Lighting a fire with a ferro rod

A ferro rod is made of ferrocerium, a metal mixture consisting mainly of the element cerium and other so-called rare earths, plus iron. When you scrape it with a hard, sharp edge, tiny metal particles come off. The heat of friction makes them ignite in air and burn as glowing sparks. The same material is used as the small flint in many lighters.

Each spark is very hot but tiny and gone in an instant. So it delivers its heat only at one point and only very briefly. That is why a ferro rod needs tinder with a very large surface and little mass: cotton wool, shredded birch bark, the finest shavings. In coarse or damp material the sparks simply fizzle out.

Ferro rods are often called “magnesium rods”. That is not correct: magnesium is a different metal. There are, however, combinations where you scrape fine shavings off a magnesium block and ignite them with the ferro rod. Magnesium shavings burn very hot and can help difficult tinder; but scraping them takes a while.

The tinder decides. Build a loose, fist-sized tinder bed on a dry base, for example a piece of bark, and tease it out so finely that lots of fibres stick out. Kindling in several sizes lies within reach, because a burning cotton ball does not last long.

The technique is simpler than it looks: put the tip of the rod directly in or just above the tinder. Press the striker firmly against the rod at a steep angle, hold it still and pull the rod firmly back. That way the sparks land right in the tinder, and you do not knock the tinder pile apart with a forward stroke.

The striker needs a hard, sharp, right-angled edge. A suitable striker is usually supplied. A knife spine only works if it has a sharp edge; many knife spines are rounded. New rods often have a black protective coating that you must scrape off once in one spot before sparks appear.

The ferro rod is an excellent backup in an emergency kit: it hardly wears, is insensitive to water, and cold does not bother it, unlike the gas in a lighter. How many strikes a rod gives depends on its size and your handling, but there are usually a great many.

Its weaknesses: it gives no flame, only sparks, so it needs especially fine, dry tinder and some practice. With very cold, stiff fingers the firm pull is hard. Without suitable tinder it is practically useless.

So a ferro rod is not a replacement for matches or a lighter but an addition. A good combination is a lighter for everyday use, a ferro rod as a robust reserve, and carried tinder in a waterproof bag.

The sparks fly further than many people expect and are very hot. Use the ferro rod only at a safe fire site, not near gas canisters or fuel containers, and never aim sparks at people. Protect your eyes and clothing; synthetic fabrics can get holes from sparks.

If you use a knife as the striker, use only the spine and keep the blade pointing away from your body and the tinder. Many injuries happen because the edge slips during a firm pull.

As with any fire: check the local rules and the wildfire danger beforehand. A fire ban applies to practice fires too.

First practise just making sparks, without a fire, for example over a fireproof base in a place where that is allowed. Try different angles and pressure until each stroke gives a strong shower of sparks. Then practise with cotton wool, and after that with natural tinder such as shredded birch bark or fine shavings.

Be aware that natural tinder is much harder to ignite than cotton wool. Anyone who has practised this at home and in good weather is more relaxed in the field. Anyone using a ferro rod for the first time in an emergency often fails because of small things like the protective coating or tinder that is too coarse.