Smokeless fire?

[gillmacca]

Cn anyone give me advice on making a smokeless fire?
I know you can use animal droppings, but is there anything else you can use (things you would find on the land)?

[Realgar]

Charcoal is about the best - truly smokeless. Animal droppings will smoke a bit. Any well seasoned hard wood should give a very limited amount of smoke.
In my ( limited ) experience dry gorse does pretty well though it doesn't last long. The hazel I fuel the kiln with doesn't smoke once it's lit properly but for the first five mins you might as well be using tyres so I'd suggest getting a small fire burning hot and fast before fueling up with something more substantial.

An alternative is the old tin can brazier with a short chimney that allows the smoke to diffuse through wet moss before escaping, this can be done either using more can to make a chimney or more likely by cutting a groove into an earth bank and covering it to make a channel. The longer the chimney the less smoke.

The trick is to keep plenty of air circulation and let the fire burn as hot as possible. The difficult bit is getting it lit without too much smoke.

Planning on cooking somewhere you shouldn't?

Realgar

[Gary]

I would say animal droppings unless totally dry would be very smokey!

There is no such thing as a totally smokless fire however you can get a near as damn it by splitting all your wood and burning only the dry heart wood but this is a lot of effort for little reward.

[gillmacca]

Charcoal is about the best - truly smokeless. Animal droppings will smoke a bit. Any well seasoned hard wood should give a very limited amount of smoke.
In my ( limited ) experience dry gorse does pretty well though it doesn't last long. The hazel I fuel the kiln with doesn't smoke once it's lit properly but for the first five mins you might as well be using tyres so I'd suggest getting a small fire burning hot and fast before fueling up with something more substantial.

An alternative is the old tin can brazier with a short chimney that allows the smoke to diffuse through wet moss before escaping, this can be done either using more can to make a chimney or more likely by cutting a groove into an earth bank and covering it to make a channel. The longer the chimney the less smoke.

The trick is to keep plenty of air circulation and let the fire burn as hot as possible. The difficult bit is getting it lit without too much smoke.

Planning on cooking somewhere you shouldn't?

Realgar

When camping i much prefer to cook over a fire that a stove, gives it a better taste,

[NickBristol]

I would say animal droppings unless totally dry would be very smokey!


Animal droppings that aren't totally dry are pretty hard to pick up tho...apart from on the bottom of your shoe :wink:

[Gary]

awwww :yikes:

I meant sun dried and not moist on the inside - although that sounds just as bad!

[Paganwolf]

smoldering dried herbivore turd is excellent for keeping the mozzies away :shock: and probably anyone else for that matter :rolmao: :wink:

[bushwacker bob]

Almost smokeless fire can be achieved by only using dry deadwood and stripping all the bark,same effect as gary as he only uses the heartwood.
Very useful if one should accidentally NOT wish to be found :o):

[Tekeeler]

If you have the time to do the preparation, bundles of birch twigs that are fully dried will do the trick. Obviously this isn't too spontaneous but they will burn very nicely and give off an extraordinary amount of heat. Preparation is simple. Collect the birch branches, anything below about 3/4" should do and bundle up with twine (spruce roots to be be the favoured bit of kit if this is to be totally natural). They do need to be left for at least eight months in the total dry. These bundles (or faggotts) have their place in history. They were used in the top of execution fires to give off a searing heat that would not aid the unfortunate's suffering by producing a smoke that could knock them out. They simply burned them without smoke. Ouch. Possibly where witch's brooms came from as the process for these is much the same. :yikes:

[Odie]

OK, I am pretty new to the bushcraft scene, but I do know a bit of chemistry.

Basically, smoke is the result of incomplete combustion.

Charcoal burns with very little smoke because it is a chemically simple fuel - basically simple hydrocarbons with a few impurities. When it combusts, ie reacts with oxygen, it forms simple molecules such as carbon oxides (CO & CO2) and water vapour (H2O). Both of these gasses form relatively easily.

The problem comes when the fuel becomes more complex. The heat generated by natural combustion may not be enough to reduce the more complex hydrocarbons (such as resins, oils, etc) into the simple gases - in simple terms the energy of natural combustion is not sufficient to break the molecular bonds of such compounds. This results in these complex HCs being liberated as gas or vapour. There will also be some solid compounds that remain unreactive or are formed from incomplete combustion reactions, soot, ash, etc that will add to the particulate component of the smoke.

So basically, the hotter the fire the less smoke you will get. And to get a hotter fire you need to get as much air to the fuel as possible.

Not really an answer but more of an insight into the problem :?:

[Tore]

Trick is to light the fire upside down...
That would be to light the fire at the top. Build the fire with the same length of "logs" or branches, and lay side by side and build layer on layer. On the top you light the fire with kindling (?). It is the water in the wood that make the smoke (to put it simply) in a regular fire the water cool the flames. If the fire is started on top the water will not cool the flames in the same extent, and the fire will dry the wood.
About the same way as if you want to burn fresh birch wood in cold weather.

