Ultralight Blower Stove Article, Story of the Development.

This is my story of the development of an ultralight blower stove to provide controlled heat for cooking outside. They use long damp fuel sticks that I so often encounter while walking and skiing in alpine areas in both summer and winter.

Caution: If this long story might put you to sleep you may wish to skip to my Blower Stove Gallery Index to find the right stove for you from the big range of stoves. Alternatively, you may wish to skip to the KISS stove that can combine a blower, alcohol, and tent stoves, all in one tiny ultralight backpacking bundle. This should keep you awake.

Introduction

I wanted a stove that would:

• Have a short startup time and rapid cool down time,
• Have a quick recovery time after a substantial idle period,
• Boil water quickly for copious hot drinks and cooking for a single person or a group,
• Pack up inside a cooking pot so that, with care, it could be safely be carried in a backpack
• Burn well with damp or wet sticks, and
• When using bush sticks as fuel, there should be minimal fuel preparation and simple fuel feeding that is not a chore

Background to My Ultralight Blower Stove Development Journey

I have always been fascinated by the amount of free renewable heat energy that can be released from a hand full of fallen bush sticks and the joy that they provide when they are burned to provide unlimited hot drinks, comfort, and hot meals for walkers or skiers where they travel. My challenge was how to manage the combustion process so that I was its master and not its slave.

My interest in little wood-fired ultralight blower stoves was kindled during a car-based extended family camping trip/tour in Western Australia where wood for fuel is often a scarce resource. My innovative Nephew, Rob had made a DIY stainless steel fire pot for cooking. It was about the size of a 2-gallon bucket. It made efficient use of roadside sticks for smoke-free cooking and still provided warmth for comfort on a cold night. The stove also became a focal point for human interactions and for my Grand Nieces, there was scope to toast things and play with fire.

I also have an ‘Easy Boil Billy Teapot’ made by Cecil & Co. P/L ( I call it a ‘bush kettle’) I have used it for car-based trips and it is wonderfully efficient for boiling water (far more efficient than the stoves that I have developed), particularly for a group on long road trips where breaks for a ‘cuppa’ are good for safety and enjoyment of the journey. However, it is just too bulky, heavy for backpacking, and it is not suitable for direct food cooking.

All this inspired me to make a miniature lightweight version of a fire pot for lightweight backpacking camping. I thought that I had lost contact with any examples of my early stoves (as they were rapidly replaced by improved designs), but as luck would have it, I found an old stove stashed away in my yacht during a recent tidy-up session.

At this stage, I was unaware of what other walkers were doing with wood-fired stoves. Recently Rob Jung (another Rob) shared with me his designs and detailed investigations into natural draft stoves that burn bush sticks. twig stove article. He has thoroughly investigated the critical factors for success in making small stick stoves in his informative article.

To my shame, I did not do such research. Most of my early stoves were made by ’trial and error’ with big food cans for the stove body with air vents at the bottom, removable pot stand legs at the top and I called them ‘ring-stoves’ and according to Rob’s stove category table they would have been called ‘chamber pot stoves’. The name is not all that complementary and it gets worse, Rob tested them and he assessed them as the least effective category in the stick stove range with regard to water boiling rate and tolerance of wind.

When walking or ski touring, for me this type of stove did not meet my expectations particularly when fueled with damp bush sticks on cold Gippsland evenings when multiple hot drinks and hot food are always in high demand for re-hydration and recovery from a hard but enjoyable day of travel. So I was off to find or make a better wood stove that responded more like a gas stove.

Out of curiosity, I have just made a test stove according to Rob’s design principles. I did this by cutting off an 80 mm long portion of a large ‘baby formula tin’ which was the same diameter as my large blower stove and simply added it to the pot stand of the blower stove(~60 mm high) giving a total height of 150 mm. I put in a perforated hearth grate 20 mm from the ground, according to Rob’s design rules. On a windy evening, it boiled 750 g of water (in a big beetroot tin) in 8 min (without the blower operating) and refinement could make it much better.

