If I had to choose one tool or piece of gear for survival, a knife would be on the top of my list. A knife can be used to make fires, shelters, weapons, traps, and most of the things needed for survival. With a few tools and some practice, anyone can have a workable knife (or chisel, hook, hinge, or any number of other tools and hardware) in a few hours of work. Besides the usefulness of the self-fashioned tool, it will bring a great amount of satisfaction and pride. The skill of blacksmithing will also put you in a very important position, should circumstances be reverted to post-civilization conditions. Your skill and handiwork will be in high demand.
Heating the Steel
Of first concern is having a way to heat the steel. There are various options. For fuel, the most common options are wood, coal, or propane. Wood is better in charcoal form, but it can be used as is. Its primary advantage is availability; you can pretty much find it anywhere, and it can easily be made into charcoal. Coal isn’t so easy to find, but if you have a source near you, it makes an excellent fuel. Propane would be the hardest to find in a survival situation, but there are many propane tanks and bottles around, and it might be a good option.
Charcoal can be made very easily. There are some excellent websites on building a charcoal retort– a simple arrangement using 55-gallon, steel drums. I personally use a very basic method. I buried half of a 55 gallon steel drum in the ground. I start a fire in it and load it with wood, even piling it up over the top. Through experience, I’ve learned to cover it at the appropriate time, which I will explain. After all of the wood has been burning sufficiently, I cover it with a piece of thin sheet metal. Then I seal the edges of the lid with some dirt. After twelve hours or more I uncover it, and if my timing was right everything is charcoal, with no unburnt wood and very little ash. I have a friend who takes the embers from his fireplace or wood stove, when he’s cleaning it out, and just douses them with water. Over time, he collects all the charcoal he needs this way. Indigenous peoples have perfected a method of covering a dry fallen log with dirt and lighting it on fire. Eventually, the entire log turns to charcoal. The key is to balance burning off the volatiles and cutting off the oxygen supply.
If you use wood or coal, you’ll want it in small chunks, golf ball-sized or smaller, especially with coal. As I mentioned earlier, wood is much more efficient as charcoal, but you can start the fire with wood and after much of it converts to charcoal, start working with your metal. I have done this before, and it can be a little challenging with all of the smoke and flames, but it does work. However, you must realize that just burning the charcoal or coal as a regular fire will not produce the needed temperatures to adequately heat up the steel for smithing. You’ll need some way to feed oxygen to the fire so it gets hot enough, using a device known as a bellows or blower. We’re going to assume there is no electricity available. There are instructions available online for making a bellows-style blower with leather and wood. There are also plans to make box blowers out of wood, and blowers with barrels and water. You can make blowers with whole animal skins. I even saw a video of African smiths using old cement sacks as their bellows, and they worked perfectly.
My favorite option is the hand crank cast iron blower that was once common across America, often associated with the Buffalo brand. These old blowers can be found on sites like eBay, but they are usually quite expensive since they are sought after items. With some patience and searching, they can be found at reasonable prices or even for free. First you have to know what you’re looking for. Go online and see what they look like. Then start keeping an eye out for them. Sometimes they’re decorating a yard or a store front. Sometimes, they can be found at yard sales or antique shops. There are many other possible places you might discover a blower, but make sure it isn’t completely frozen with rust, especially if you’re shelling out some money for it.
Once you get your hand crank blower, you’ll need to make yourself a forge. This can be done in various ways. The “Tim Lively forge” is popular. Basically, it’s a galvanized steel basin with a hole-filled, steel pipe air tube in the bottom. The basin is lined with adobe clay, leaving the holes in the air tube exposed in the bottom, and the blower is attached to the tube where it comes out of the forge. Do an Internet search on this, and you’ll see how simple it is. Other options are the brake drum forge or any simple forge one can weld together with scrap metal. Of course, if you’re going to weld together a forge, you would need to make it now, while electricity is available. The most primitive option is to just dig a small pit or make the forge walls with clay or adobe or even bricks or sheets of iron. Use a steel pipe for the air supply, coming in at the bottom of your forge, where the base of the fire will be, and attach your blower to the other end. This simple setup is common throughout third-world countries. The same forge can be used for both coal or charcoal.
