DIY fire torch

A simple DIY fire torch is described. It can be used as a controlled source of ignition when burning-off unwanted farm vegetation at multiple locations.

Background to the DIY fire torch

Traditionally, I have used a tight roll of newspaper as a torch to ignite burn-offs on my farm. While effective, such a torch will quickly catch fire along its whole length. This means that it becomes unusable for starting burn-offs of multiple windrows of vegetation and Serrated Tussocks.

For the pyromaniacs amongst you, here are a couple of little videos of the rapid spread of the fire from the fire torch with the aid of a little diesel spray. They show its use on a weed windrow and a Serrated Tussocks.

This is a short post about a simple DIY tube device that turns a roll of paper into a torch that produces a persistent and safe flame that is well away from my fingers. This means that a single cheap torch can be used to ignite a fire stack in many places to take advantage of prevailing winds or start multiple small burn-offs over an extended period.

Making the DIY fire torch tube

A piece of metal tube such as a portion of a metal vacuum cleaner stem would suffice. However, pandering to my passion for tinkering, I made a custom tube from ultralight stainless steel foil by welding the seam after rolling the foil into a tube.

Optimising the newspaper fuel rolls

Endless optimisation. “I am still optimistically optimising the making of these rolls to be simple to make and install and yet provide a persistent and instant source of ignition during field use, so I expect to make changes as my experience grows”

I have found that it is much easier to make the newspaper roll inside on a flat surface and out of the wind and other distractions. The rolls should be neat so that they easily slip into the tube. Then they should have enough friction to prevent them from falling out.

Tight newspaper rolls. I have been tempted to make the fuel roll very dense so that it burns slowly, lasts for a long time and provides the required friction. “Yes, they last so long because they do not burn so freely!” Also, I have been tempted to make the rolls very long so they will last longer and the protruding paper at the back end provides for adjustment of the burn tip length. However, from experience a very dense and long roll does not burn so well and the protruding spare paper gets damaged and damp during field use.

The dense roll has a burn characteristic that smoulders rather than naturally holding a persistent flame. It burns to a hard bee hive shape that usually requires more diesel and an ignition source to start a flame quickly. “Its density makes its performance equivalent to a dry stick with a ‘sniff of diesel’ on it”.

[Add a photo of the bee hive finish showing the less than ideal burn zone]

Looser newspaper rolls. On the other hand, if the number of sheets is halved and their length is similar to the fire tube body, the paper rolls can be easily fitted into and protected by the fire tube. A stick can be used to adjust the fire tip in or out. The friction fit is still good as the roll expands within the tube and a hollow or tunnel forms down the length of the roll.

In contrast to the tight roll the less tightly packed paper burns more freely and persistently. I think this is because the combustion/smouldering is maintained in the hollow inside the paper roll at the end of the fire tube. It concentrates the heat within the smouldering embers and protects them from excessive cooling by the wind as I think happens with the bee hive burn.

This hollow burn function means that the paper fuel is consumed a little quicker while actively flaming, but it is still delightfully slow during the smouldering phase when the torch is in standby mode. The burn will slowly collapse to a slow and persistent smouldering phase inside the hollow tip if traces of diesel are not added.

Instant flame re-ignition. The persistent smouldering of the loose paper roll can instantly be re-ignited into flames by simply blowing into the glowing hollow (or pointing it into the wind). Fiddling with a gas lighter or a squirt of diesel is no longer required for re-ignition to an active flame, as with the dense fuel roll. The magic of the hollow burn flame recovery can be seen in this little video.

With this hollow roll configuration, the torch must always be kept pointing somewhat upwards, and away from the wind to prevent unintended reverse burning caused by the tunnel acting as a chimney or exhaust pipe. “Luckily, my hill farm has no shortage of slopes that point vaguely toward heaven. They provide plentiful safe resting places for the smouldering torch that also point away from the prevailing winds that make such burn-offs satisfyingly effective .”

Safety note: Lastly, the persistent and sneaky smouldering combustion of the loose and hollow fire torch is delightful. However, it could provide an unwanted fire risk when it has finished its active duty. Dunking the tip in water will render the torch safe but inoperable for some time.

A more effective and constructive quenching of the combustion can be perversely arranged by careful spraying of the smouldering paper embers with excess diesel until no trace of smoke can be detected. This leaves the fire torch primed ready to be instantly used again. Even so, storing the ‘extinguished’ fire torch in a safe non-combustible place would be a prudent precaution as some residual embers may remain hidden among the many leaves of rolled paper inside the torch.

How many sheets are in the newspaper coil? My fire tube has a 37mm ID. To make a loose and hollow paper fuel roll described above, I use 10 sheets of newspaper. I fold them in half and then from the side with the loose leaves I roll up the 20 layers very tightly with the spine of the paper folds finishing on the outside of the roll. This folded spine can be easily held down with a single temporary sticky tap tab to hold the roll in compression. Then, when it is partially slipped into the fire tube, the tab can be released to allow the roll to expand into the fire tube to attain that ideal friction fit and the magic hole or tunnel down the middle.

The alternative rolling of the paper with exposed leaves on the outside makes the roll harder to manage and fit into the fire tube and the loose leaves in the burn zone can spring out and burn away too quickly from the outside of the tip.

Using the torch

This DIY fire torch is delightfully light to carry between ignition points and it keeps my hands safely away from the flame. To get the best result, I squirt a tiny amount of diesel or kerosene onto the protruding paper wick to initially set it alight. The burning tip can be pushed in or out to regulate the flame size.

Now it is some time since I have included an ode, so here is one for fellow pyromaniacs:

The young man used burning paper his farm weeds to scorch,
The uncontrlled flame often made his fingers say ouch!
Now old, the paper is held in a long pipe,
After so many years the idea is surley ripe,
And so the same newspaper becomes a fire torch.   

Tim