My journey may have taken a different road if, I had known then, what know now about these little natural draft stoves.

Luckily, I have found throughout my life that, ignorance of the ‘proper’ way to do something can be a powerful driver of innovation. It simply prevents rat-tracking of thought processes. So I possibly have stodgy damp Gippsland sticks, abundant ignorance, and the gift of a broken down Toshiba laptop to thank for the unique stove journey that I have taken.

Me

A fork in the road of ultralight stove development

My journey split into two related paths, one of which is described in the current article about ultralight blower stoves for camp cooking in the outdoors using dead sticks as fuel. The other path led to the development a very simple, no-fuss small round KISS tent stove that is light and easy to carry within its own cooking pot.

Back to ultralight blower stove for cooking outside

I purchased a ‘WoodGas Campstove’ (woodgascampstove.com) that is an inverted fan-forced (batch) wood gasifier stove. It was a lovely little stove, designed as a (batch) inverted gasifier burner that is lit from the top and the fuel sticks burn downwards.

However, it cracked in four places around the stove casing after a little use. (See one such crack in the photo below at the bottom of the stove passing through the second vent hole from the stove centre.). It would quickly run out of little fuel sticks before the cooking was completed. Refueling with more sticks from the top was inconvenient as the cooking was interrupted and the pot stand ‘cross’ impeded stick addition

Importantly, after the fuel addition, the burn was ineffective (not surprising given that is designed for the batch of fuel sticks to burn from the top downwards).  If refueled from the top it would turn into a powerful smoke generator when extra fuel was added and normally there would be no flame unless the smoke was ignited by me. It possibly could be good for bee smoking, or smoking eels, but not for cooking substantial meals or boiling substantial pots of water.

Also because fuel sticks needed to be so small and uniform for the burner to work well, it was tedious to make fuel in the bush (my early bottom-upwards-burning stoves shared this fault to a less critical extent).

The stove was quite heavy (650g) for backpacking and I did not like the design feature that housed the fan so close to the high-temperature heat source and depended upon a stream of cool incoming air to prevent its damage. The fan could easily stop during a strong burn when battery powerfailed!

Despite this stove’s disappointing performance, the hot clean flame that it produced, some of the time, impressed me in that it was possible that in a small burner with forced air supply, wood could be made to burn well, just like a gas flame.

Another clean-burning stove

My tent stove (described above) achieves this type of burn while making a gentle cat purring sound (without a fan), largely due to the draft effect of a long flue pipe that towers up through the top of my tent canopy.

An alternative strong airflow can be also be produced in a rocket mass heater stove with a relatively short, wide refractory, insulated heat riser but the weight and size of such a stove is not suitable for backpacking, so I would need to create my draft by a lightweight method.

Both the above stoves showed me that clean combustion of my crappy wet Gippsland wood sticks is possible. However, I needed to find an effective, light, and compact way of better providing that strong stove draft.

My first steps with  stick burning ultralight blower stoves

To address the issue of slow-burning with wet wood, I decided to add a remote (unfortunately not quite remote enough) 5-volt laptop fan to my traditional ring stove to increase airflow.

“Now just in case, you think that I rushed straight to find a good and immediate solution, have a look at the next photo of just some of my failures. I prefer to think of them rather as lessons for a slow learner.”

Me

In my first blower stoves, in my ignorance, the blower was arranged with the largest possible air delivery tube (~30mm diameter) aperture to reduce pipe friction and maximize airflow through the stove as in the Wood Gas Campstove described above.

However, I speculated that the velocity of the forced air jet (rather than the volumetric flow rate of air per se) would be more important because of the turbulence it produced when striking and attacking the charcoal. The intense heat would make more wood gas and the air turbulence created would cause improved hot clean combustion of the gas.

My hunch was born out by my own experimentation and others who place great importance on air turbulence in rocket mass heaters, just beyond the wood pyrolysis zone, in their stove designs, in order to achieve efficient clean burning of wood gas.

