We’ve recently introduced the Jende Kangaroo and Leather strops on color coded acrylic to our lineup. One of the questions that will inevitably be asked is “which one is better?” As usual, the answer is “it depends”. They are both excellent mediums, and this article is designed to allow you to make a better informed decision about which is better for you and your particular needs.
Jende Leather Strop (acrylic side)
Kangaroo and Cow leathers are both tanned animal skins, In this case it is vegetable tanned, which is basically untreated with any oils, waxes, etc.. It’s the most natural foundation which can then be used as a clean, final strop or be loaded with pastes, sprays, compounds or emulsions of your choosing. Cow leather has a much longer history of use for stropping, with Kangaroo leather only becoming more accessible since Crocodile Dundee first appeared in the 1980s. 😀
Jende Kangaroo Strop (acrylic side)
Ounce for ounce, kangaroo has about 10 times the tensile strength as cow leather, meaning a thin 1mm strip of kangaroo is about as strong as a 2-3mm strip of cow leather. This translates into less compression of the kangaroo strop over the cow strop, which can be advantageous in certain situations like straight razor honing. But the compression of the cow leather can be more suitable to matching the shape of convex edges.
In order to better describe more of the differences between kangaroo and cow leather, we need to look more closely under the microscope. Here’s a side by side macro view of the Jende cow and kangaroo leathers. Pictures are taken with a Veho 400x and the actual resolution is 1.3mm wide x 1mm high.
Cow Leather, Macro
Kangaroo Leather, Macro
At this level, the cow leather looks very consistent and smooth. There is what’s best described as a “spotted” texture to the leather, but it seems flat, overall. (It reminds me of the surface of painted drywall, actually.) The Roo, however, looks like an army of ants are embedded in the surface. These are the hair follicles of the skin. Overall, the surface looks smooth, even with the contrast of the black follicles. Honestly, there’s not much difference to be seen between the two skins here.
Where things really change are at the micro level. This resolution is 1mm wide by 0.75mm high.
Jende Leather Strop, Micro
Jende Kangaroo Strop, Micro
The spotted surface of the cow leather reveals a smooth surface with raised polyp-shaped mounds. The kangaroo leather shows a smooth surface with divots where the hair follicles are. It is this difference that really influences the the way each strop works.
My theory is that he raised polyps on the cow leather will come into contact with the blade when stropping, making the strop more aggressive but arguably slightly less consistent. If you were to load the strop with an abrasive, the abrasive would leave deeper scratches at the polyps and more shallow scratches in between. Again, arguably more aggressive but less consistent.
The divots on the kangaroo leather do not interfere with the stropping action of the rest of the surface of the strop, meaning you get more consistent contact with the strop when stropping. When the kangaroo is loaded with an abrasive, the contact between the blade and the strop is much more constant as well since the abrasive fills in the gaps. The catch here is that this could be considered less aggressive since the surface scratches are not as deep, but because more edge is in contact with abrasive throughout each stroke, it could still be described as as aggressive since there is more shallow depth of scratch per stroke, but a whole lot more of it. It’s a different kind of aggression.
So what does all this rambling mean? Well, based upon the picture evidence, there is a strong argument to be made that the polyps of the cow leather make for a more aggressive stropping medium and the divots of the kangaroo make a smoother stropping medium. This is the simple answer, of course, and doesn’t factor in things like stropping technique and pressure. But is does remain a constant that the cow leather has raised polyps and the kangaroo has divots, and this is the information needed to begin making an informed decision as to which stropping medium is better suited for your needs.
To give an example, a 2K edge on a hunting knife can get more out of a cow leather strop since it will push the edge back into position with more force. That same cow strop loaded with a 4 micron (4K) Jende emulsion takes the knife edge up a notch while still being aggressive enough to maintain the edge between sharpening sessions. On a straight razor, a kangaroo strop will push the fragile edge back into a more uniform position. The same kangaroo strop loaded with 0.25 or 0.10 Jende emulsion will abrade the edge of the razor more evenly, thus minimizing microchipping while keeping the scratches very consistent. You can just imagine the possibilities from here!