A sheet of sandpaper and a flat, hard surface are all you need to sharpen any knife. It is really easy and simple. Kitchen knives get dull very quickly from cutting on ceramic plates, jostling in the dishwasher, and everyday use. This method can be used very quickly in the kitchen. Remember, a sharp knife is a safer knife.
Get a sheet of #180 grit or #240 grit “Wet-or-Dry” silicon carbide (black) sandpaper. These can be found at any home improvement store, or even Walmart in the Paint-Wallpaper section. Sometimes these are sold in “Variety Packs” with several grits, about $3. One sheet will last for months.
Lay the sandpaper grit side up at the edge of a hard flat surface (table, counter top, or cutting board). This will allow you to hold the handle firmly and sharpen the entire edge.
Firmly hold the knife by the handle and slide the edge across the sandpaper like you are slicing thin layers off the sandpaper. Always move the knife in that direction, “on to” the sandpaper, never backwards, in circles or straight along the edge. An angle of about 20° is best. Do not use a lot of pressure, just steady, even strokes—about like slicing a raw Irish potato.
Sharpen both sides of the blade the same way and the same amount. Alternate sides: Take maybe three strokes on a side, then change.
For knives with curved blades, raise the handle slightly while sliding the edge across the sandpaper so that you sharpen the entire length.
Put a few drops of water on the sandpaper before you start. This keeps the edge cool and makes the blade slide more easily. Rinse the paper and blade when done.
180 and #240 grits work fast and give the best edge for kitchen knives that are used to cut vegetables and meat. Higher numbers (finer grit), and lower numbers (coarser grit) do not work nearly as well.
This will work on any type of blade, straight, curved, serrated (steak knife), or scalloped (ham or bread knife), even electric knives.
The technique will work better as you get used to doing it. You will find your own methods and improve on these, too. The first time you try it will be the hardest, partly because your knives may really need sharpening. Then you will get used to using sharp knives and want to keep them sharp with light “touch-ups”.
Fold the sandpaper in half and store it in a cabinet against the side. Doesn’t take up any room and is always handy.
It is best to cut on a natural wood cutting board. Natural wood has antibacterial properties and the soft surface will not dull knives nearly as quickly as cutting on ceramic, plastic, or metal.
Put the knives in the dishwasher “point down” in their own utensil compartment without other utensils. With the points stuck in the small openings in the bottom, the knives will not move around and rub against each other as much and the sharp edges will not become dull so quickly. This practice also makes it safer to load and unload the dishwasher.