It is also important to note that the blower does not deliver enough air (nor does it need to in my current designs) to cause complete or stoichiometric combustion of all the wood gas (in other words, ‘no smoke combustion’).

A secondary source of air can complete the combustion as the flame exits the burner at a high enough temperature and with any small flame as an ignition source. This means that little or no smoke escapes the combustion process.

This secondary combustion can occur underneath a second cooking pot for a blower stove (or in the labyrinth heat exchanger box in my tent stoves). I have progressively reduced the primary air input aperture to improve the power of the blower stoves to produce stronger and cleaner burning.

I also found that this high primary air velocity improves the rate of utilization of the charcoal (produced by the gasification of wood) and helps to achieve a good balance between the ratio of charcoal to pyrolyzing wood in the burn chamber (See  Wood and Charcoal Combustion for more detail ).

Some comforting words. Don’t worry if all this sounds a bit complex as it has taken me years to understand what I am actually doing! I have only just clarified the process in my mind by writing this article. Put simply; the blower is the source of high speed ‘primary air’ that attacks and burns charcoal to produce very high local temperatures (~1,600C) and heat, in the burn chamber. This heat, in turn, pyrolyzes the wood to make abundant fuel gas that burns gently with a secondary source of air that is mixed by the jet of air.

Me

I did not at first approach my blower stove design as an inverted batch burner (burns from top-down) as the  ‘WoodGas Campstove’ does (with the first fuel load), but I made it a ‘bottom-up’ burner so that it would avoid the refueling and ‘flame out’ problems encountered with the above ‘WoodGas Campstove’, even if it was less efficient.

My design meant that fuel could simply be continuously added above the hot coals to replenish the flame and make more coals. My design strategy was to make the stove have neglegible draft when idle so that it would ‘hold- fire’ in the hot coals for a long time. This is unlike Rob’s stick stove above that continuously draws air through a grate.

A long idle time allows the cook to eat a course of a meal without hurrying and enables the quick re-establishment of a good blaze with little effort to start cooking again. Simmering the next meal course or water heating can still happen during this ‘idle’ state. I knew that this approach would reduce stove efficiency and make a much bigger flame than I needed. However, to me, cooking convenience is worth more than efficiency when lightweight camping and the fuel used is free and so little that efficiency is of no concern.

As the story unfolds you will see that my blower stove eventually morphs more into a horizontal ‘end burner’ which goes a long way to achieving efficient clean burning which is a goal of all high-efficiency wood stoves. The best of these stoves completely burn a small portion of the loaded fuel at very high temperatures at any given time. Almost complete combustion of the charcoal is required before more fuel can move into the burn zone. This makes a very stable, efficient and clean burn. Wood pellet stoves can do this to perfection as wood pellets just trickle down into a white-hot combustion crucible as they are used up and residual ash is blown away. How Pellet Stoves Work

“That’s enough, theory let’s see what happened.”

A blaze of success with an ultralight blower stove

Despite collapsing pot stands and melting of stove fans, my first test of this crude prototype blower stove was a stunning success. It could even easily burn wet wood in the rain.

“I knew that there would be no going back to natural draft stoves, except out of necessity, I had unleashed a fire breathing dragon”.

Me

The good stuff

The flame was clean and big (possibly toooo big). Heat output was massive, boiling time was fast and once started it would just devour damp, wet, and even frozen wood.

The bad stuff

So much heat was generated that the blower fan and the battery case started to melt.

Fixing the stuff-ups

The melting was simply solved by increasing the distance of the battery and fan from the radiant heat of the burner. I made the connecting manifold longer and out of less conductive stainless steel, instead of aluminium.

Most great advances usually come with new challenges. These challenges are sent to make us humble. They teach us that knowing something new is simply making a higher platform that extends the horizon of our knowledge of what we still don’t know.

Mothy, the mother of necessity.

In my case, this ultralight blower stove burned the tiny amount of fuel at a high rate and, much of the heat was wasted as flames that shot out around the bottom of the pot. The quantity of fuel per se was not the problem so much as the tedious job of cutting up such short fuel sticks to fit them into the ring of the stove and also constantly having to lift the cooking pot to do so. “Never fear, the fix was in plain sight!”

