Tuning composite laminates.

[Carlos]

I've heard that Spyderco already has its G-10 laminates tailor made for its use, and this idea goes more towards Spyderco's regular G10 knives, than to future "F1" series clipits.



As we know epoxy laminates can be made all with one structural material, like G10 (fibreglass), or with different layers of different materials, G10, CF, Kevlar, even honeycombs of aluminum. On top of that the direction of the fibers can run in different ways to alter the behaviour of the finished laminate.



For instance one problem with CF seems to be its brittleness. This is why when laminates are used for hull construction in competition level boating (to maximize toughness), the highest tech option is a hybrid of kevlar and carbon fibre, with hybrids of kevlar and fibreglass being the next step down.



It seems that for knife handles toughness should be as important as rigidity. A composite that fractures and splinters under shock (say, if dropped), probably isn't ideal for hard-use knives (this has been reported in some cases with pure CF). In theory it might be wiser to tailor a hybrid that combines toughness with the desired rigidity and low weight.



Has Spyderco ever considered going beyond the use of tailor made G10 laminate, to a tailor made "signature" hybrid laminate (also as a flat sheet)? Perhaps a fiberglass/carbon fibre hybrid, with the fiberglass on the outer (grip) side for shock resistance, and with CF on the inner protected side to lower weight and increase rigidity? In theory a s-glass/carbon hybrid might be a viable general "step up" in performance for an acceptable premium.



And with the possibility of molded CF laminate in the future, would a hybrid of kevlar and carbon make more sense than carbon alone?



One more idea: Has there been any experimentation with honeycomb based laminate constructions for handle designs?This would probably only be of use in a molded construction, but in theory a formed handle slab with a core of aluminum, carbon, or Nomex honeycomb would maintain the desired strength and rigidity while lowering weight even further.



http://www.hexcelcomposites.com/products/honeycomb/index.html



Any thoughts? I'd be suprised if Spyderco hasn't already done some experminentation along these lines.



BTW, any progress on the MMC front?

[sal]

Hi Carlos. We have tried some kevlar / carbon fiber laminates in the past. They worked well, though we didn't do breaking tests.

They are very difficult to machine. The kevlar is difficult to cut and ends up wrapped around bits.

It might be easier when it's formed. we'll see.

MMC?

sal

[Carlos]

Hi Sal,

MMC = Metal Matrix Composite. I'll take that as a &quot;No we haven't played with it yet.&quot; <img src="wink.gif" width=15 height=15 align=middle>

[BladeWalker]

Is the G-10 on my 'Standard' the kind of material they use in PCBs (Printed Circuit Boards)?

I once cut the ends off some G-10 PCBs on a big band saw in a machine shop at work.
Later, when I told the machinist that I had seen sparks flying off the blade, he told me
to go get a new blade, the old one was totaled. He told me to Never cut that stuff
on his saw again! Tough stuff, I guess..

Rich&lt;&gt;

[sal]

Hi Carlos. We did look into it. The basic material for their matrix is alumina. We use alumina quite a bit in our ceramic sharpeners (they are 94% alumina). It was my guess that the strengths were in durability and wear resistance. The drawbacks would be in tooling and weight. So at this time, I would rather exend my energies in the Carbn fiber and other lighter materials.

Hi Bladewalker. Yes it is a very similar material. We're making up some special layups of the material for knife needs. The material is exellent for many purposes. It IS tough.

In the late 60's I owned and operated a printed circuit board prototype facility in Canoga Park, California. I made aerospace prototypes for the majors in the area. At that time, I used the material for everything from art (etched) to small structures needing strength and durability.

sal

[Carlos]

Hi Sal,

Good to know. Have you looked into magnesium, and magnesium-based MMC?

Where does Magnesium weigh in relative to CF and G-10? I already knows that it weighs less than aluminum, but vs. the laminates? My understanding (possibly erroneous) is that MMC forms of magnesium attenuate some of the problems of regular magnesium. Though it will likely have the same tooling issues as aluminum MMC -- perhaps its better just to focus on CF?

[sal]

Carlos. We made a knife about 10 years ago with a magnesium handle and a ceramic blade, under the TAK label. Tak Fukuta made the piece for us. The Magnesium was interesting. Light, pretty and medium strength.

Since Im the primary source of &quot;chase&quot;, CF is my current responsibility. Once we get that working like I want, then we'll continue the chase.

I noticed that another manufacturer just advertised a knife with a magnesium handle. I don't remember who it was.

sal

[Carlos]

Hi Sal,

You must be having fun in R&amp;D with something new to play with always on the horizon. Since you are still developing CF, do you ever see CF becoming feasible for regular production knives (in the place that G10 holds now), or will it be limited to sprints and the &quot;F1&quot; level for the forseable future?

A bit more for the future:

&quot;Magnesium Metal Matrix Composite: Magnesium alloys, primarily due to their low weight, are progressively being used in a wide range of applications. Other distinct characteristics of magnesium alloy such as easy machinability, excellent castability, good weldability, superior damping characteristics and availability encourage the designer to consider this material as an alternative to materials such as aluminium. However, many modern technologies require materials with unusual combinations of properties that cannot be met by conventional metal alloys. This is where metal matrix composites (MMCs) come into picture. The addition of hard ceramic (carbon fiber)into magnesium will produce a low density, strong, stiff, abrasion and impact resistant material.&quot;

[seth]

Carlos,

Just wanted to say that I enjoy your posts about all the exotic materials. I have to do research to grasp an understanding of the three letter acronyms. Seriously, your knowledge about materials is informing and intresting.

Keep tossin' those exotics.

Seth