Tore

[MarkG]

In WW2 there were some people hiding deep in the woods. Smoke would have given there location away, so they built a stove with a long horizontal chimney covered in earth to cool the smoke and then filtered the smoke through a big pile of damp moss IIRC.

Not really applicable to us for making a brew but if you've got a long term spot it could be an idea.

[Moine]

Gillmacca,

As it's forbidden to light fires around here most of the time, I've been practicing those ancient indian scout things regarding smokeless/invisible fires.

It truly is an art more than a science, and it does requires a lot of experience (which I am only slowly gaining...), but here are a few tricks that can speed up your learning:

- Any moisture in your wood will create vapor, which looks very much like smoke... Pick standing dead, bone dry wood only, and remove all the bark. If you're on a river, wood from old log jams usually are good, as they are clean from any bark and ca be found super-dry. They can be hard to ID correctly though (see below).

- some woods will produce very little smoke WHEN DRY. The three first that come to mindmind are maple, green oak and tannin-free oaks (4-5 years wash/dry wash/dry cycle) and beech/birch (but those tends to "pop" a lot when burning and each time it does, it creates smoke).
Stay clear from all conifers, as they can contain pitch that will burn well and very hot, but will produce black smoke that is highly visible (especially over snow).

- if you want your fire undetected, you need to hide the flames too (especially at night). That's why I use a fire hole (basically you dig a 15-20cm pit vertically, and then a perpendicular feeding tunnel that goes downwards like a tunnel and joins the main pit. Like a chimney and a stove door, if you want. This hides the flames pretty well and it also concentrates heat a lot so you get less smoke, as the wood burns completely. It's great for cooking, if you're not the proud owner of a billy can ;) But you won't get much heat from that on cold nights (unless you sit over it or somthing :D).

HTH, and I'm interested in any tips & tricks regarding this. I still often fail miserably to light that smokeless fire...

David

[Tantalus]

didn't our ancestors make fires from bone and bone shavings?

as i understand they are hot and pretty smokeless though i never tried it

Tant

[ChrisKavanaugh]

Yes they did. They are called BONFIRES. Aside from the above inputs, location, like real estate is still everything. If you are attempting to reduce your visibility, obviously camping in the middle of a meadow is a poor choice. Remember too, fire producessound and smell. The old indian adage is good to remember. White men build big fires and spread out. Indians build a small fire and sit close.

[arctic hobo]

Here's a (stupid) idea: Get a steel plate, and make your fire on it. Glue all the logs with cyanoacrylate in every place possible. Then hold the steel plate upside down and all the smoke will rise and solidify on the plate instead of going into the air. Problem solved! :rolmao:

[RovingArcher]

Gillmacca,

As it's forbidden to light fires around here most of the time, I've been practicing those ancient indian scout things regarding smokeless/invisible fires.

It truly is an art more than a science, and it does requires a lot of experience (which I am only slowly gaining...), but here are a few tricks that can speed up your learning:

- Any moisture in your wood will create vapor, which looks very much like smoke... Pick standing dead, bone dry wood only, and remove all the bark. If you're on a river, wood from old log jams usually are good, as they are clean from any bark and ca be found super-dry. They can be hard to ID correctly though (see below).

- some woods will produce very little smoke WHEN DRY. The three first that come to mindmind are maple, green oak and tannin-free oaks (4-5 years wash/dry wash/dry cycle) and beech/birch (but those tends to "pop" a lot when burning and each time it does, it creates smoke).
Stay clear from all conifers, as they can contain pitch that will burn well and very hot, but will produce black smoke that is highly visible (especially over snow).

- if you want your fire undetected, you need to hide the flames too (especially at night). That's why I use a fire hole (basically you dig a 15-20cm pit vertically, and then a perpendicular feeding tunnel that goes downwards like a tunnel and joins the main pit. Like a chimney and a stove door, if you want. This hides the flames pretty well and it also concentrates heat a lot so you get less smoke, as the wood burns completely. It's great for cooking, if you're not the proud owner of a billy can ;) But you won't get much heat from that on cold nights (unless you sit over it or somthing :D).

HTH, and I'm interested in any tips & tricks regarding this. I still often fail miserably to light that smokeless fire...

David

Good info David. I have trouble too, especially if all I have to work with is fuel that doesn't lend itself to that type of fire. If I would have to sneak a fire and know that the fuel isn't the best, I'll forgo the fire unless I really need it.

