When a fire is producing excessive smoke, it is likely due to the condition of the fuel. It may be too green or too wet and so much heat is being used up in drying that there is little left over for volatization. The solution is to add good dry fuel on top of the smoky fuel and the products of incomplete combustion will be more completely burned in the improved fire.
Oxygen
The atmosphere generally contains about 20.9% oxygen and about 79.1% nitrogen. In the presence of oxygen almost all matter undergoes a change which is often termed oxidation. Oxidation can be as slow as rusting or as rapid as an explosion. With an increase in temperature, the rate of oxidation also increases. For each 10 degrees Centigrade rise in temperature the activity of molecules doubles. This accounts for the ease which a fire may be made on a summer's day at 20 degrees Centigrade as compared to minus 20 degrees Centigrade on a winter's day.
If the temperature of a fuel is raised continuously it will eventually burst into flame (the production of heat and light), an indication of its rapid reaction with oxygen. This is termed combustion. The rate of combustion is dependent on the ability of the molecules of fuel and oxygen to mix together in the appropriate proportions in spite of the interference from the nitrogen in the air.
In still air a fire will draw in surrounding oxygen through the circulation created by the hot convection currents (thermal column) rising above the fire. A fire suspended off the ground will burn better than one on the ground. For this reason a fire built on a mound will burn better than one in a hole.
A strong wind will force far more oxygen on a fire than convection draw could provide and thus make the fire more intense.
The thermal column formed above a flaming area establishes an airflow so that the oxygen is brought to where it is needed for mixing. The mixture thus formed has a flammable range within which it will burn. If the mixture is too lean in oxygen or too rich in oxygen for a certain concentration of fuel vapor, no combustion will result even if an open flame is present.
The too rich in oxygen phenomenon is often encountered in lighting a wood stove. When the door is open there is usually an imperceptible draw through the stove up the chimney. When the fine kindling is lit and the door kept open the fire does not seem to want to go. When the door is closed and the draft is reduced the kindling roars into flame.
It is interesting to note that when the oxygen supply, for any reason, drops from its 20.9% to about 15% combustion ceases due to the smothering action of the nitrogen in the air.
Ignition Continuity
Once combustion starts and is given ample oxygen, it becomes self-supporting:
a) as the fuel burns it creates more heat.
b) the increase in heat raises more fuel to its ignition temperature.
c) additional oxygen is drawn in by the convective column of heat forming above the fire. In a raging conflagration a windstorm can be observed drawing air to the burning source.
d) the oxygen increases the rate of burning and more fuel becomes involved.
e) this chain reaction continues until the fuel has been consumed. This is known as a fuel-regulated fire. Outdoor campfires are fuel-regulated in that you make it big or small by adding or withholding the fuel. In a stove the fire is oxygen-regulated, in that you can vary the air supply to make the fire burn slower or faster.
Heat Transfer
In an open fire heat transfer is carried out by either convection (flame created thermal column) or by radiation, with conduction generally being insignificant.
Heat Transfer By Convection
Generally, heated air or other gases produced by the burning process, being lighter than the surroundings, flow upward to warm or to dry and fuel above or even bring it to a kindling temperature. This transfer of heat through a circulation medium is termed “heating by convection”. It is important to realize that when fuel is wet or green it must be put on a fire so that this convective heat can dry it out in anticipation of when it is needed.
Heat Transfer By Radiation
Any hot object sends out invisible infra-red waves that warm anything that intercepts these waves (if something is white hot it can emit ultraviolet rays that are even hotter, but this likely will never be encountered in a campfire situation). When you stand near a fire a wind may waft some convective heat your way but it is the radiant heat you should most benefit from. It is much like the warmth that we feel when the sun shines on our skin or on a dark item of clothing. Radiant energy can be blocked by a reflective material that bounces back these rays. A dark surface absorbs the rays and a light surface reflects them.
The Physics of Fire
In all these cases a fire occurs when a reaction is started that gives off more heat than was required to start it (exothermic), thus the reaction spreads through all the available combustible material or until the total heat falls below that needed to sustain the process. As heat radiates away from the point of fire in all direction, much of it is dissipated out into space (entropy). When two or more burning objects are placed close together, each captures part of the others heat, helping to sustain the fire. In the case of fires based on the oxidation of organic (carbon base) materials, if oxygen is used up, the fire will also die. Therefore, burning logs should be placed about an inch apart to insure enough oxygen while maintaining heat. A quick, bright fire requires lots of air flow, a slow hot fire occurs with minimal air flow.