Despite these limitations, this was very a sweet stove for my ultralight extended overnight trips. I used various incarnations of this blower stove for some years. It was fun to cook with and could be used with a big dinner pot. It could rapidly make ‘tea for two’ or boil plenty of water for multiple coffees cocoas, soups, and water serialization for a group of people when the trekking was over and rehydration and recovery was needed.

Gentle cooking of meals was achievable but required close attention to prevent food from burning onto the pot. Simmering on the charcoal bed, without the blower on, was one simple solution. Dodging the escaping flames while cooking and stirring food was another challenge.

On Backpacking trips, mysteriously, little piles of suitable broken sticks would appear by my stove (in exchange for boiling water) and we seldom left a campsite without leaving a little pile of sticks for next time.

Me

Even when a good campfire was available (and allowable) for comfort on cold nights, this little ring ultralight blower stove was used beside the campfire in preference to cooking on the fire. It was more controlled, stable, and convenient. It avoided those campfire spills and the burning of food onto pots. Also, scraps of charcoal and burnt stick ends from the campfire provided an endless and effortless source of fuel for the stove.

I attempted to control the blower stove’s big flames and harness the wasted heat energy for a second cooking position. I put various exhaust port holes on the stove body to provide direction to the exhaust stream.

These strategies worked periodically and a lovely ‘rocket flame’ would shoot out of the side of the stove. Sooner rather than later the flame would extinguish and be replaced with a dense plume of smoke. This could be re-lit with a cigarette lighter flame. However, as soon as there was a puff of wind or a cold pot of water was put in this secondary flame for heating, it would extinguish the flame.

An improving ultralight blower stove

Bigger burners

I found that a large diameter ring-stove that could be carried inside my largest cooking pot was more efficient than a smaller stove. This was because the fuel sticks needed less breaking. Also, it is easier to break sticks that are longer. It also meant the heated surface area of the pot was greater and improved heat absorption. I also found that a low-profile firepot was more stable and needed less fuel for water boiling if the base of the cooking pot could be close to the very hot wood coals (est ~1,000 C).

Ring burners with tongue and groove joints  

With regard to ring-burner diameter, I also discovered that I could make the large stove more compact for carrying by having a ‘tongue and groove’ joint down a split in the side of the ring-burner. It could be tightly closed together while in use and also be opened up to allow it to be rolled up (or out) to make it fit within (or outside) a pot or another backpacking item. I found that the tongue & groove Joint could be held together tightly by fitting a retaining band made from a thin ribbon of stainless steel. This strategy restored the strength of the ring-stove for supporting heavy pots that could be more than fifty times the weight of the stove.

I used variants of this ring ultralight blower stove for some years. They burned well (even if somewhat inefficiently), and could cope with wet wood. They boiled water quickly and cooked food without the need to carry fuel, but they had some deficiencies such as;

• Fuel sticks needed to be cut to less than the diameter of the fire pot,
• Usually using a tool of some sort was needed to cut thicker sticks that were needed for sustained burning,
• The cooking pot needed to be removed to add thicker fuel sticks,
• Overheating on the bottom and up the sides of the pot resulted in food being burnt-on,
• Pot handles got too hot and insulation would burn and
• The cook’s hands were not protected from the flames when the cooking pot was being stirred.

Ironically, at this stage of development, I did not realize how close I was to my ultimate blower stove design as described later. That is a tinkerers lot! Have you worked it out yet?

Me

The student blower stove

The student stove is made from a tuna tin and was designed to be simple and cheap for students with small budgets. I thought it would:

• Allow thicker short fuel sticks to be loaded without requiring me to remove the pot,
• provide two fuelling ports,
• Integrate the pot stand with stove body so that it could never be left behind,
• Improve stability and
• Provide two slim flame protection zones for the cook’s hands.

