How to Sharpen a Knife in the Wild (Use this Little Known Rock Method)

When it comes to survival tactics and gear, there is little that survivalists can agree on. But there is one thing that all survivalists say for certain: You need a survival knife with your supplies.

Having a survival knife means you can make cordage, make shelters, baton wood, and skin animals much more easily.

But a dull survival knife isn’t going to do you much good.

A dull survival knife can be very dangerous! When a survival knife is dull, it can slip off an object instead of cut through it. The knife blade is still sharp, so it can cut you as it slips off. This is why dull knives are responsible for more injuries than sharp knives.

One smart solution is always carrying a sharpening tool in your survival supplies. Read more about the best survival knife sharpers.

But, if you find yourself in the bush and need to sharpen your blade, you can use this little-known method for sharpening your knife.

DIY Whetstone from Sand

When sharpening a knife with natural materials, you must know that natural rocks are NOT uniform in hardness.

Rocks contain various minerals, each of which has a different grain size and hardness.

So, if you grab just any rock and try to sharpen your knife with it, you could make nicks in your blade. A jagged knife blade doesn’t help you much more than a dull knife blade!

With this in mind, the secret to sharpening your survival knife in the bush is to find something with a uniform hardness and fine grain. This sand method works well.

Step 1: Find or Make Sand

Sand is very fine grain, so it works well for sharpening a survival knife and getting a uniform edge. This is something that most rocks will not produce.

If you can’t find any sand, you can make sand by gathering small stones (preferably from a river) and crushing them into a pulp with a bigger stone. The stones need to be crushed to the point that they become mush.

Step 2: Get a Live Tree Branch

Now, you need to snap off a tree branch. It is essential that the tree branch is still alive because it will contain moisture inside of it. The moisture acts as a lubricant while also helping to trap the sand within it.

Shave the bark off the branch (careful, because your survival knife is dull!). The branch needs to be at least 3 inches in diameter. The larger, the better. If possible, carve down the branch so it is flat. The flat side will hold the sand better and be easier to sharpen your knife on.

Step 3: Rub the Sand into the Branch

Put your sand mush onto the branch. Try to rub it in there pretty well. Don’t overdo it, though. You don’t need to sand down your fingertips!

You now have a “whetstone.”

Step 4: Sharpen Your Knife

Rub your knife back and forth over the sandy branch just as you would with a whetstone (at about a 30-degree angle). You’ll have to reapply more sand mush multiple times.

Alternative Method

A much more intensive way of making this is to make your own bushcraft sandpaper. The video below explains how to do it – you’ll need pine sap resin. You can then put the sandpaper on a board and will have your own sandpaper whetstone.

6 Other Ways to Sharpen Your Survival Knife in the Bush

Again, I want to emphasize that you can’t just grab any rock you find in the bush and use it to sharpen your survival knife. The rock needs to have a uniform grain size and hardness. But, in a pinch, you can use these other methods for sharpening your knife in the bush.

1. A Flat, Smooth River Stone

River stones are suitable for sharpening knives because the water has worn the surface down to a very small grain, which helps produce a uniform edge.

If you can find it, sandstone is also suitable for sharpening a knife in the bush because it has a reasonably uniform grain.

Remember always to keep the stone wet while you sharpen your knife with it! The stone will take away small metal shavings from the knife. These shavings are called “swarf.”  The water will help carry away the swarf so your blade doesn’t continually go over it and get nicked.

2. Two Rocks

Another excellent solution for sharpening a knife in the bush is to take two round rocks (uniform in size and hardness) and put them together to make a V run. Run your knife back and forth in the space between the rocks to sharpen the blade.

3. A Piece of Glass

I usually hate that there is trash everywhere in nature. But, when SHTF, we will all be glad that the world is filled with junk. With creative thinking, the garbage can be used for survival purposes – including sharpening your knife.

Find a piece of glass with a flat edge. Rub the sharp side of the glass over the knife blade at a 30-degree angle until it becomes sharp.

4. Another Knife

An “old school” method of sharpening knives is to rub two knives against each other. You might have seen your mom or grandma do this.

It takes a bit of practice to sharpen knives this way. You’ll have to hold one in each hand and stroke them away from each other. The key is to glide along the entire length of the blade with an equal amount of pressure. Stroke each knife at a 30-degree angle, first doing one blade side and then the other.

5. Cement or Brick

You can use cement or a brick to sharpen a knife. It will scratch up your blade side to all hell and won’t produce a sharp edge – but it will get the job done, so your knife isn’t dull anymore.

6. Your Leather Belt

If you have a leather belt, you can use it to strop your knife. This won’t get it very sharp, but it will help to remove any burrs which might have gotten on the blade and improve its cutting ability.

Do you know any other ways to sharpen a knife in the bush? Let us know! Join the discussion in the Primal Survivor Facebook group.