Terminologywise, probably the most confusing, and misunderstood area among hikers. Campers, and survivalists, is an ancient art of producing sparks by hitting two different materials against each other.
Before the iron age, possibly the only way to produce sparks strong enough to ignite anything was to hit an iron containing rocks of iron pyrite, also known as fool’s gold, with a lot harder flint stone.
I don’t know what did the iceman Ötzi and his buddies call their magical spark tools, but definitely, it was not a flint and a striking iron. I would guess something like “Holy magical stones of fire from the Gods”.
Then came the iron age, and with it a lot stronger sparks. Iron pyrite was replaced with a piece of high carbon iron. As in the case with the iron pyrite, the flint acted as a blade, which shaved microscopic pieces of iron from the fire striker, AKA firesteel. So, the source of the sparks was the striking iron, and the tool for separating pyrophoric pieces of iron from it (which can be seen as sparks when the iron burns in contact with the oxygen of the air), was the flint stone.
For about 3000 years, terminology was pretty clear. There was the flint and the striking iron. Then, in 1903, came Carl F. Auer von Welsbach, an Austrian scientist, and messed it all up. He invented an alloy, which contained about 70% of rare earth element called Cerium, and about 30% of iron, and called it Ferrocerium. Ferrocerium was capable of producing much more intense and hot sparks than the good old striking iron. That was the point when it went all wrong with terminology.
People began to call ferrocerium a flint. That is kind of understandable, because for couple of thousand years, something able to produce sparks, when struck with a striking iron, was called the flint. However, despite the fact that striking a ferrocerium rod with a piece of iron produces an intense shower of sparks, one cannot call the ferrocerium rod a flint. It has absolutely nothing to do with flint. Flint is, as I said before, the tool that shaves pieces of iron from the striking iron. In addition to that, flint is a member of a group of very hard rocks, not a piece of man made metal alloy.
In fact, if you want to stick with the old nomenclature, you should call the ferrocerium rod a striking iron, and, whatever material you are using to hit, or scrape the ferro rod with, a flint.
You, dear reader, may ask why I bother to do this academic nitpicking of words with the good old flint?
And I must admit that I have nothing against calling any spark producing device a flint. However, the general misunderstanding of meaning of words, and history behind them, has created hordes of “experts”, who, after seeing your very nice video about starting fire with ferro rod on Youtube, immediately attack you with comments like: a) “Your video is fake, you cannot strike flint with stainless steel. It must be XX% carbon steel.”, b) “In order to get a good striking tool for ferro rod, you must heat a specific kind of metal to an exact temperature of XX degrees, and cool it down for XX time in water/oil/magical secret liquid.”, c) “If you want to start fire with a ferro rod, you must use an ancient Roman design of striking iron, or you are not using true ancient way of starting fire.”
Answers to a, b, and c are:
a) Yes, you cannot strike fire with flint and stainless steel. The flint is supposed to shave, and the metal is supposed to burn. Stainless steel and flint stone do not work. The flint is hard enough though to shave stainless steel, but the stainless steel does not contain enough carbon to make it burn in contact with oxygen. Therefore, you do not get enough tiny high carbon chips of iron to produce any sparks. However, a ferrocerium rod is soft enough to be scraped with a sharp piece of stainless steel (or any other material harder than the rod) to produce an impressive shower of sparks (remember, a ferrocerium rod is not a flint, it is a striking iron). In this case the percentage of carbon has a role in making the steel harder, and therefore, high carbon steel works better than the softer stainless steel, whereas in case of the old striking iron, the coal enabled the metal particles burn better.
b) Another case of mixing two things, which have very little to do with each other. To get sparks with a true flint stone, you need a piece of iron that is in the same time fragile enough to be shaved to tiny pieces by the flint stone, and contain enough carbon to burn well. Therefore, the treatment of iron plays a significant role in the process of producing a good set of fire starters. In case of ferrocerium rods, the only significant properties of the iron (really, the flint) are the hardness and the sharpness. The iron (or any other material) has to be harder than the ferrocerium, and sharp enough to shave tiny pieces from the ferrocerium rod.
c) If you want to start a fire using some ancient method, forget the ferrocerium rod. It was invented in 1903. Using a regular safety match stick is far more ancient than the ferrocerium rod (friction match was invented by English chemist John Walker in 1827). Ferro rod is rather new invention, and trying to scrape fire out of it with anything older than 113 years does not make it ancient, traditional, or genuine. The Greeks, Romans, or anyone living before 1903, started their fires with a true flint stone and a striking iron, and anyone claiming to use genuine ancient methods of starting a fire with a ferro rod, could as well claim that black powder firearm is a true weapon of a cave man.
Now, that the terminology should be clear; in old terms the ferro rod is the striking iron, and anything used for shaving the rod is the flint. I would suggest using the terms ferro rod, and fire scraper. Ferro rod for it’s own uniqueness, and fire scraper for the reasons that a) it does not necessarily have to contain any iron (anything harder than the ferro rod will do), and there is no need to strike anything, scraping is quite enough to produce sparks. The names I suggested would clarify the field a lot. No more sales pitches about “magnesium flints” (some ferro rods contain up to 5% of magnesium, but it does not make them magnesium rods. They still contain about 40% of Cerium, 20% of iron, and a lot of other metals.) And, we may accept that anything producing sparks can be called flint, but really, shouldn’t it be the time to name things for what they are? At least to get rid of comments like “I loved to see you strike sparks from your magnesium flint, but shouldn’t you use a higher carbon content striking iron?”
To end up with something positive, while testing different materials (flints) for their ability to strike, or in reality, scrape sparks from a ferro rod, I discovered that an abandoned dull drill bit was the best tool (flint) to get the most intense shower of sparks with almost every scrape. A drill bit is very, very hard, and it has curvy sharp edges all along it’s shaft. These properties make it almost perfect tool to strike, or, in real world, to gently scrape tiny pieces, ie. sparks, from your ferro rod. Some parts of the curvy sharp edges of the drill bit are almost always in the right angle against the ferro rod to produce a very nice shower of sparks with minimal effort. From now on, my favorite, and the only scraping tool will be an abandoned drill bit.