I find that it also depends on how the wood is presented to each other and it's size. I was taught to start with small twigs that are very dry and have been debarked. Place the fuel in such a way that it resembles a tipi. This maximizes the amount of air. If the fuel is carefully chosen, there is very little smoke to be seen from a distance and the flames will be hidden from view, because of the Dakota hole, which David described. Build the fire up in the same manner (tipi), gradually increasing the length and diameter of the fuel until the fire has reached the desired size.

Try not using a fire during the day. Even a smokeless fire puts off smell as the exaust of the fire travels on the wind and it is much less likely that someone will travel after dark to find a bit of fire smell. Placing a shelter around the Dakota hole will help to confine the warmth thrown by the small fire, as well as help to conceal the reflected light.

[Moine]

Good info David. I have trouble too, especially if all I have to work with is fuel that doesn't lend itself to that type of fire. If I would have to sneak a fire and know that the fuel isn't the best, I'll forgo the fire unless I really need it.

I find that it also depends on how the wood is presented to each other and it's size. I was taught to start with small twigs that are very dry and have been debarked. Place the fuel in such a way that it resembles a tipi. This maximizes the amount of air. If the fuel is carefully chosen, there is very little smoke to be seen from a distance and the flames will be hidden from view, because of the Dakota hole, which David described. Build the fire up in the same manner (tipi), gradually increasing the length and diameter of the fuel until the fire has reached the desired size.

Try not using a fire during the day. Even a smokeless fire puts off smell as the exaust of the fire travels on the wind and it is much less likely that someone will travel after dark to find a bit of fire smell. Placing a shelter around the Dakota hole will help to confine the warmth thrown by the small fire, as well as help to conceal the reflected light.
Hey brother (cousin? ;)),

Good info as well. It's true that a shelter around the fire hole works great, both for concealing heat and light. I should have thought about it. It's also great when you're in a brush shelter as it will prevent a lot of trouble with shelter fires. However, every time I tried that, I had trouble with... smoke inside the shelter :rolleyes:

With a loose brush shelter it's great, but with a small tipi, canvas tent or anything waterproof, you get a lot of smoke inside, unless you raise your fire a feet or two off ground level and create air intakes at about the same height. The smoke usually doesn't fall down further than the top of the flames, and never lower than the air intakes, as colder air will fall down on the tipi floor before being sucked in by the fire, thus raising the smoke level.

Complicated stuff... That's probably why I like those small wood stoves and chimney holes so much ;)

Cheers,

David

[match]

One way to make a smokeless fire (although one that take s abit of effort) is to dig a hole into the side of a bank, and then dig a long tunnel leading from this hole up and away further into the bank, exiting the bank higher up the side. At the exit, stuff the tunnel loosely with damp grass, moss etc. Then build your fire in the hole. As the tunnel acts as a chimney, the smoke will largely cool and stick to the sides of the tunnel if it is long/damp enough, and also to the grass/moss it fiulters through near the exit. This approach allows you to build a reasonable fire with very little smoke at the exit. The only things to note are that it may smoke quite a lot at first, until you get the chimney drawing properly, and you may need to keep wetting the grass 'filter' if it dries out or it too can heat up and begin to smoulder!

[Moine]

Interesting !

I never tried that one. I'll give it a go tomorrow.

What do you use to dig that chimney? How long should it be?

Thanks,

David

[Carcajou Garou]

We build a small stone niche with a "clean flat stone tablet" over top a "small" dry wood fire, and place it under a tall well branched fir tree, the fire would heat the stone and the heat would sink in the stone tablet, we could "cook" on this stone what little smoke would curl and adhere to the bottom of the stone. Whatever smoke escape the stone niche would rise and be disapated among the branches. Still have a problem with the smell at close range.
just a thought

[Moine]

Salut Carcajou Garou :)

LOL -- J'ai pas peur des ours, mais les carcajous je me sauve en courant ;)

Nice tip. I'll try it as well. I think the smell is just about impossible to hide... especially on bad weather days where the smoke is sticking to the ground...

Salut,

David

[match]

Interesting !

I never tried that one. I'll give it a go tomorrow.

What do you use to dig that chimney? How long should it be?

Thanks,

David

I've only tried this in practice once, and I had a folding shovel with me :) -I suspect that any kind of branch would do if the ground was soft enough, but then it might take you a while to complete!

When I made the last one, I made the tunnel about 1.5m-2.5m long, and probably about 20cm wide, tapering towards the top to get it to draw better. Took about half an hour to dig it out properly, but it worked quite well, although I over-stuffed the chimney with damp grass at first, so there was a huge amount of smoke to start with when it first lit and failed to draw. I guess this is always a problem with any fire as it will always smoke until it really gets going...

[Buckshot]

Would an easier option be to dig a trench and then cover it over or would that not work? :?:

Of course the trench would have to be deeper at one end to allow it to draw

Cheers

Mark