I think it’s best to get set up for both coal/charcoal and propane. My propane setup is very basic, and it was both easy and fairly cheap to make. For a propane forge you’ll want an adjustable regulator. The regulators that come with barbecue grills are not adjustable and won’t work, at least not very well. I got mine at a plumbing supply store. I was also given some larger more industrial-sized ones with big dials on them, but I haven’t tried using them, and they’re just sitting in a box. The regulator is the most expensive item, but you’ll only need to buy it once, and it’s not really that expensive. With the regulator, get enough gas hose to go from your propane bottle to your forge, a few feet. Next is the burner itself. I did an Internet search, and there are a surprising number of different designs made out of cheap basic plumbing parts. I tried a couple and settled on one I liked. I’ll probably do more experimenting when I have time to try out some of the other styles. Make sure you look up plans for a Venturi-style burner and not the forced or blown air style, which requires a blower and electricity.
Building a Forge Body
You’ll also need a forge body. Mine is a large coffee can lined with ceramic wool. You can get ceramic wool at a pottery or ceramic supply store. You can cut it with scissors, but you should avoid breathing in the dust from it. Cut a piece that will fit around the inside of your coffee can, or whatever you’re using. While the ceramic wool is amazingly, completely fire- and heat-proof, it’s best to line the inside of the wool in your forge body with refractory cement, or even clay slip– a slurry made of clay and water. This will increase the durability of the forge, especially since you’ll be putting lots of metal in it. You’ll need a bracket of some sort to hold the burner in position, so it shoots its flame into the forge body. My setup is very simple, and I have the burner held to a simple frame with a hose clamp. While it does take some planning and work, it’s very satisfying to make and use a forge you made yourself.
Once you have your forge all set up and ready to go, it’s time to think about steel. In a survival or post-apocalyptic situation, excellent steel for knife and tool making should be readily available. I am constantly on the lookout for it and have amassed enough to last me well past my lifetime, but it’s always fun to try new and different types. Plus scavenging is just addictive, so I’m always on the lookout for more.
What you want to do is get in your mind the way steel is made and used. Steel for many structural applications is what’s called mild carbon steel. It only has a small amount of carbon added to it. Carbon, when added to iron, is what makes steel, and it is what gives it its ability to resist bending, as well as taking on and retaining hardness. When you think of a knife or tool edge, low carbon will take a sharp edge, but it won’t retain it when you start using it. High carbon will take an edge and then keep that edge for a long time.
There is a simple test you can perform as you start to learn the different types of steel. Take an old file and put it up to a running bench grinder. Make sure it’s sufficiently dark to see the sparks well. Observe the pattern of the sparks produced. They are complex and full of little fireworks-like bursts. That is an indication of high carbon. Now take a piece of angle iron or steel plumbing pipe and do the same. You’ll notice a much more simple spark pattern, with smaller and simpler fireworks bursts. That is due to its lack of carbon. A few common sources of high carbon steel are old tools, like lug wrenches, old files, car springs, saw blades, and even bed frames.
Forging and Quenching
With your source of heat ready and some steel collected, you’re ready to start forging. Try to avoid overheating the steel. Heat it up to a good bright cherry red to forge it. When you overheat it, the steel starts to shoot off little sparks and disintegrate. The part that is burning is losing its carbon content, and should just be scrapped at that point.
After you’ve shaped your implement, you can do some filing or sanding on it if you want to. It’s better to do it at this time rather than after you harden and temper it, because the steel is still in a softer state that is easier to work. If you want to do this, make sure you let the steel cool off gradually in the air rather than sticking it in a bucket of water to cool it off. Plunging it into water will harden it and may even crack it.
