Now that we have covered the basic theoretical background of iron smelting, it is time we take a look at the more practical aspects of this wonderful madness. After all, this is what you came here for. Right?
Let us start with all the equipment which you will need.
The iron smelter’s tool chest is a fairly basic one, especially when compared to the varied range of specialised tooling used by most blacksmiths. You can do a lot with very little. I certainly always did.
Nevertheless, there are a few tools which are absolutely necessary for successful iron smelting, such as something to pump the air into the furnace, something to charge the ore, something to extract and compact the bloom, and so forth.
I will now do a quick overview of all the necessities. There will be some variation possible with all of them and different smelters might have their own preferences. Ultimately, your tooling will also be influenced by just how authentic you want to go with your smelting operation. How much measuring and documenting you might want to do will present another factor.
In other words: if you want to do this more authentically, then you will use a simpler kit, but you will also rely more on your senses and experience. Should you want to go down the more more modern scientific route, then you will quickly start accumulating various gadgets.
This post is a part of an instructional series on bloomery iron smelting. Should you have missed it, or should you want a refresher, then you might want to take a look at the previous installment:
PART I: Theory
It All Begins With a Place
Irregardless of your technological choices, you will need an appropriate place to build a bloomery furnace and run a smelt. Unlike a forge, this is not something that you can simply set up in a garage.
Ideally this should be done out in the open and away from any residential buildings. The initial phases of the smelt produce a lot of thick smoke, so this should be kept in mind and if you are going to be doing this in a backyard. You might need ask for permission or at least inform any neighbours, so that they do not end up hanging up their nice linen at the same time. Depending on your location and laws, you might also need to inform the local fire department, so that you do not end up with a large red truck on your drive-way.
Fire safety should generally be kept in mind when selecting a place, especially if you are going to be doing this on a dry Summer’s day. Therefore it smart to make sure that are no unnecessary flammable materials within at least 2-3 meters of the furnace. The jet of sparks, flames and hot gases escaping from the top of the furnace can also present some trouble, so make sure that there are no low-lying branches directly above the furnace. Nothing interrupts a smelt like a surprise firefighting operation.
At the same time, ideally you will want some kind of tarp or roof covering the space in front of the furnace, where you will be working. This is not strictly necessary and I have done without such luxuries on many an occasion, but the whole smelting operation takes at least 6 hours of non-stop work and being protected from the direct blaze of the sun or the unexpected spell of rain will make your life that much more bearable.
A note on electricity: Whether you will need access to electric power will depend entirely on your choice of tools. If you want to power your furnace with an electric blower then you will probably either need to drag out extension cords or bring a generator. Should you go down the low-tech route, then you do not need to bother with such things, which makes smelting in remote places that much easier. Another point in favour of hand-powered bellows if you ask me.
With all of that in mind, the tools of the bloomery operator can be divided into 3 groups, based on the 3 stages of the process: Preparation, Smelting & Bloom-Processing.
You will be using these tools to prepare the ore & charcoal, as well as to build the furnace:
Hatechet & Chopping Block
Hammer & Anvil-Stone
Hatchet & Chopping Block – You will be using this to split firewood, chop charcoal and possibly cut any organic fibbers which you will be adding to the clay mixture. Alternatively you may use a machete, or some other kind of chopping knife/cleaver to cut the charcoal & organics.
Hammer & Anvil-Stone – You will be using this to crush your iron ore once roasted. Alternatively, you may use a large metal mortar with a steel block welded onto a long rod as a pestle. With some of the crumblier bog ores, you can get away with just mashing them to gravel with a stout wooden stick.
Tarp – You will want something to catch the scatter when chopping the charcoal and crushing the ore. Having something on the ground when mixing the clay can also be helpful. This can take the form of a synthetic tarp, sackcloth, steel plate. Often I performed a lot of ore, fuel and clay preparation right in a wheelbarrow.
Digging Equipment – Some kind of mattock, pick or gardening hoe will come in handy if you need to clear the ground, dig a slag-pit, or just turn around the clay mixture.
Buckets – You will find these generally useful for holding ore, water, sand, clay, etc.
II. The Smelt
This covers the equipment needed on the long day when you attempt to smelt the ore:
Scoops & Ladles
Pointed Steel Rod & Hammer
Sledge-Hammer or Large Wooden Mallet
Wood Stump, Stone Slab or Large Anvil
Leather (Welder’s) Gloves
Patience & Endurance
- Notebook, Pen & Watch (Optional)
Bloom Axe (Optional)
A Few Bottles of Ale (Optional, yet Recommended)
Hatchet (again) – You will be using this to split firewood for the preheat.
