|Table of Contents for Caveman Chemistry: 28 Projects, from the Creation of Fire to the Production of Plastics|
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Few people in the twenty-first century remember how to make fire, to really make fire, from scratch, as it were. If you are to make the long journey from caveman to chemist, you must learn this skill, which precedes all others. To make fire you need wood and air, both of which are easy to come by, but the central problem of fire-starting is getting enough heat to initiate the combustion of charcoal. The easiest, though least convenient solution, is to simply wait for a lightning strike as the original Lucifer did. Once people began making stone tools, it became apparent that certain stones sparked when struck together, and that if you caught the spark in a flammable material, you could start a fire. The modern cigarette lighter is the child of this technology. In addition to stone, wood itself was used for making tools, though it leaves little evidence in the archeological record. When wood is rubbed together, the friction generates heat, sometimes enough heat to ignite the wood. The modern friction match is based on this phenomenon. With the invention of the glass lens in the fifteenth century, fire could be started by focusing the light of the Sun on a combustible material, a technology that has delighted children and terrified ants ever since.
None of the ancient methods of fire-making are easy to learn, and all of the modern methods are so easy as to be trivial. For this book, I wanted a method which would be easy enough for most people to master, while preserving some of the challenge of traditional methods. Flint and steel is not too demanding but it requires steel, which was unknown in Paleolithic times. The magnifying glass, though entertaining, is also too recent a development for our purposes. This leaves fire by friction, the method I have chosen for consideration. One of the most popular tools for making fire by friction is the bow-drill. Reliable, portable and quick, it has remained my favorite method over the years, but like learning to ride a bicycle, it requires practice. To facilitate this practice I have devised "training wheels," as it were, for the bow-drill.
Figure 1-4(L) shows the complete fire kit. A brief overview of its parts and operation will be given first, with details to follow. The "training wheels" consist of the guide (a) and supports (b), all cut from standard 2x4 inch lumber. The guide is 9 inches tall and has two holes drilled at right angles to one another. The vertical hole is 5/8 inches in diameter and approximately 4 inches deep. The horizontal hole is 1 inch in diameter and goes completely through the guide. The holes must be drilled so that they intersect one another, that is, so that you may look down through the vertical hole into the horizontal one. The four supports are 14 inches long and must be screwed or pegged to the guide and to one other so that they securely hold the guide upright.
The vertical hole in the guide accommodates the spindle, (c), a 9-inch length of 5/8-inch diameter hardwood dowel rod. Such rod can be purchased inexpensively at hardware stores and craft shops. Since the spindle will be gradually consumed, you should have several of them on hand. The spindle should turn freely; if it sticks, enlarge the vertical hole with sandpaper until the spindle is free to turn. The top of the spindle will be held by a block, (d), a piece of wood with a shallow hole large enough to hold the spindle without binding. To keep from burning through the block, this hole should be drilled large enough to snugly fit a half-inch copper "endcap," available wherever plumbing supplies are sold. The inside of this endcap should be lubricated with fat or oil so that downward pressure may be applied to the spindle as it turns. In addition to the spindle and block, you will need a bow, (e).
It is not necessary that the bow be either flexible or curved. In fact, a 3-foot length of 5/8-inch diameter dowel rod will work admirably. Your bow will need a bow-string, for which a 6-foot length of 1/8-inch diameter nylon cord will serve. The bow needs one hole at each end large enough to accommodate the nylon cord. The cord is knotted at one end, passes through both holes in the bow, and is simply wrapped around the bow at the other end, allowing the tension of the bow-string to be adjusted. The bow-string will be wrapped around the spindle in such a way that motion of the bow turns the spindle.
Figure 1-4 shows the fire kit in operation. The left foot is placed on the support with the shin parallel to the guide. The left hand, braced against the knee, grips the lubricated block and applies downward pressure on the spindle. The bow is held parallel to the ground with the right hand and as it moves back and forth, the spindle turns freely in the guide. The lower end of the spindle presses against a piece of wood, the fire-board, which sits in the 1-inch hole in the guide. It is friction of the spindle against the fire-board which will produce the heat needed for our fire.
