So you’re lost in the woods and hard at work building (insert your name here)-andria when you realize that you could really use a slingshot to catch dinner. No problem. A slingshot is a pretty simple piece of technology after all. You spend some time searching for a good “Y-shaped” stick and use a little piece of leather, some leaves, or a piece of your sock to make a pouch. So what about the rubber-bands?
When you consider the levels of various technologies, there are more things to take into account than the simplicity of the machine or the number of parts. In the case of a sling shot, there are only three parts: a shaped stick, a patch of leather, and two bands of rubber. Sounds simple right? This should be considered a basic, primitive technology. But there is a catch. If the wilderness you are lost in resides in part of the English speaking world, you won’t have access to rubber for a long long time.
Rubber is essentially congealed tree sap, but the trees it grows on are now almost exclusively grown in south-east Asia. That’s a long way from land-locked Utah. The raw resource needed to build a slingshot is unavailable to us here.
So if we were to place the slingshot on a technology scale, where would it fall? Well, before we can build a slingshot, we need trade routes that can safely make it to Indonesia and back. That means we need the science of navigation to be top notch to cross the Pacific Ocean. Navigation requires astronomy, charts, possibly a compass, and all that is just to know where to go! Then we get to the ship itself. Building a ship to cross oceans with a cargo is no mean feat. You need advanced woodworking techniques (iron tools would really help), textile technology for sails (requiring looms, spinning, cultivation of fiber crops, and a whole lot of spare time, which means some division of labor), and overland transportation for the lumber and supplies to the shipyard. You are not going to do all this yourself in one lifetime, so you would need to organize a society with hundreds of skilled laborers willing to work together on this massive project. This means that you not only need a whole lot of technology and a lot of time to build a slingshot, but also an army.
How advanced then is a slingshot? That depends where you live. If you are reading this in Indonesia, it’s pretty basic. If you live in Utah on the other hand, a slingshot is higher technology than high-seas navigation and a steam engine.
So as you look at that tasty squirrel on the branch and wish for a slingshot, what are your options? You can build an entire civilization to solve the problem one way, or you can spend 30 minutes making a shepherd's sling to slay that bushy-tailed goliath. You could also make snares or traps from string and bits of wood or even an atlatl or bow and arrow. Those solutions solve the same problem, but at a much lower level of technology and, therefore, at a much lower cost to you. You get to eat squirrel now, and if you really want to establish sea trade with Thailand, you are welcome to do so at your leisure.
But let's say you have a set of problems that really need rubber and no currently-existing substitute will do. Such was the problem the United States faced at the beginning of World War 2. Numerous military-essential pieces of gear required rubber, including vehicle tires, combat boots, seals in machinery, machine belts, and much much more. Without rubber, the US could not fight, and Japan secured a near monopoly of the natural rubber supply as they conquered much of south-east Asia.
As they say, necessity is the mother of invention, and invent they did. Though the rubber tree, Hevea Brasiliensis, is the best known and most economical source of natural latex, latex is actually produced by numerous plants at varying quantities and levels of quality. In the 20s and 30s, Thomas Edison, Harvey Firestone, and Henry Ford became concerned about a potential shortage of rubber and began the research into alternatives. Ford commissioned a rubber plantation in South America modeled on an American town, and Edison tested thousands of plant species before settling on common goldenrod as an alternative source for the precious latex. At one point, even George Washington Carver consulted on the project. Edison bred gigantic goldenrod plants with superior latex content, and the Model T Edison owned rode on goldenrod-rubber tires. Eventually, for reasons I have yet to research in depth, the project slowed and the development of these high-latex goldenrod plants stopped.
During the war, the US discovered that a sagebrush-like plant near the Mexican border called guayule could be processed for rubber and they also developed synthetic rubber that could cover some, but not all, of the applications for which they so desperately needed natural rubber. Russia did similar research and developed a variety of dandelion which could supplement their needs for rubber. (The sticky white sap from a dandelion is a solution of latex and water.)
What these research projects effectively did, was try to find a more economical, easier to access rubber, one which the US could access with their current level of technology and the resources they currently had access to. The synthetic rubber requires massive chemical plants and access to oil wells, both of which are quite high-tech. But what interests me about the guayule and goldenrod research, is that they both lowered the level of technology someone in Utah needs to make rubber from scratch. They radically reduced the number of levels between a stone-age hunter-gatherer and a slingshot. This kind of research interests me. It is like a short-circuit, where the path of least resistance is suddenly shorter than it once was.
All of this history fascinates me. One day soon, I would like to put what I have learned into practice by making some rubber from scratch from plants available in my area, probably from dandelions unless I can find some guayule. I have some vague dreams of making the bands for a slingshot, and maybe even sending them to Joerg Sprave of the Slingshot Channel. That's the dream anyway.
In every problem, such as downing that squirrel on the branch, customize your solutions to the local situation. The more you know, the more opportunities you will be able to capitalize on. Such knowledge creates options and will allow you to choose the simplest and easiest ways to accomplish your goals.
Further Reading on Rubber and Rubber-Tree alternatives:
In Search of Thomas Edison’s Botanical Treasures – Science Talk Archive (nybg.org)
US2453858A - Process for obtaining rubber from goldenrod leaves - Google Patents
Natural rubber from dandelions (phys.org)