N. Kidder
THE HAND-DRILL AND OTHER FIRES
By David Wescott
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The mastery of fire technology, for many of us, has been an interesting devolution. For years it was thought that mastery of the hand-drill fire was beyond mere mortals and that it would never be tamed. However, once that barrier was breached by the likes of Scott Kuipers and Mike Clinchey (both masters of the hand-drill), the utility of the hand-drill has much surpassed the good old bow-drill that dominated the majority of teaching venues for years.
Little did we know that the level of technology and lack of physical control had impeded our regression to this simpler skill. With the bow-drill, the parts are complicated and precise, the body position and control is difficult, and these problems are compounded when the two are put together with a lack of understanding on what makes a friction fire work in the first place.
Fire By Friction Anywhere
Making fire by friction is a deceptively easy process once the principles are understood and the technique well practiced. It's a trip to watch a master walk over to a bush, snap off a twig and begin rubbing it on a log until smoke begins to rise from the resulting trough. Or a straight twig is cut, roughly straightened, and spun between the palms, while resting on a softwood hearth to create that magic spark. Or better yet, splitting a section of bamboo, scarping off the lacquered layer to be used as tinder, creating a notch with a slice of rock, and then rubbing the notch along the edge of the bamboo until the tinder ignites.
The materials may vary widely, and the technique corresponds to the materials, but the principles of what allows us to make fire by friction is the same wherever you go, with whatever materials you acquire. Bow-drills are still the best for overpowering inferior materials, or inclement weather. But, when the woods are dry and good materials are available, why waste time climbing the evolutionary ladder of technology to a method that isn't nearly as satisfying ?
Here is what you need: materials - read what Dick Baugh has to say about what will work and what won't. Woods that produce a fine powder (not granular flakes) are needed - good tinder is a given; tools - a simple cutting edge is all that's needed to rough out shapes and create required notches and/or grooves - parts for these fire sets are simple and need little alteration from their natural form (not so with the bow-drill); technique - practice-practice-practice. Team work is a good idea, as the energy and frustration quotient parallel the learning curve...little skill= high rate of failure and big blisters.
Specific parts are very simple: 1. the manual piece which is spun or rubbe
d back and forth - spindle, plow, saw; and 2. The stationary piece which is held in place - hearth, log, split bamboo section.
Technique: 1. start out slow to warm up the set; 2. maintain pressure at the contact points; 3. gradually speed up and watch for ashes to accumulate (check them to see if they are powdery or granular); 4. increase speed and pressure; 5. don't forget to breath (by now you should be going anaerobic - carefully and quickly switch with your partner if needed) and watch for telltale smoke. Once the smoke appears, watch to see if the wisp comes from the pile of ash, not the set. Stop for a second and watch for smoke to rise from the collected ash. A slight blow or breeze should result in the spark glowing from the pile. Take a few breaths and let the ashes concentrate into a solid coal. Now you're ready for fire!
Hand-drill "master", Scott Kuipers introduced us to such innovations as floating the hands and working up and down the spindle without ever removing the hands from the spindle.
Tools of the trade - hearth, spindle, and blisters.
Create a small depression to hold the spindle in place.
Once the hole is "set" by a couple of passes, carve a small notch into the center of the hole to allow the ash to accumulate.
Focus On The Hand-drill
The hearth and drill can be made of the same materials, but usually the long, straight spindle is harder to find. The bottom line is that all materials need to be dead and dry. The hearth needs to be quite soft (split yucca stalks work great) and at least twice the width of the spindle base. The drill needs to be as straight as possible and from 18 to 30 inches long. The diameter may vary, 1/4 and 3/4 inch in diameter (There has been a long and unsolved question as to what works better - a small spindle that spins faster, or a fat spindle that provides more surface area for friction...any suggestions?) I might say that a very small spindle may be harder to learn with, and also allows the palms to rub together, resulting in huge beginner blisters. If a long spindle is unavailable, a soft plug may be added to spindles of harder materials to get the set you need as well as extend the life of the materials available to you.
Some materials may be: hearth - poplar, clematis, yucca stalk, cottonwood root, some willows and poplars; spindle - cattail, seep willow, teasel, sunflower, prince's plume, yucca stalk. You're looking for very soft yet stable materials. The should be light, dry, and solid not rotted.
Split the wood you chose for the hearth. One flat side will do, but you may flatten both. Leave hearth about 1/2-3/4" thick. Make a dimple in the middle of the hearth into which the spindle may be seated. The spindle should be scraped and straightened as well as possible.
Once the fire set is ready and the tinder bundle and fire lay are all in place, get comfortable and start to drill. The position you choose is up to you. Notice that Scott sits down, using his arms to do the work, while others kneel and use upper body weight to help with the process.
