Quotulatiousness

November 24, 2024

QotD: Wood

Filed under: Quotations, Technology, Woodworking — Tags: , , — Nicholas @ 01:00

If someone today invented wood, it would never be approved as a building material. It burns, it rots, it has different strength properties depending on its orientation, no two pieces are alike, and most cruelly of all, it expands and contracts based on the relative humidity around it. However, despite all of these problems, wood is the material of choice when building houses. In fact, we can use wood better than we can use steel, masonry and concrete.

Joseph Lstiburek, Builder’s Guide to Cold Climates, 2000.

August 29, 2024

How to Make a Ladle | Episode 1

Filed under: Tools, Woodworking — Tags: , , — Nicholas @ 02:00

Paul Sellers
Published Apr 26, 2024

It may not be a large project, but creating a ladle from fully kiln-dried hardwoods like sycamore and maple differs from green, uncured wood. Tougher to carve yes, but there is no shrinkage and no risk of cracking through drying. It is a wonderful project for learning to work with multi-directional grain and to also use gouges and such.

This is a great beginner guide for those starting with gouge work.
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August 23, 2024

How to bind loose pages together: a simple method

Filed under: Books, Tools — Tags: — Nicholas @ 02:00

Annesi Bindings
Published Mar 7, 2021

This video demonstrates a very simple way of binding loose pages together. It is intended for people who have texts that they want to bind together, but who are looking for a better method than simply stapling, paper clips, or ring binding. The video is suitable for non-bookbinders and only requires minimal materials and PVA glue.

If you are looking for how to bind loose pages into a hardcover book, I demonstrate that in this video:
How to Bind a Perfect-bound Book

August 17, 2024

QotD: Sheep and wool in the ancient and medieval world

Filed under: Europe, History, Quotations — Tags: , , , , , , — Nicholas @ 01:00

Our second fiber, wool, as readers may already be aware, comes from sheep (although goat and horse-hair were used rarely for some applications; we’re going to stick to sheep’s wool here). The coat of a sheep (its fleece) has three kinds of fibers in it: wool, kemp and medullated fibers. Kemp fibers are fairly weak and brittle and won’t accept dye and so are generally undesirable, although some amount of kemp may end up in wool yarn. Likewise, medullated fibers are essentially hair (rather than wool) and lack elasticity. But the wool itself, composed mostly of the protein keratin along with some lipids, is crimped (meaning the fibers are not straight but very bendy, which is very valuable for making fine yarns) and it is also elastic. There are reasons for certain applications to want to leave some of the kemp in a wool yarn that we’ll get to later, but for the most part it is the actual wool fibers that are desirable.

Sheep themselves probably descend from the wild mouflon (Ovis orientalis) native to a belt of uplands bending over the northern edge of the fertile crescent from eastern Turkey through Armenia and Azerbaijan to Iran. The fleeces of these early sheep would have been mostly hair and kemp rather than wool, but by the 4th millennium BC (as early as c. 3700 BC), we see substantial evidence that selective breeding for more wool and thicker coats has begun to produce sheep as we know them. Domestication of course will have taken place quite a bit earlier (selective breeding is slow to produce such changes), perhaps around 10,000 BC in Mesopotamia, spreading to the Indus river valley by 7,000 BC and to southern France by 6,000 BC, while the replacement of many hair breeds of sheep with woolly sheep selectively bred for wool production in Northern Mesopotamia dates to the third century BC.1 That process of selective breeding has produced a wide variety of local breeds of sheep, which can vary based on the sort of wool they produce, but also fitness for local topography and conditions.

As we’ve already seen in our discussion on Steppe logistics, sheep are incredibly useful animals to raise as a herd of sheep can produce meat, milk, wool, hides and (in places where trees are scarce) dung for fuel. They also only require grass to survive and reproduce quickly; sheep gestate for just five months and then reach sexual maturity in just six months, allowing herds of sheep to reproduce to fill a pasture quickly, which is important especially if the intent is not merely to raise the sheep for wool but also for meat and hides. Since we’ve already been over the role that sheep fill in a nomadic, Eurasian context, I am instead going to focus on how sheep are raised in the agrarian context.