A fortunate mistake

One evening I was using my student stove to help with the cooking for a substantial group of people from my walking club after an evening walk in a local National Park. “Don’t bring thermoses I said I can make loads of hot water for everyone on my ‘turbo stove’.”

That night, I had misplaced my trusty secateurs that I use to cut the little sticks to the required length to fit inside the small circular blower stove. Luckily, this prototype ring-stove had two deep cut-out dips opposing one another in the wall of the burner ring.

So, to save face, with the encouragement of my friend Geoff,  I experimented by poking long sticks (broken over our knees) through both the dips. Soon enough the sticks burned in half. Then we burned the halves into quarters and so on. This saved the day (or evening) and it was very effective and easy and so it immediately seeded fresh ideas on a long-standing challenge of inconvenient fueling of my Ring Stoves.

The next day I took a Ring Stove with a split side (as described above) and opened up the split to make the burner ring a C-shape (’C-Ring’) that was about the size of an old favorite cooking pot. This arrangement left a generous fueling opening that was about 50 mm wide and 70mm high. It provided space for loading about 3-4 long fuel sticks of up to 25mm diameter. The opening also provided an exhaust port and secondary air mixing zone for the hot and incompletely combusted gasses. “It all magically combined to make a hot and stable tongue of flame flow out from the fueling port. And, yes it could easily dry the damp incoming fuel sticks”

Immediately I lit it up, I knew I had a winner with a strong tongue of persistent flame passing out from the core of the burner, through and over the incoming fuel sticks providing strong drying of wet fuel sticks. The tongue of flame occasionally curled around close to the blower fan and batteries with wind, gusts, but importantly, it did not go out and there was hardly a trace of smoke.

With a pot covering the C-Ring stove the combustion chamber is essentially closed and the flame is tamed so that it is no trouble and could be put to another use or uses. The combustion is even stronger and cleaner with the pot in place.

Prototype C-Ring Ultralight Blower Stove

To make the C-Ring stove body more stable I formed welded edge tubes in the sheet metal of the stove body, along the sides of the C-opening. I then used bent hard fencing wire to bridge the gap in the C-shape by threading the vertical legs of the bridge unit down through the edge tubes.

The horizontal portion of the bridge wire was bent outwards with a shallow D-shape so that it cleared the wall of the primary cooking pot. The D-shape would eventually evolve into a deep V-shape to act as a second pot support. This completed the ring structure and made it strong again. Initially, I allowed the wire legs to protrude below the stove to act as ground spikes to give the stove lateral stability when pushing fuel sticks into the stove. However, this design was impractical for use on hard ground and the size of the wire made it less practical to carry in a compact backpacking load.

Taming the dragon flame and harnessing the heat from the C- ring blower stove

The sweet success of the prototype C-Ring Stove spurred me on to make an improved stove that would be;

• Strong, light, and durable,
• Better control the flame,
• Heat a second pot and
• Rollup for compact packing.

Rollup stove body

The titanium foil C-Ring Stove body forms a high-temperature burn chamber that is enclosed on top by the primary cooking pot and on the bottom by the ground beneath the stove. The pot should have a snug fit inside the ring wall or a flat fit on top of the wall. The seal with the ground can be made by pressing the edge of the wall into the soil and/or by spreading soil or ash around the inside and outside of the perimeter of the wall. The stove body also has a titanium ground peg that can be used to stabilize the stove against gentle pushing forces from feeding fuel sticks into the burner.

My fiddle free blower stoves that have a combustion chamber formed in a bowl with a bottom obviate this latter requirement, but the stove bottom should be liberally coated with ash (~5mm deep to provide insulation for the stove bottom and more heat for cooking. If required the stoves with bottoms can also be used for ‘leave no trace’ cooking if set up on rocks or a suitable metal plate or pan with ash or soil as an insulator inside and out.

Stove body bridge wire

As in the prototype stove, the burner ring opening is stabilized by a hard titanium bridge wire. A large ‘V’ is formed in the horizontal section of the bridge to form a support for a second pot.