The trick to getting a spark is to start out slowly and spin the drill to warm it up. Start at the top of the spindle and work all the way down. Some pressure should be maintained at this point to keep the end from polishing. Once the set is warm, increase speed and pressure. Lean into it and maintain pressure. The spark comes from a combination of speed and pressure.
To avoid tiring too quickly and reduce blisters, spit on your hands to give you a better grip without having to press inward too much. Use both arms equally. Flare the hands slightly and use the entire heel of the hand to avoid rubbing the hands together. Start out slowly and give it all you've got later in the process.
One other trick is to avoid pulling the spindle from the hearth or taking to much time returning to the top of the drill after each pass. Maintain timing to maintain the level of heat in the set and the ash. Move one hand at a time back to the top of the spindle and go again.
After one or two passes, cut a notch into the side of the hearth that extends into the middle of the whole created by the drill. This allows the ash to collect and increase in heat and mass as the spindle and hearth wear away wood fibers. Once the correct temperature is reached to kindle the coal (7-800 degrees, Baugh), the fibers will ignite and begin to smolder. At this point, sit back, tell a joke and let the coal grow and solidify. Not until then should the coal be transferred to the tinder bundle or transportation "match".
Making fire by friction is extremely satisfying process. The magic created by building your own set, mastering the technique, and then settling in to enjoy a cozy campfire, is truly one of the greatest of woodcraft skills that everyone should know. DW
Hold the hearth in place with the foot.
Continue to spin until smoke begins to rise from the pile of ashes. Bear down and increase preassure and speed at the last minute to get a coal.
Resist the urge to be in a hurry this point. Allow the ashes a chance to glow and condense into a coal. Use the knife to release the coal if it sticks in the notch.
Working as a team allows partners to use maximum effort for short bursts and then get a rest. try alternating every 2 or 3 passes to avoid exhaustion.
With the fire plow, the moving piece is moved back and forth in a trough created by the friction. There is no notch required, as the ash collects at the end of the trough.
The fire saw hearth is also the moving piece. The tinder is pressed into the concave side of the split bamboo, and the notch in the convex side is rubbed along a sharp edge on the staionary piece. The ash collects in the notch and ignites the tinder held in place by a small stick.
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Tips for First Time Hand-drill Friction Fire Makers
Text by Paul Schweighardt, ©1995
1 .Your biggest chore will be finding the right materials in your part of the world. If possible, find out what the local ancients used; they knew best since their survival depended upon these materials.
2. The char you produce will be your best clue as to whether or not the materials you have chosen will work. If your hand-drill is producing large amounts of very finely textured char quickly, then you have the right materials.
3. Use only very dry materials to begin with. Once you have become proficient in fire making, then you can experiment with damp, green or wet materials.
4. Choose your place well. Your area should be dry, sheltered from the wind, and clear of debris.
5. When twirling the spindle, twirling speed should be fast but not furious. Breath calmly and evenly,
6. Use only your palms to twirl the spindle, rather than letting it roll out onto your fingers. You will maintain greater speed and control this way.
7. Bear down on the spindle as you twirl it. Downward pressure is equally important as spinning speed. One without enough of the other produces no results.
8. Once you have your smoldering ember, remain calm. The ember will burn for quite awhile, giving you plenty of time to carefully place it into the tinder nest and gently fan it into flames.
9. Make fire in a responsible way so as not to cause bush or forest fires.
10. All motions should be performed in a calm, supple and graceful manner. Experiment, persevere and good luck!
* * *
THE GOYSICH HAND-DRILL
By Jim Allen
* * *
For those of you who despair over being unable to start a hand-drill fire, take heart—there is now an alternative! I'd like to tell you about a hand-drill method that is easier to do, requires no cordage, and can be set up in a few minutes.
The discovery of this method began several years ago, when I was visiting my good friend, Mike Goysich, in Lafayette, Indiana. Mike had been practicing the mouth drill method of fire starting, and had met with good success. I had always found this method to be awkward at best, and downright torture at worst. Nevertheless, Mike demonstrated his skill, and in the conversation, we began to brainstorm friction fire techniques. At this point I am not sure who came up with the technique I am about to present, but I've always attributed it to Mike. As Mike is now diseased, I have decided to name the technique after him,
as I'm fairly certain it was his idea.
The first step is to obtain a pole or log of approximately 25 lbs. This weight could be adjusted up or down according to ones strength. Nest, obtain a suitable spindle of mullein, yucca, willow, etc. The spindle can be anywhere from 8" to 24" long. Then construct an ordinary fireboard of suitable materials. The last step is to obtain four stakes of about 2-3 feet in length and a rock or log to use as a mallet for pounding stakes. (More than four stakes can be used as needed).
Primitive Technology Page 8