knife clean then you will likely have problems. Carbon steel knives have been around much longer than stainless knives and people got by just fine. I have 30 year old carbon steel pocket knives that are still in great shape. This is not meant to devalue the benefits of modern stainless steels but their existence does not make carbon steels obsolete and with a small amount of effort carbon steels can be maintained quite well.

I have both clad and unclad blades in multiple steels and I like them both. I do not believe that there is a right or wrong answer when it comes to clad blades. I guess it is just personal preference. It does amaze me how strongly many people feel about it one way or the other. The way I see it they both have benefits and in the end it is the edge that does the cutting and cladding has no effect on cutting performance.

[jabba359]

Darby covered it pretty well. Keep the pivot area clean and dry, using some lube/corrosion inhibitor on occasion, and you shouldn't have any problems.

[Blerv]

The amount of corrosion even Superblue laminate would need to degrade tolerances or rust out a pivot be insane.

If that happens I would just stop walking around with pockets full of rock salt.

[JD Spydo]

I seem to remember something about that the two steels had to have compatible properties, for heat treat, and etc. But I may not have that last part right. Does anyone know anything about the compatibility requirement?

I think EVIL D had it right>> I do believe it's more about corrosion resistance than it is aesthetics. But I do agree with some of the guys that it does have an appealing look to it as well. I've also wondered if added tensile strength was also a primary objective?

The very first Spyderco laminate I got was when they released their first ZDP-189 blade laminated with 420-J2. That was back in 2005 if my memory serves me well. That was one of my all time most used folders out of all my Spyderco EDC rotation arsenal. With that full flat grind Caly Jr. it would take an unbelievably sharp edge. And the laminate would polish up well too>> that way you had the best of both metallurgical worlds :cool:

[Kenakth]

I've also wondered if added tensile strength was also a primary objective?

My first thought is that it wouldn't make much of a difference in thin folding blades, and that the benefit would be much more noticeable on a thicker fixed blade that was put through heavier use/had lots more lateral forces applied. I'd be very interested to see if there's been any testing done in medium-sized folders (~3.5" blade) on that matter.

[Bill1170]

A clad blade typically has a hard core with softer cladding. This actually reduces the bending strength, but what's important is how it increases toughness, or work of fracture. The clad blade is much less likely to shatter than a very hard monosteel blade.

[Brock O Lee]

I have read somewhere, I think in one of Cliff Stamps posts, that a soft laminate would make a blade easy to thin out or regrind when using waterstones. If I remember correctly, this sharpening practice is very common in Japanese knife culture. On a FFG blade that would mean to lay the blade flat on the FFG on the stone. I have done this with both a Superblue Stretch and Superblue Delica, and a few others.