Easy blower stove fuelling

The fueling could not be easier. The long fuel sticks just needed to be pushed gently into the burner as the hot ends collapsed into glowing coals. The hissing steam and boiling sap from the other ends of the wet fuel sticks was a delight but a safety issue that would need to be managed. This was much better than any of my previous stoves. So was the recovery of a good burn after an idle period of 30 min or more. It was just so easy to push the hot dried stick ends into the burner, add a Waxie Fire Starter and turn the fan on and there was no need for secateurs or fuel preparation tools.

Victory over wet fuel sticks with blowers

I could see that wet Gippsland fuel sticks had met their match. The radiant heat and the flame from the exhaust port could dry the wettest sticks before it was their time to be pyrolyzed. “………keep pushing sticks in for the strongest burn for water boiling or ease off for a weaker burn for simmering…….remove the blower for an idle or to just keep food hot.

A double pot roll up blower stove

The double pot stove was designed to support a second pot and make use of the heat from the exhaust flame, steam, and hot gases.

Rollup wing-wall

Rollup wing-wall To ‘tame’ and ‘harness’ the tongue of flame I connected a rectangle of titanium foil to one of the C-Ring stove edge tubes. This made a hinged wall that I call, a ‘wing-wall’. The wall shielded the tongue of flame from wind gusts, gave the flame a controlled direction. It also provided heat protection for; the secondary pot handle, the blower/battery unit, and the cook. The wall could be hinged back and rolled up with the stove body for compact packing.

Swinging Wire Bridge

To finish the two pot stove, on the outer end of the wing-wall I formed another tube (as on the stove burner body) to support a second titanium wire bridge unit which can be adjusted (by swing action) to support a second pot and thus providing support for pots and pans of various sizes. The movable end of this bridge unit has a short bent foot to give it a larger ground bearing surface to support the pot weight when the stove is on soft ground.

A captive articulated ground peg of hardened stainless steel is on this foot and it allows the foot to be firmly fixed to the ground. Similarly, another articulated captive peg of titanium wire is used to peg down the stove C-Ring body.

These pegs require that the stove is set up on soil or firm sand or fine gravel. The ground peg arrangement can also accommodate the use of rocks to anchor the pegs on hard ground. The hinged connection of the wing-wall allows it to be hinged back around the outside of the stove body for quick and compact packing into a cooking pot or around another round object.

Flame guide refinement

My most recent two-pot ultralight blower stove designs have a flame guide option. This device guides the flame from the bottom of the primary pot on under the second pot without flames escaping between the two pots.

Keeping it all together

One weakness of these ultralight blower stoves is the potential loss of small parts or even leaving them at home! “Believe me, in this regard, I make an excellent test dummy” Consequently, I like to keep the; C-Ring, wing wall, two bridge wires and ground pegs all semi-permanently attached to one another. This means that the parts are less likely to be lost or left behind (I make similar arrangements for the blower unit and power cables etc for the same reason).”For the ultralight blower stove, this fixed connectivity makes the pack up more tricky, just like those impossible looking bent nail puzzles but it can be done.”

Mutual packing protection

For the ultralight blower stove, the core pot is made of very thin stainless steel or aluminium. Consequently, it needs protection from crushing to safely carry it in a backpack. For the open top of the pots, much of the crush resistance comes from the secure fitting of the pot lid (to form a full metal cylinder). Alternatively, protection can be provided by ‘nested’ packing of multiple pots inside another to provide strength. One pot can be put ‘bottom-up’ over another close fitting pot that is ‘bottom down’ and they give each other mutual crush resistance.

When such multiple pots are carried, ultralight DIY aluminium foil lids can be used and these can have removable lay flat handles to make the backpacking smooth, light, and efficient.

In either case the outside finish of the kit should have a benign surface that will not harm other items when backpacked together. I prefer to first pack the stove kit and pots inside a plastic bag to isolate any tar or soot smells. I then pack this bag inside a tight-fitting stretchy cloth bag with a drawstring and cord lock. The stretch of the bag keeps the top lid in place (for crush resistance) as well as keeping secure other lids or pans that may be packed on the outside of the outermost pot.

