Flint Steel

Home > Trekking > Flint Steel

August 22nd, 2008 admin Leave a comment Go to comments

Flint Steel

what would happen if you took the flint from a flint and steel Fire Starting kit and put it over an open flame?

such as a zippo lighter?

I'm a geologist, and I work in the field all the time, having to camp out for a few days, and the flint and steel is better than anything else (except possible the magnesium strip method).

But anyway, in regard to your question... Your flint would get warm as you pumped thermal energy into it. But that's it. Flint and steel by themselves are useless. You can't start a fire with either one.

But obviously, they work together do spark and make fire.

The process revolves around a little known phenomenon of iron called pyrophorics. Pyrophorics are substances that spontaneously ignite below room temperature, which is about 70°F (21°C). By spontaneous, it means that these substances will simply catch on fire all by themselves without you having to do anything such as light it with a flame. This is also known as autoignition, if you don't want to stick with the scientifically accurate pyrophorics.

Iron is a pyrophoric material -- in the presence of oxygen, iron catches on fire all alone. It just starts burning. The curious part is that we've all (well, some of us have) held chunks of iron in our hands, and obviously, they weren't on fire.

The answer to this interesting tidbit of geology and physics is the fact that the portion of the iron in contact with the air and your skin is not pure iron. Instead, your lump of iron has built up a thin coating of iron oxide (rust), immediately upon contact with the oxygen in the air. This seal off the iron inside from exposure to the air, reduces the rate of further rusting, and stops the pyrophorics.

Rusting (oxidizing) is the exact same thing as burning, but unlike a campfire or Zippo, you'll never notice it. The heat given off during oxidation dissipates far too quickly for any noticeable heat to accumulate and be noticed.

So holding your lump of iron, you won't feel any heat as it rusts, since the heat is absorbed by its surroundings as fast as the oxidation process produces it. BUT -- if you can increase the oxidation you can cause the iron to spontaneously give off a large amount of heat very quickly, which is what we all want in order to start a fire.

To increase this oxidation, is to give a fresh, un-oxidized piece of iron more surface area in contact with the air. More oxygen touching more iron will cause more oxidation which will give off more heat in a given amount of time. That's simple chemistry.

Another method is to break off smaller particles of iron from a bigger lump. The smaller the iron particle is, the greater its surface area compared to its volume (look at some three-dimensional objects).

So following that, if you can create a small enough particle of fresh iron, then upon contact with oxygen, the high-surface area particle will oxidize -- burn -- faster than it can dissipate the heat formed during the reaction, as we're used to. The end result is that this little particle of iron spontaneously heats to the point that it actually glows during oxidation, which is quite hot enough to set fire to a proper pile of tinder. Don't try to light a six-inch log. Do the intelligent thing and take time to make tinder.

To make your *best* flint and steel...

(1) Find a piece of high carbon steel, which is about 98% iron and 2% carbon.
(2) Find a piece of flint or other hard sharp object such as quartz.
(3) Strike a sharp edge of the flint a glancing blow with the high carbon steel. Doing this just right takes practice.
(4) Very tiny particles of fresh iron fly out from the steel, begin to burn, and if you do it right, light your fire.

There are all sorts of technologically-enhance flint-and-steel that supposedly work better. But your regular set is cheap, and it's never failed me. But - that's what happens if you just try to set fire to a piece of flint.