While it is possible to raise sheep via ranching (that is, by keeping them on a very large farm with enough pastureland to support them in that one expansive location) and indeed sheep are raised this way today (mostly in the Americas), this isn’t the dominant model for raising sheep in the pre-modern world or even in the modern world. Pre-modern societies generally operated under conditions where good farmland was scarce, so flat expanses of fertile land were likely to already be in use for traditional agriculture and thus unavailable for expansive ranching (though there does seem to be some exception to this in Britain in the late 1300s after the Black Death; the sudden increase in the cost of labor – due to so many of the laborers dying – seems to have incentivized turning farmland over to pasture since raising sheep was more labor efficient even if it was less land efficient and there was suddenly a shortage of labor and a surplus of land). Instead, for reasons we’ve already discussed, pastoralism tends to get pushed out of the best farmland and the areas nearest to towns by more intensive uses of the land like agriculture and horticulture, leaving most of the raising and herding of sheep to be done in the rougher more marginal lands, often in upland regions too rugged for farming but with enough grass to grow. The most common subsistence strategy for using this land is called transhumance.

Transhumant pastoralists are not “true” nomads; they maintain permanent dwellings. However, as the seasons change, the transhumant pastoralists will herd their flocks seasonally between different fixed pastures (typically a summer pasture and a winter pasture). Transhumance can be either vertical (going up or down hills or mountains) or horizontal (pastures at the same altitude are shifted between, to avoid exhausting the grass and sometimes to bring the herds closer to key markets at the appropriate time). In the settled, agrarian zone, vertical transhumance seems to be the most common by far, so that’s what we’re going to focus on, though much of what we’re going to talk about here is also applicable to systems of horizontal transhumance. This strategy could be practiced both over relatively short distances (often with relatively smaller flocks) and over large areas with significant transits (see the maps in this section; often very significant transits) between pastures; my impression is that the latter tends to also involve larger flocks and more workers in the operation. It generally seems to be the case that wool production tended towards the larger scale transhumance. The great advantage of this system is that it allows for disparate marginal (for agriculture) lands to be productively used to raise livestock.

This pattern of transhumant pastoralism has been dominant for a long time – long enough to leave permanent imprints on language. For instance, the Alps got that name from the Old High German alpa, alba meaning which indicated a mountain pasturage. And I should note that the success of this model of pastoralism is clearly conveyed by its durability; transhumant pastoralism is still practiced all over the world today, often in much the same way as it was centuries or millennia ago, with a dash of modern technology to make it a bit easier. That thought may seem strange to many Americans (for whom transhumance tends to seem very odd) but probably much less strange to readers almost anywhere else (including Europe) who may well have observed the continuing cycles of transhumant pastoralism (now often accomplished by moving the flocks by rail or truck rather than on the hoof) in their own countries.

For these pastoralists, home is a permanent dwelling, typically in a village in the valley or low-land area at the foot of the higher ground. That low-land will generally be where the winter pastures are. During the summer season, some of the shepherds – it does not generally require all of them as herds can be moved and watched with relatively few people – will drive the flocks of sheep up to the higher pastures, while the bulk of the population remains in the village below. This process of moving the sheep (or any livestock) over fairly long distances is called droving and such livestock is said to be moved “on the hoof” (assuming it isn’t, as in the modern world, transported by truck or rail). Sheep are fairly docile animals which herd together naturally and so a skilled drover can keep large flock of sheep together on their own, sometimes with the assistance of dogs bred and trained for the purpose, but just as frequently not. While cattle droving, especially in the United States, is often done from horseback, sheep and goats are generally moved with the drovers on foot.

Bret Devereaux, “Collections: Clothing, How Did They Make It? Part I: High Fiber”, A Collection of Unmitigated Pedantry, 2021-03-05.