Oversize pot and pan option

Another versatile use of the ultralight blower stove can be to cover the stovetop and secondary cooking positions (if there is one) with one large pot or pan. Just this weekend I took the large stove on a family day walk where we had a cookout picnic lunch. Within minutes of arrival at our lunch stop in the bush, we had boiled water for a round of hot drinks. Then we had stir-fry vegetables and pasta with fish that was all cooked in one large frying pan over both the primary and secondary pot positions. The ultralight blower stove provided powerful, clean, gentle and trouble-free heat for rapid cooking of the meal. This was followed up with more boiling water for another round of hot drinks and a wash-up of the pan.

The bottom line is that almost any pot will work with an ultralight blower stove, even if a little less efficiently, so long as the pot is wide enough. There is so much excess power that the inefficiency of heat transfer does not matter.

Me

Fiddle Free Stove

This ultralight blower stove model was inspired by a walking friend who said that my stoves were ‘too fiddly to set up’. After overcoming the initial sense of disappointment, I designed this stove to have a large ‘one-piece burner’ with a larger single cookpot (1,000ml, ~100g). The big pot with its rebated bottom edge fits neatly into the top of the burner ring. The lid is a modified aluminium saucepan lid (from the opportunity shop) and I fit a low profile stainless steel ‘lay flat’ handle to it.

Because the burner has a bottom in it it is very suitable for use on rocks and uneven ground, is easy to set up and can be used for ‘leave no trace’ cooking. “Thanks for your critique Wendy”.

Snow stove

This ultralight blower stove is a derivative of the Fiddle Free Stove and has all the same ultralight blower stove functionality but it has extra features that enable it to be mounted high up on a bush pole that is driven into deep snow and then compacted with a little more snow. It also has an additional lightweight removable shelf and wall (that can pack inside the burner) that can support the protruding ends of the fuel sticks. This makes a practical alternative for use in deep snow if suitable rocks are not available for mounting.

A blower stove without a stove?

It is possible to use an ultralight blower stove fan to make an effective cooking stove using found materials? The simplest stove can be made from two long rocks spaced apart on the ground to form a pot stand. Feed sticks in at one end and put the blower fan at the other end and this makes a very efficient stove (Don’t use exploding rocks!).

Scraping a long trench between the rocks can increase the capacity of the burn chamber and longer rock lines can support multiple pots. If there are no suitable rocks then a trench will suffice. More ‘stove without a stove’ ideas are given in Rock-N-Hole Stoves.

Backup alcohol burner

 In pouring rain or a blizzard or when you can only have a ‘dingo’s breakfast’ ( a pee, a quick sniff around and a cup of coffee and maybe some muesli if you’re lucky) it may not be suitable to cook on wood-fired ultralight blower stove. I have found that a suitable small alcohol burner can suffice when used with the C-Ring Stoves, using them as a pot stand and windshield.

Custom booze bottle lid alcohol burner

The Trangia-style burner was wasteful of heat, too big to fit in with all the other stove components. It also is much heavier than necessary and eventually gets too hot to function correctly because of excessive heat feedback from the flame. A ‘booze bottle lid burner’ Patrick’s Bushcraft Youtube can be an efficient alternative. As is my usual wont, I have added a light, telescopic, stainless steel, riser to the lid to get that nice clean hot mushroom flame that hugs the bottom of the pot.

The second last word

I have had great fun with the ultralight blower stoves. They are the sweetest most versatile micro wood-burning device that I have used. Even the tiny blower fan and connecting pipes and manifold is an indispensable tool for starting campfires (or any other fire) under difficult conditions. On my farm, I even use it connected to a 2 m long pipe to burn out stumps. “Yes it is slow, but it beats getting the chainsaw into the soil!” The persistent controlled blast of air will rapidly and effortlessly breath life into remnant coals or a difficult to start a fire on a wet day and make it spread rapidly. For me, it is an indispensable tool to take when I go into the bush. Please see the following link of starting a fire with a USB fire blower.

