Cratex for convex edges?

Sounds perfectly feasible to me. I didn't know Cratex came in strips like that, but it's been years since I've looked. Basically it's the same thing as the mousepad/sandpaper method. Just that in this case, the "mousepad" is the sandpaper.
 
I had no idea the blocks existed, awesome! Ive used several different types of rubber wheels in the past as a Diamond setter/production jeweler and somewhat familiar with Cratex but the blocks must me a fairly recent thing.

The idea in the video may not strike me as something I feel compelled to try as I'm pretty happy with sharpening convex on stones but I wouldn't discount it. Give it a try and report back.
 
I'd personally not recommend that method since the rubber would wear down pretty quickly and start thickening your edge angle. Cratex is handy stuff for surface finishing applications, but it would be a fairly poor sharpening medium.

Cratex blocks have been around for quite some time, and Klingspor makes some as well. They're just more of an industrial product that's not commonly encountered unless you work in an industry that uses them.
 
Based on the mfr's description of them, these remind me of the 'rust eraser' blocks, with those having SiC grit bound in a rubbery matrix. I've experimented with those, to see how they'd touch up an edge. As mentioned by FortyTwoBlades above, the rust erasers do erode very quickly, sort of conforming to the shape of the material they're abrading, which makes edge-rounding & thickening issues more challenging to avoid.

I could see how the material would be handy for finishing and/or shaping the primary grind behind the edge. But, for the edge itself, I'd always prefer to finish that on something much firmer, like a stone, or at least with something like hard-backed sandpaper for convexed edges.
 
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I got one of their rectagular blocks in the early 90s so they have been around for awhile. Doubt it would be any use for knife sharpening, I don't think I have touched mine in 25 years. It is a coarse version and is only good for polishing, too soft to cut an accurate bevel.
 
I used to be in touch, years ago, with a very accomplished wood carver from Britain who would create highly detailed, ornate and elaborate works. He used Cratex to sharpen his carving knives and recommended its use to me.

I never ended up pursuing it as my own whittling projects were anything but highly refined.
 
I use it to correct / make brushed finish on kitchen knives but never sharpened with that. it seems too soft to create an edge.
 
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