Today in the Fire Lab we’ll be learning about flint, chert and ‘firesteels’.

In our test today, we’ll be using our standard firesteels, and the brand new all-metal firesteel based on my ‘lightsaber’ design, now for sale in our store in a brand new limited edition gold tin.

The standard firesteel ‘striker’ set comes with a steel blade for scraping the ferrocerium rod, but I do recommend trying flint as an alternative. It’s all over the place in Southern England, and if we zoom in on the gravel here in my back yard, you will see 1 2 3 4 56 flint all over the place. Flint of this size can be found just about anywhere from the Midlands down, just lying around in driveways and laybys disguised as gravel.

We’ll also be testing the main prototype for our new all-metal firesteel and using larger pieces of flint and chert in this stress-testing process.

Flint is gray to black and nearly opaque (it’s translucent brown in thin splinters) and this is because of carbonaceous matter in the stone. Opaque, dull, whitish to pale-brown or gray specimens are simply called chert; the light colour and opacity are caused by abundant, extremely minute inclusions of water or air that also weaken the structure.

So here’s two common strokes showing a steel blade being used on a standard ferrocerium rod. Note that you can choose to move the blade, or the rod, to get the same effect.
Small bits of flint or chert work the same if not better on both strokes, but you will see that a larger stone is more useful for a stroke where you hold the stone, and move the rod.

Moving on to the main stress test, here’s a standard firesteel finding sharp edges on flint, and here is our all-metal firesteel exploring the same stone, looking for sharp edges while we also stress-test the handle on blunter edges to ensure the new design does not wiggle loose over time.

Here for reference is a piece of carbon steel, shaped into a small file, that we’ll be using to show what you might expect from an actual ‘flint and steel’ combination. Put simply, it’s a lot of work for a little biscuit.

Here’s a rusty old Allen key also made of cheap steel, and you can see it requires more pressure and effort to elicit the occasional spark. This rusty old nail requires even more pressure and effort to produce the same modest result, and it is here that we’ll discover where chert is different.

No issues with the standard striker: sharp edges mean lots of sparks, AND because chert fractures more randomly than flint, you usually end up with more notches, which allows you to scrape your firesteel with two edges instead of one, resulting in more sparks and therefore better chances of landing one right where it counts.

BUT once we switch to old-fashioned carbon steel, you will note that we’re still only getting modest results, AND blunting the edges with every stroke. In fact, by the time we move on to the rusty old Allen key, you will note some pieces breaking off, and that using the pressure necessary to elicit sparks from the rusty old nail has a catastrophic effect on the edges of the brittle stone.

So the difference is that flint is a purer form of chert and chert is subsequently more brittle than flint, but that really only matters if you are trying to get sparks from hard steel.
Our new all-metal firesteel is available for sale in store in a limited edition gold tin with genuine flint and chert pieces for striking, along with our standard firelighter kits in red, green, blue or silver.

Our store also has some of the prettiest firelighters ever made, if you have a fireplace at home and want to class up the joint.

Thanks for joining me in my enthusiasm for fire. Cheers all.