The last word- the three in one camping stove

Do you enjoy going out into the freezing wilds to ski and play? Then my most recent tinkering has successfully combined a tent heater/cooking stove, an outside blower stove, and an alcohol stove. They all use the same burner chamber and together fit into the one tiny package that fits inside one, two, or even three nesting dinner pots (KISS tent stove).

I would welcome questions about the ultralight blower stove, supply of parts, suggestions for better explanations and critique of my technical explanations and reasoning. “Remember we all have the right to be wrong, it is a good way to learn.”

Tim

FAQs

In this cornerstone post. I have added this FAQ section below to collate your questions and my answers to make it a little simpler to follow particular threads. We will see if it works? I will also collate questions that are made in comments in other blower stove post if relevant.

Also, I have what I call a ‘pictorial gallery index‘ of my many blower stove posts that may help (web dummies like me) find answers to questions or even to frame your questions. The pictures give a flavour of the content of the post along with the words within the links.

Under the name of the questioner, I will repeat or paraphrase the question and under my name (Tinker) I will give my answer. I hope it makes for clear reading!

Nick: What are the dimensions of the stove when packed up?
Tinker: The stove packs up inside its custom 1L cooking pot that is 75mm high*150mm dia.

Nick: First, how hard is it to leave-no-trace with a blower stove? I would expect the main chamber and exhaust flames to share a lot of heat with the ground if not managed.
Tinker: In blower stove mode, I usually put the stove on the ground that has already been damaged or on a rock, sand or gravel that can not be damaged. The same applies to the flame exhaust area. An aluminium tart dish (~5g) could also be used to provide protection to the ground where the blower stove flames shoot outwards from the fuelling ports. Luckily most of the heat goes upwards and is quite capable of heating a second pot. A thick layer of ash or soil in the bottom of the fire bowl also makes an excellent insulator and makes the stove cook faster.

Nick: Second, What is your startup process for a blower stove?
Tinker: This is easy and a delight to do, with a little experience. Please see the youtube link below. It is a roll-up titanium stove without a bottom, but the principles are just the same. The stove with a bottom is easier to light and use and is better for leave-no-trace. The stove can even be picked up with pot tongs and shifted to a better place if required. I often do this while cooking on the stove beside a campfire or in a fireplace of a mountain hut.
https://www.youtube.com/watch?v=kddWIYA4ivI&list=PLVaCw7cPfpCx0eRmT_ghx9ZDZGLGNgJyM&index=6&t=0s

Nick: Lastly, what is the battery consumption like? mAh / minute of operation?
Tinker: Battery consumption is about 0.12 mA. without the LED lighting. I can get two to three hours of full power cooking from a good 18650 battery. On multiple weeks I have got, from one battery, a week of cooking including water sterilization when I have used my fan pulsing switch on the USB fire blower( I carried 6 batteries on three-week-long Hume and Hovel explores trail walk, just in case). For more details please see:
https://timtinker.com/extending-battery-life-for-blower-stove/

Bill: Thanks so much for sharing your development of blower stoves. I hope to build one soon. Do you think a controller like this would be useful: https://www.aliexpress.com/i/33050265798.html

Tinker: Nice USB stuff out there. I have no reason to think that it would not work. However, if it is USB ‘battery power’ that you are trying to save by speed control, I suspect that it is probably made to work on an unlimited USB power supply (at home). It consequently will probably not be very ‘power-efficient when out in the bush. I discuss this issue in another post https://timtinker.com/extending-battery-life-for-blower-stove/ and conclude that “…the quiescent and active current [of such devices] will largely nullify any battery energy saving.
On the other hand, if you just wish to down-regulate the burn rate or cooking temperature then the simple blower shutter works well but only saves about 10% when fully closed. The manually switched (bedlamp push button) works well and can extend the cooking time by about fivefold! I hope I have understood you and I make some sense. Where are you? Let me know if you would like to buy one of my blowers. I would be pleased to hear what your solution ends up being.