You arrive in camp and begin using your blade. It is late and, as a result of both the darkness and exhaustion, your hand slips while cutting—and you damage the edge. Worst of all, you realize you did not pack any sharpening provisions, and you anticipate using your blade often while you’re out. You have few options: Pack up and go home; keep using your knife, potentially further damaging the edge and making your work harder; or restore your edge by utilizing nature’s resources.
Nature, after all, has all you need to keep your blade in working order. From stock removal to honing and polishing, you can generally find what you need in creek beds and the remnants of campsites to sharpen your blade in an emergency situation.
Most people assume all you need to do to sharpen a knife is find a river rock. There is more to it than this. Rocks found in the center of the river are generally the smoothest, because water runs over them most often. As you look from the center of the river out, the rocks will become grittier as a result of spending some time underwater and some time pocked by exposure to the air and elements.
“Nature … has all you need to keep your blade in working order.”
Start with a rock that has an aggressive texture (think concrete) and move to progressively smoother rocks. The coarser rocks should make it easy to remove rolled steel. As you refine the scratches on the steel, check to make sure the edge is still uniform. Run the blade in a circular pattern on one side until you see the wire (a thin layer of steel removed at the edge) form. Flip the blade over to the other side and repeat the process until you see it again. Alternate your passes on the stone, one side to the next, until it has a consistent grind.
If river stones are unavailable, smooth rocks can be cracked open to expose the texture inside. Drop a larger rock onto another over a rock surface. These rocks can be rubbed against each other to change the amount of grit desired. If nothing else is available, sand can be embedded in a wet log, creating a large sharpening strop.
“You have few options: Pack up and go home; keep using your knife … or restore your edge by utilizing nature’s resources.”
Honing is the process of realigning the carbides at the edge of a blade (the wire) to create a noticeably sharper edge. Honing doesn’t remove material, but it is an important step in the sharpening process. Professional chefs use a steel to do this prior to carving.
Without an available steel, the outdoorsman can use broken glass to hone a blade. Glass is hard, but brittle, and when a steel blade is drawn across it, it acts like a honing steel. This method works well in non-emergency situations, too. Alternatively, a coffee mug, the edge of a car window, the rim of the inside of a toilet tank lid, or a porcelain rod will also accomplish this.
“ … stropping is best accomplished when the belt is placed perfectly flat on a surface.”
If glass is not available, the outdoorsman can use the inside unfinished section of a leather belt to strop the blade. The buckle can be passed over a log and the tail end can be passed through, creating a hitch. The slack is tightened, and the blade is positioned on the strop with the flat lying against it.
The spine is raised off the belt about the same thickness of the tang. The blade is drawn, spine first, over the leather belt in the same manner a barber would strop a straight razor. The amount of pressure should be about the same as one would use when shaving with a safety razor. It is important not to roll the edge at the end of the stropping motion; instead, trail off the belt. Also, stropping is best accomplished when the belt is placed perfectly flat on a surface.
A polished and clean blade will perform better than one that is dirty. The flats of the blade can be polished using hardwood charcoal from campfire remnants. Used dry or with just enough water to make a slight slurry, the hardwood charcoal is not as hard as the steel and won’t damage the blade.
Sand can also be used as an abrasive for stubborn substances on the blade—but at the expense of leaving some scratches behind.
“ … sand can be used as an abrasive for stubborn substances on the blade—but at the expense of leaving some scratches behind.”
Should a more subdued finish be desired after honing, a patina can be forced onto a carbon steel blade by exposing the steel to the natural liquids found inside trees that contain sugars. Once you return home, that patina can be forced even more by inserting the knife into a potato overnight, coating it in mustard, or submerging it in vinegar.