Scoops & Ladles – You will need something to charge the ore. I like to use metal or wooden ladles of various sizes for the ore and a large scoop for the charcoal.
Wicker Basket for Charcoal – A large wicker basket with a pair of sturdy handles will make a quick job of shaking the dust out of your chopped charcoal. In a pinch I have also used plastic produce crates before.
Pokers – You will need to occasionally remove any obstructions to the airflow, such as droplets of slag solidifying in front of the tuyere. You can use a thin steel rod or simply a fresh wooden stick.
Pointed Steel Rod & Hammer – Used to break open the furnace door/wall and retrieve the bloom. Something along the lines of a 1.5-2 cm thick and 1+ m long mild steel rod with a point forged on will do the trick fine. Yes, you can use that piece of rebar that has been standing in corner for way too long.
Shovel – There can still be plenty of burning charcoal left in the furnace once you open it. You can easily move this to the side, along with any pieces of red hot furnace door, by scooping it all up with a metal shovel. An old fashioned wooden handle is good, just make sure that it does not have any plastic parts.
Bloom Tongs – You will need a pair of large tongs to grab the irregularly shaped bloom. They need to be able to grab something large and have long enough reigns so that you can put some distance in between yourself and the infernal heat. I like tongs with wide, curved, pince-like jaws with pointed tips for this, since they make it easy to grab irregular shapes.
Sledge Hammer or Huge Wooden Mallet – Once the bloom is out of the furnace, you will need to quickly knock off any large bits of slag and compact the bloom. This is done by hammering with a sledge-hammer or large wooden mallet.
Wood Stump, Stone Slab or Large Anvil – You will need to lay the fresh bloom on something in order to hammer it. A wood stump does the job well and after a smelt or two, the hot iron will burn a concavity into the wood, which helps contain the bloom as you compact it. Alternatively, a wide anvil-stone or large enough steel anvil will also do the job.
Water Bucket – Beyond the usual health & fire safety concerns, you might need to cool down some equipment.
Leather (Welder’s) Gloves – The bloomery is hot place and the smelting process involves handling white-hot metal. Some people like some extra protection in such situations.
Assistant – Smelting is a job for at least 2 people. So find yourself at least one more maniac. If you are using bellows, then one shall be pumping away while the other feeds the furnace. More helpers can make things even easier, since you can take turns on the bellows and somebody can perform tasks such as chopping additional charcoal while you smelt.
Should you end up using an electric blower, then you will still benefit from somebody helping you when it comes to opening the furnace and compacting the bloom. The whole process tending a furnace for hours on end also makes for an interesting social occasion.
Patience & Endurance – As already said, this will take a while.
Notebook, Pen & Watch – While not strictly necessary I would recommend keeping a smelting log where you write down the charges and the time in between the charges. This makes it very easy to monitor the smelt, and comes in handy when you when you want to figure out why a certain smelt failed.
Since in the beginning you probably be failing a few times and trying different things, keeping track of what you did is not the worst of ideas. On the other hand, the ancients did not dance around the furnace with a stopwatch, so if you want to explore this experiential aspect of ancient metallurgy, then you will have to find other solutions.
Bloom Axe (Optional) – Should you be smelting large blooms, let us say heavier than 3 kg, then you might want split the bloom with an axe to make subsequent reheating easier.
Scales (Optional) – Very useful if you want to be precise about how much ore and charcoal you are charging into the furnace. Makes it also possible to brag about how large a bloom you managed to smelt.
A Few Bottles of Ale (Optional) – It is a truth universally acknowledged, that a smelter slaving away in front of a furnace, must be in want of a beverage.
If you have read through the list so far, you must have noticed that I have been so far avoiding something.
It is the most important piece of equipment during the smelt. The one that makes it all possible and presents the difference between success and failure.
Yep, you are right. It is the air supply.
Bellows or Electric Blower – The Mighty Huff ‘n’ Puff Behind it All
You will need to pump a considerable amount of air into the furnace during the smelt, so that you can raise the temperature high enough. This air-blast will need to be pumped with some pressure behind it as well, so that it can light up the he whole bottom of the furnace and not just a small spot in front of the tuyere. This piece of equipment will also need to perform well for hours on end. Therefore some functional bellows or a good blower will be the one thing where you cannot make compromises.
In the past, most of my smelting failures were the result of using weak or faulty bellows.
When it comes to hand-cranked bellows there are several options available: accordion bellows, concertina bellows, drum bellows, pot bellows, piston bellows, box bellows, you name it. Provided that they are well made, they will all work. You may opt for a large single bellow or a pair of slightly smaller ones.
