... a very, very sharp knife.
: But not a straight razor!
well, seriously, that and a straight edge. that's it, that's all. I use an "Olfa" knife with a new blade in it. And my straight edge is exactly 2 1/2" wide, which just happens to be my preffered width. The crunch comes in finding a section of leather that doesn't show any wrinkling, or scars, or any kind of defect that could interfere with the edge of the razor. If you can, try to cut the lengths so the grain runs parallel.
I'll post a couple photo's so you can see what I've done to hand 'em. It's a pretty hokey system, but it's effectice.
Well. here they are.
You can see that the hangers come from an old duffel-bag strap. Cheap, and I've got a couple crappy old ones kicking around. they work surpprisingly well, though they look kinda crappy. The rivets are just those rivet thingys you can get at most craft stores, come with a little anvil and a punch type thing for setting them, for less than $10.00
In the one photo, I've tried to show some fat wrinkles that would normaly never make it into a strop, but that's the one I made from the last of that piece of leather to experiement with the coti slurry on. The wrinkle are outside of my normal stroke so they won't interfere.
(The other is the one I was going to send to you, Louis... sure you don't want it?B) )