Not just any wood will work for the fire-board; it needs to combine strength, flammability, and low density. If you choose the wrong wood, your path will be filled with nothing but frustration. When looking for fire-board materials, low-density wood is best, as its low thermal conductivity allows heat to build up faster than it can be carried off. Think balsa, not mahogany. I have found yucca, shown in Figure 1-5(L), to be an excellent choice, and it is commonly available throughout North America as an ornamental plant. It can be recognized by its tuft of leaves at the base, its stalks reaching for the sky, and its fist-shaped fruits. Harvest the stalks in the fall, after the fruits have fallen. Mullein, shown in Figure 1-5(R), is another wood suitable for the fire-board. Strip off the leaves and let the stalk dry. Whichever wood you choose, cut it into short lengths that will fit into the 1-inch hole in the guide.
Now that the overview is complete, let us look at some details, starting with the bow. Figure 1-6(L) shows the far end of the bow, where the bow-string is knotted. The bow-string passes through a hole in the bow and is wrapped once around the spindle in the direction shown; if the bow-string is wrapped in the wrong direction, it may bind. The bow-string passes from the spindle through the hole in the near end of the bow. With the bow at an acute angle to the ground, the bow-string is pulled as tight as possible and then wrapped around the bow, forming a handle, as shown in Figure 1-6(R). Wrapping the bow-string rather than knotting it allows its tension to be re-adjusted quickly. When the bow is brought parallel to the ground the bow-string will come under tension, gripping the spindle tightly.
Figure 1-7(L) shows the "business end" of the spindle, the end which contacts the fire-board. A fresh spindle will be white and its end flat, but as it is used the end will char and assume a conical shape. Several fire-boards may need to be consumed before this ideal condition is established. Figure 1-7(R) shows details of the fire-board, with a notch, or chimney, cut into the end and a hole burned into the top by friction with the spindle. This particular fire-board has already made a fire and consequently its hole is relatively deep. I pre-notch my fire-boards and place them into the guide so that the tip of the spindle is near the vertical chimney. As the spindle burns a hole in the fire-board, charred wood dust, or punk, spills out of the chimney. It is this hot punk which will give birth to the ember.
Figure 1-8 shows the fire-board with its chimney in the guide. As the bow turns the spindle and pressure is applied with the block, the fire-board will begin to smoke and punk will spill from the chimney. If the pressure from the block is too light, no smoke will appear; if it is too heavy, the spindle will burn all the way through the fire-board before the punk catches fire. Therefore heavy pressure may be applied until smoke appears and then only enough pressure to maintain a thick, heavy smoke. The optimal bowing technique is to use long, smooth, steady strokes rather than short, rapid ones. Two or three strokes per second are quite sufficient. Try to make the pushing stroke with the same speed and pressure as the pulling stroke. The bow should move parallel to the ground and alongside your hips, rather than into your stomach. If you manage the block and bow gently and with great skill, the smoke will become thicker and thicker until the pile of punk itself begins to smoke. When this happens, stop bowing and blow on the hot punk; if blowing on it increases the amount of smoke, the punk very likely contains an ember. Keep blowing until the ember appears, as shown in Figure 1-8(R). A natural Lucifer may get an ember from the very first fire-board, but most people will go through two or three of them before achieving success. Once you have learned to make fire with the guide, you can try doing it au naturale; the guide will have trained you in the proper technique.
There is no room for equivocation. Either you have brought a red-hot glowing ember into the world or are content to live in darkness. Having succeeded, you should record your exploits in a notebook. Appendix B describes a suitable format. Describe your procedure in sufficient detail that you would be able to use it to reproduce your performance at some later date, for experimental reproducibility is one of the most important I-deas in science. Take one of your living embers and burn a hole through a page in your notebook as an everlasting witness to your achievement.
Throughout this book I use the word caveman in a gender-neutral sense. I prefer the ring of caveman and human to caveperson and huperson.
Throughout the book I use both English and metric units, as convenient. Chapter 3 will discuss unit conversions so that people may adapt projects to the materials available to them.
Left and right may be reversed for left-handed Lucifers.