carbon fiber blade test

Very cool review :thumbup: I've always been curious about CF knifemaking.

Just a quick question, how is the carbon-fiber attached to the steel? Is there some kind of laminating process, or adhesive, or what? And how does it wear compared to steel? I know it's a bear to machine, but I wonder how the area where CF meets metal is going to look after several years of use.
 
good questions

the steel edge has fingers ground into it so that the cloth has a mechanical lock to the edge. The laminating process involves vacuum soaking and a high pressure gluing press.
Low viscosity epoxy with long working time are required.

I have one in continuous service, first as a pass around, currently in the shared kitchen of 2 bachelors (one summer it outside for months). It has no significant wear. My d2 blades look like crap after this treatment.

You are right to wonder about the exposed junction where the steel edge ends and the fiber composite begins. Under destructive testing this area does erode, but the edge is thinner and exposed to more stress and wear, so that's really the area of concern.

Longevity and toughness are not what these things are about... think about how long a solid steel blade of the same mass would last. These things are light for their size, and very little steel is exposed to corrosion.
 
Very interesting,

What steel are you using as the cutting edge? How far back into the blade does it extend (i.e. how many sharpenings before there's no edge left)? Do you think this could work as a blade for a folding knife, would the carbon fiber hold up in the pivot area?
 
thanks!

more good questions!

there is usually about .230" edge, so that would be a lot of sharpening before failure (i guess it would have some radical serration pattern after that!). None of my personal knives have ever been sharpened that far back, and I've been sharpening for over 30 years though I understand a chef or butcher might put that kind of wear on. On the other hand, for a pro there is the weight savings over years of use

the carbon fiber will not last long in the pivot or lock area... wear inserts would have to be used there, that would reduce the continuity of the fibers (it's my own custom lay-up but there are limits) and reduce strength. Carbon fiber laminates are strong for their weight because they are large for their weight, separating the tension and compression forces. For a compact mechanism like a folding knife pivot and lock we need to stick to materials that are strong for their size. I guess you could have oversize pivots and such but I typically only made lockbacks... hmmmn now you've got me thinking... maybe after Blade show I'll look into it...

I currently use M2 for the edge, much better than the stainless in the prototype. I scaled it down a little to 4.5" cutting edge, less than half an oz of metal in the entire knife, and very little is exposed for corrosion

there needs to be an electrically insulating layer between carbon fiber and any metal to avoid galvanic corrosion (theoretically). I always use some super thin glass twill fabric for this during the lay-up, though on a couple early ones I didn't and they haven't suffered yet
 
Thanks for the info wnease :thumbup:
I've been trying to get into knifemaking for more than a year now, but I keep getting distracted by other priorities - hard as it is to get into knifemaking, breaking into film is even harder :confused:

So for now I'm just asking as many questions as I can, so that when I finally have the necessary time and capital, I'll have all my bases covered.

Thanks again, and congrats on making a lovely knife :)
 
no good! i'm from alberta myself but live in ontario; the ckg show is in toronto (which makes sense, it IS the centre of the universe)...

my advice to starting knifemakers is the same advice i received from wayne goddard... start making knives

personally i started by hacksawing and filing barstock, then a 1 by 30 sander, then a drill press, then an angle grinder... must have made a hundred before getting a 2 by 72
 
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