Alright, this was super ambitious; there are a number of simpler furnaces, ovens, and kilns we could be making before we reach this point; but I say fuck it, go for the gold. Let’s skip ahead.
We are going to attempt to build our own blast furnace for smelting ore. This is important. Smelting metal means making real tools. Real tools. No more chopping down trees with rocks. We’ll be able to build proper shelter, silverware, a police badge, an ice cream cone made of metal.
Obviously, you’re going to need some ore. Look for shiny veins running through rocks, if you’re specifically looking for iron, rust is a dead giveaway. As you find iron ore, you should pile it close to your fire. You want it to heat and cool a few times. Get an urn ready, and as the days progress, you’re going to use your hammerstone to crush the ore-stones into pebbles and store them in that urn.
There are a couple different kinds of furnaces we can make with the limited crap at our disposal.
The ideal design for our purposes is that of the Japanese Tatara furnace, still employed by swordsmiths in Japan. However, for our first try, we’ll aim lower.
Preparing to build and operate our bloomery is going to be a murderbitch. First, we’re going to need a shitload of clay. We’re also going to need a fuckton of charcoal. Also, we’re going to need bellows. So while your shitload of clay is settling, you’re going to have to either kill an animal, or become amazing at weaving. Also, you should be producing as much charcoal as possible
I don’t think we can get away with doing this without an illustration, but we’ll try anyway.
First we need to make a bed to build the furnace on. By this point you should have some broken pottery lying around; unless you’re a savant. You should also have some charcoal dust, if not, I’ll wait while you get some. Now crush your busted old pottery and mix it with the charcoal dust and ash. You’re going to pick a dry spot, make a patch of gravel about 5’x5′ and then make a 2’x’2 bed in the center out of your clay/charcoal mixture.
When that’s done, you’re going to get back to the pit and start firing bricks. You’re going to need enough bricks to make a two foot tall furnace thats got a footprint of about 1.5′ feet. Circular is better than square, but it’s also trickier, and you’re going to have to do some geometry to get the bricks the correct shape. An octagon might be a good compromise, but so far I haven’t found anything to support that guess. Now that we know how to make cement, we can reinforce the bloomery with concrete or make it out of stone rather than clay; either way the end result should be a 2 foot high chimney like structure with a window at ground level and a small 3″ diameter opening just less than a foot off the ground that we’re going to use as our air-hole. There’s probably a technical term for air-hole, but who cares.
Now the tricky part of making a blast furnace is the blast part. These things are all about keeping the fuel oxygenated, which means you have to make what’s called a tuyere, a pipe extending from your furnace that you’ll pump air into. Unfortunately, we cant make pipe just yet.
Since many of the future campsite crafting series will rely on this step; I’m afraid we’ll hit a paradox if we don’t assume the following will work.
In order to make a pipe to feed air into the furnace from the bellows, not to mention the bellows, we’re actually going to have to learn a few other survival tricks.
1. How to make glue
2. How to make cement
3. How to Tan Leather / Buckskin
4. How to make a needle
5. How to track an animal
6. How to set a wilderness trap
7. How to skin and treat an animal
Which will also require a slight mastery of
8. Improvised weapons of the wild
Now once you’ve learned all that (or found a pipe and bellows), we can finish building the furnace.
The Tuyere needs to be long enough to get you a safe distance from the furnace, but the longer it is the less efficient it will be. It can be made out of clay, but at this point I still have no idea how to hand-make a clay tuyere other than just my own guesswork. Stone tuyeres were found in ancient west african ruins. Copper and iron would be great, but unfortunately we need this bloomery up and running in order to get them.
I’m going to suggest for now that we can make a Tuyere by cementing around a bamboo stave and then coating it in clay; I have no idea if this will work, and it seems like it will crack as we use it; but if we can get it to work a couple of times, we’ll be able to get some pig iron to make some more sophisticated tools.
Let’s put a pin in that until someone with more expertise chimes in and get to work on those bellows.
Right now I’m opening this section up to suggestions, as I work on other sections, but I’ll continue to research this until it’s complete.