When struck against steel, flint will produce sparks, which when directed onto tinder, can be used to start a fire. When the hard flint strikes the steel, it shears off a small sliver of steel. This tiny particle is heated by the impact between the flint and steel and burns with oxygen from the atmosphere.
Flint – Flint can be found in many parts of the country. Some of it is of better quality than others, but the main thing to keep in mind is that all we want is a rock that will generate a spark. It can be any hard, quartz based stone found (flint, chert, quartzite, jasper, etc.) that is harder than steel. The flint needs to be a large enough size to be gripped tightly in the fingers so as to maintain control while striking the steel. It must also have a sharp edge. The sharper the flint the more sparks result. To sharpen, you must “chip off” a small piece on the edge of the flint. Hold the steel and rock at or below waist level and strike the steel down against the portion of the flint where you want to create a sharp edge.
Steel – Not all steel works. High carbon steels, tool steels, and knife steels will work if tempered or casehardened. For the best performance the edge of the steel should be smooth. Sandstone or other abrasive rock can be used to help grind the steel. The steel piece should be large enough to be gripped and held tightly and long enough not to strike your fingers with the flint.
Char Cloth – One of the most ideal materials you can use for this method is char cloth. This material will catch a spark and glow but it will not ignite. It is used as an intermediate step between the striking and the tinder. Rather than attempting to get a spark to stay on the tinder, the char cloth will keep the spark hot until you get it to the tinder. Note: Punk Wood can also be used for this method.
There are two different methods that you can use.
Make your tinder bundle (nest) and place one or two pieces of char cloth inside the nest. Pull the nest up around the sides of the char cloth just enough to cradle it. Hold the flint and steel above the nest. Strike downward onto the face of the steel with the edge of the flint using short, choppy strokes. Keep trying, adjusting your angle until the sparks are landing in the nest. Once you see a spark catch in the char, and an area of red ember start developing in it, wrap up the char in the tinder bundle and gently blow on it until it catches flame.
Set your tinder bundle on the ground and get two pieces of char cloth. Place one piece in the bundle and keep the other piece in your hand. Place the char cloth on top of the flint near the edge so that the sparks can “spray” directly into the charred cloth. Use your thumb to hold the cloth in place on top of the flint. Hold the flint still, and strike the steel against the edge of the flint. Strike down at a shallow angle, using short, choppy strokes. Sparks should fly upward and eventually be caught by an edge of the char cloth. Once a spark lands on the char, immediately blow a light puff of air toward it. Allow the char to catch and begin to smolder. Place it into your nest and continue gently blowing until you get a flame.