I have very little personal experience with using electric blowers, but there are plenty of smelters who have had great success with using them. I have seen everything from vacuum cleaners & leaf blowers to electric forge blowers being used for this purpose. Whatever blower you use, it means that you will need access to electricity where you smelt and that you will need to listen to the thing run for at least 6 hours. On the other hand, a mechanised blower reduce the amount of manpower needed to conduct a smelt.
It is easier to pump a large set of bellows or blower slower, than trying to push harder something that is a bit too weak.
Therefore when choosing or making bellows, think of something bigger than what you think you need. Then pick something even bigger. You will probably end up with something just big enough.
In my smelts, the minimum that I got away with was a single bellow where the air-chamber (lungs) roughly 70 cm long, 40 cm at the widest, and which opens to 50 cm in height. This was enough to produce workable blooms in smaller furnaces. Two such bellows would have made it easier to work with faster burn rates, thus opening more possibilities.
Once I have fine tuned a bellows design to the point where I am satisfied with it and it reasonable simple to follow, then I will also share it with you in fullest. Until then here are a few sketchbook drawings of my last bellows.
Some of my colleagues in the Czech Republic use very large single bellows, roughly based on illustrations in Agricola’s (1556) De Re Metallica. Using these results in a very laid-back sort of smelting, where you actually have to wait for a second or two in between the strokes of the bellows. The bellows are big enough so that they are opened by pulling on lever suspended from a tripod, while the air is then pushed out by the weight of a rock, sitting on top of the bellows.
In my report on the Smelting Week at University College Dublin, I was also writing about my attempts to make a smaller pair of bellows based on the Viking depiction of Sigurd the Dragonslayer and Regin the Smith. While these turned out to be a bit too small for smelting, they made a perfectly usable pair of forge bellows.
This in turn brings us to the last stage of the process and the last group of tools which you will need.
The whole smelting business is not over once you extract the bloom, for afterwards you still need to turn it into a usable iron ingot. This shall be done at the forge, by using the following:
Hammer (+ Sledge)
Let us take a more in depth look a these…
Forge – You will to reheat the bloom before you can further work it. For this you will need a forge which can easily get up to forge-welding temperatures.
A simple side-blown charcoal forge forge would be the most traditional option, and still my favourite. If you were smart enough to compact and possibly cut a large bloom as it came out of the furnace, then you shall not need a particularly large forge. So do not let any slag-fondling armchair archaeologist tell you that you need a bathtub sized forge for this.
I have found that a forge roughly 15 cm wide and 30 cm long serves 95% of my bloom-processing needs. What really matters is that the sides of the forge are steep enough, so that you may build a fire deep enough. You should aim for at least 15 cm of height above the tuyere.
With proper fire management, you can also get away with using a bottom-blast solid fuel forge. C0ntrary to some popular belief, you can even use coal, just make sure that you use a very clean fire.
What about that fancy gas forge that we like to use so much for pattern-welding?
Of course you can also use that, provided that it fits through the forge door. The ability to soak the bloom in that even welding heat does have its advantages. Just be warned that, at first, lot of slag leaks out of the bloom, which might make a mess of your forge lining. In the past I got around this to first do most of the compacting in a charcoal forge, and then switch to gas forge for any further work, such as fold-welding.
Anvil – Any anvil, which you use for forging, will do.
Tongs (Several) – You will need to securely hold the bloom while you work it. Since the bloom severely changes its shape and size in the process, you will do well to have a few different types and sizes of tongs.
Hammer (+Sledge) – Use your favourite (heavy) forging hammer. Should you be working with a striker, then naturally you will need a sledge-hammer as well.
Chisel/Hot Cut – You will need to cut the bloom with something once you start folding it.
Flux – At first, the bloom is self-fluxing with all the slag seeping out of it. Later you might need to add some flux to make the welding easier. Sand, crushed slag, glass, borax… Take your pick.
Water Bucket – A forge without one can be an annoying place to work in.
That is it.
This whole smelting business can be as simple or complicated as you want to make it. If you are going to be travelling to iron-smelting events, then it is best to learn how to do the most with as few tools as possible. After all, who actually enjoys dragging around half a workshop. Also the more things you have, the easier it is to forget something.
There while this list looks long, you probably already have most of these things. In practice they should all fit into the trunk of a normal car.
This concludes the 2nd part of this guide. The next episode will explain the basic raw materials needed, and how to process them. But until then, I have something to ask of you…
What about you?
Would you like to contribute to this guide by adding photos of your bellows, tools, furnaces or forges? Then you can send them to email@example.com. Should there be enough of a response, then I will be a dedicating a special post to reader’s contributions – showing off the different approaches possible.
Got any tips to share? What sort of tools do you use for your smelts? Write in the comments bellow!
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