Now it’s time to harden and temper your tool, so it will take and hold a good edge. Stresses have been building up in the piece as you’ve been hammering it, so I like to heat it up in the forge to a dull red and then pull it out, letting it air cool until it’s black, doing this about three times. To harden the piece you’re going to heat it up to red hot and then plunge it into a quenchant, which will cool it off quickly and harden it. Water can be used, but you’ll have to experiment with it because it is such a severe quenchant that it will often crack your steel, ruining your work. The Japanese cover their knives and tools for quenching with a thin layer of watery clay, letting it dry, and then quenching in water. This is a better way to do it, but even then you may need to pull it back out before it completely cools. You would have to experiment, and they say that a soft water such as rain water is best.
A preferred quenchant is oil. This is much easier on the steel, because it cools it off more slowly. Various oils can be used, but each one cools the steel faster or slower, depending on the oil type and its make up. You want to cool the steel off as quickly as possible without cracking it. This results in the hardest state possible, which gives the best edge. A common oil that is also fairly fast is canola oil. That is what I use. It is best to warm up the oil first. I will heat up a railroad spike and put it in the oil to get it up to about 120 to 130 degrees Fahrenheit. In a survival situation, I imagine old motor oil would be readily available, and while not optimal it will definitely do the job.
Heat your piece of steel up to red hot. If you have a solid metal magnet, you can test the steel as it rises in temperature; you’ll know it’s ready when it loses its magnetism. You have to be careful when judging by colors. It’s best to do this in low lighting. If there is a lot of light, the piece will actually be much hotter than what the colors seem to indicate. Quenching the steel in a state that is too hot will result in satisfactory hardness but also large grain size. Steel is composed of grains, kind of like the grains of minerals in a rock, and you want as fine a grain as possible. Finer grain structure results in superior edge-holding potential. Higher heats in the forge result in larger grain structure, which is bad for edge holding.
This might be getting a bit complicated, but it’s not that big a deal. If you just jump in and start smithing, you will learn as you go. Even an inferior quality knife or tool is far better than something made from copper or bronze, which was being used at one time to keep civilizations going.
Quench your piece, going quickly from the forge to the quenching fluid. Hold it in there for about thirty seconds and then pull it out. Next comes tempering. The steel is in a very unstable and fragile state right now. It’s glass-like and too hard to be of practical use. If you were to drop it on a hard surface, it would shatter. That is why you need to temper it. Tempering is accomplished at about 400 degrees Fahrenheit. Fortunately, steel produces different oxidizing colors, as it rises in temperature. Probably a good way to do this at first is to have a scrap chunk of steel that you have heated up in the forge; use something heavier with some heat-holding ability. Take your piece that you have just quenched and hardened and, using some sandpaper or a sharpening stone or anything sufficiently abrasive, shine one side of it. This can be done quickly and doesn’t have to be pretty or perfect. You just need to see some steel surface.
Pull out the scrap chunk of steel you heated up in the forge and lay your piece against it. Try to just put the thickest part, like the spine of a knife blade, against the hot steel, letting the edge hang off, pointing away from the hot steel. Keep a close eye on the shiny part. Before too long you will see some light yellow color creeping across the surface. If you were to leave this, it would eventually turn a darker yellow, then brown, then purple, then dark, blue, light blue, and finally gray blue. Ideally, you want the edge to be a dark yellow to brown color. Move the piece around so the color you want is as evenly spread as possible along the edge. For instance, if the yellow starts to darken faster toward the point of a blade you are tempering, move the point farther away from the source of tempering heat to slow down the tempering process in that area. You may have to reheat the scrap piece you are using as a heat source. Take it slowly, especially as you are learning.
Tempering can be done directly in the fire of the forge, but this requires experience. In a non-survival situation, I use an oven, so I can make sure I have a consistent and measurable heat. When you actually use the knife or tool, you will be able to tell whether you tempered it enough or not. If it chips and breaks in use, you didn’t temper it enough. If it get dull easily, you tempered it too much.
Now your piece is ready to be finished. You can sand it, or do whatever else you want to achieve a desirable appearance. Mount a handle on the tang, put the final edge on it, and you’re ready to use it.