Sven Ruppert

Today we’re going to look at how to make a rocket stove with an axe and a saw.
The construction does not require any other materials such as wire or the like.
This is a variant that can be used to boil water yourself.
Even in wet weather, this variant works very well because, with the correct selection of the workpiece, the inner dry wood is used to generate sufficient embers.
In this construction, the physical effect is used, in which hot air rises faster than the colder ambient air. This is, among other things, the reason why this variant works better the colder the ambient temperature is.

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Search / select wood

The first step is to choose a suitable piece of wood. There are a few things to consider here.
Only one tree that has already died should be used for this work. There are several reasons for this.
On the one hand, the principle “Leave no trace” applies to me. So, avoid all traces as much as possible.
Therefore, damaging or even cutting down trees that are still alive is an absolute NO-GO for me.
But there are also purely practical reasons to concentrate mainly on deadwood when searching.
Most woods are much better to use as fuel than fresh and, therefore, still damp wood.
Exceptions here are woods with a very high proportion of resin. Many conifers are part of it, but birch is also an excellent raw material for a fire. Birch burns very well, even when it is wet. This is also one of the reasons why birch bark is very popular as a tinder material.

(But I’ll show that in more detail in another video)

However, there is one more thing to keep in mind. If you want to use this rocket stove for cooking, you should avoid wood that is too resinous. During the incineration, many particles then settle on the cookware, which then has to be removed with incredible difficulty. So think a little about the work that follows.

Wood that lies on the floor is usually more humid, possibly even slightly rotten. These woods can no longer be used and have a poor calorific value, and are usually the basis of many insects’ lives.
It is best if the part of the tree trunk is suspended in the air, i.e. not touching the ground. If you knock on wood, you can already tell from the sound how much moisture is still to be expected in the wood or how strong the decomposition process has already progressed. A bright sound is usually auspicious.

Let’s come to the size that is well suited for this project.
I prefer woods that are no more than the length of the palm of my hand.
There are several reasons for this. Firstly, these are easier to edit in the following work steps.
Second, these sizes can still be easily edited with handy tools. For thicker workpieces, you usually have to provide makeshift tools.
(How to split very thick tree trunks with a small axe, which I will describe in detail in another video.)

Saw off wood

It has been shown to me that I prefer to use pieces between 30-50 cm long in terms of length.
They have the advantage that they are stable in the fire for a long time, can be quickly processed and do not burn too long. The burning time is sufficient for preparing a meal for up to two people, followed by coffee and warm up a little while the coffee is still being enjoyed. The burning time, however, is heavily dependent on the type of wood used and its quality. For sawing myself, I use a saw on tours that has a relatively long blade. Indeed, shorter saw blades can also be used, but I prefer to carry a few grams more with me and then have more comfort when working on the wood.

Split / split wood

As soon as the workpiece has been found and sawed out, you can start splitting.
An old tree stump that can be used as a base is suitable for this.
This has the advantage that the work can also be carried out quite quietly.
Who would want to reveal their position to all hunters and foresters with loud noises?
Stones are only conditionally suitable as a base. Here you have to reckon that the axe hits the stony surface while working with the blade and thus quickly loses its sharpness.

The piece of wood must now be split lengthways into three or four equal parts, if possible.
The trunk must be divided along its entire length.
It is also crucial that the parts are as thick as possible so that all aspects burn at the same speed later during usage.

Remove insides

Now that we have three or four pieces, the chimney can be carved out. This is done on the inside edge, lifted some chips. The result is a free space in the middle. This achieved that an internal tube is created that can be used as a stove pipe. Ultimately, the point is to enable the hot air to rise in a targeted manner. This makes a draft that will constantly draw in fresh air from below. The chimney effect has already been achieved. When all parts are put back together, you can look through the length of the workpiece once.
The work itself does not have to be carried out too carefully. Likewise, not too much material should be removed, as it will only shorten the burning time. A reasonably small opening is enough for a good draft. I use my thumb as a measure of the diameter.

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Cut the combustion chamber

There are now different ways to operate the Rocket Stove. I mostly cut a small combustion chamber into the bottom. For this purpose, a notch is engraved on the underside of a side part.
For this, you can do the rough preparatory work with the saw by cutting a triangle. Then the opening is worked out a little more with the axe. But you can do that at will.
It should just be such that the opening is enough to add fuel. This facilitates lighting during the first few minutes to light a sufficiently large flame.

assembling and installation

A relatively straight base is required to operate the furnace. There the parts are placed next to each other.
Most of the solutions I see with others use a piece of wire to hold the pieces together.
First of all, you must first have carried such a wire with you and, secondly, the wire must not have been left behind at the place later.

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Attach side supports

I use material from the surrounding area to support the parts. A few small branches that are anchored in the ground to hold the side parts are sufficient. And you are done with the construction and can start operating. As it burns down, the small sticks are simply moved along the sides of the fire.
You could also sharpen the underside of the individual parts. This means that you can even anchor the stove on the floor. This even saves you the side supports.
So, leave the wire at home and use a couple of small sticks.

Collect birch bark

Birch bark is ideal as a tinder material. Usually, there are individual birch trees in many places in the forests, a pioneer plant. Some birches have some areas where the bark has already peeled off. It is better to use dead birch trees. You can then peel off the bark from these trees with a knife or axe. The birch wood can also be used as it contains quite a lot of essential oils, which enables it to ignite when it is moist.

Prepare the tinder

Now we come to the operation of the Rocket Stove. For this, we need tinder to get the flame so big that we can light the wood with it. For this, you can use the bark of the birch to light a flame with a few sparks from a fire steel. Chop up the birch bark a little and place it on top of additional tinder material. Old bark is suitable as a base to get the glowing nest into the combustion chamber. If you have fat wood, you can, of course, also use it.

Kindle

As soon as you have lit the fire on the bark underneath, you can use a stick to push the embers into the combustion chamber. The chimney effect should set in immediately and ensure a reasonably constant flow of fresh air. After a short time, the fire begins to rise along the chimney pipe. The resulting heat flows out of the opening and can be used immediately to heat food or water.
However, it is not advisable to place the mug directly on the chimney opening, as this interrupts airflow. Much smoke will usually be the result; two small sticks under the cup will solve the problem.

Conclusion

We are now able to manufacture a rocket stove ourselves with minimal effort. This gives you a controlled fireplace that is well suited to heating food and water in damp weather. It is also recommended to use it as a heat source near a warehouse. The wood consumption is meagre with good heat yield at the same time.

To extinguish the flame, you can pull the individual parts of the Rocket-Stove apart and press the embers on the floor. The flight of sparks is easy to control with this type of fireplace. In an emergency, the fire can be annihilated quickly with a bit of water if allowed to run directly into the chimney opening. The embers are, of course, not yet extinguished.