    1. On this, note E. Vila and D. Helmer, “The Expansion of Sheep Herding and the Development of Wool Production in the Ancient Near East” in Wool Economy in the Ancient Near East and the Aegean, eds. C. Breniquet and C. Michel (2014), which has the archaeozoological data).

August 9, 2024

Why Oil Paint Is So Expensive | So Expensive

Filed under: Economics, History, Media — Tags: , , , — Nicholas @ 02:00

Business Insider
Published Jul 13, 2019

Oil paint is simple. At its most basic, it’s just a mixture of oil and pigment. But depending on the color and quality, a liter of this paint could cost you $285 to $1,100.

While the rise of oil paint is associated with the Renaissance, paintings using poppy-seed oil have been dated as far back as seventh-century Afghanistan. So what is it that makes this paint so special? And why is it so expensive?
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August 3, 2024

The Rise, Fall, And Revival Of Art Deco | A Style Is Born W/ @KazRowe

Filed under: Architecture, France, History, Technology, USA — Tags: , , , , , , — Nicholas @ 02:00

Wayfair
Published Jun 15, 2023

Welcome to A Style is Born, hosted by YouTuber, cartoonist, and champion of under-represented history, Kaz Rowe!

Join us as we go down the rabbit hole and uncover the unique histories and origin stories behind your favorite design styles. In this first episode of Season 2, we delve into the history-rich Art Deco movement.

Chapters
Intro – 00:00
History – 00:45
Influences, Elements, & Materials – 04:58
1980s Art Deco Revival Via Memphis Group – 07:46
Conclusion – 09:13
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May 11, 2024

Blacksmithing Basics for Woodworkers: Launching Your First Forging Project

Filed under: Tools — Tags: , , , — Nicholas @ 02:00

Rex Krueger
Published Jan 31, 2024

What to expect your first night at a blacksmithing club.

Project plans: rexkrueger.com/store
Patrons saw this video early: patreon.com/rexkrueger

Abana National Organization: https://abana.org/
My review of 2 affordable hammers: https://www.youtube.com/watch?v=q0mGz…
I Forge Iron Forum: https://www.iforgeiron.com/

May 9, 2024

“The ability to believe entire gargling nonsense is strong in the [environmental] sector – as with this particular claim that we’re going to run out of rock”

Filed under: Britain, Economics, Environment — Tags: , , , , — Nicholas @ 05:00

Tim Worstall really, really enjoys kicking the stuffing out of strawman arguments, especially when they touch on something he’s very well informed about:

Some environmental claims are not just perfectly valid they’re essential for the continuation of life at any level above E. Coli. None of us would want the Thames to return to the state of 1950 when there was nothing living in it other than a collection of that E. Coli reflecting the interesting genetic and origin mix of the population of London. Sure, the arguments from Feargal and the like that a river running through 8 million people must be clean enough to swim in at all times is a bit extreme the other way around. One recent estimate has it that to perform that task for England would cost £260 billion — a few swimming baths sounds like a more sensible use of resources than getting all the rivers sparkling all the time.

Some are more arguable — violent and immediate climate change would be a bad idea, losing Lowestoft below the waves (possibly Dartford too) in 2500 AD might be something we can all live with. Arguable perhaps.

But some of these claims are wholly and entirely doolally. So much so that it’s difficult to imagine that grown adults take them seriously. But, sadly, they do and they do so on our money too.

An example:

    Wow. According to this research 40% of the 1.5C C02 budget could be used just for digital & internet use/infrastructure & 55% of the earths carrying capacity for minerals & metals for the same use.

The internet alone could use 55% of the Earth’s carrying capacity of metals and minerals? Well, to take that seriously is insane. That is not mere hyperbolic insult, that actually is insane. I write as someone who has written an entire book on this very subject (available here, for free, save your money to buy a subscription to this excellent Substack instead). There is no metal or mineral that we’re even going to run short of — in the technical, not economic, sense that is — for tens of millions of years yet. As the average lifetime of a species is perhaps 2 million years that should see us out.

So, clearly, they’re using some odd definition of how many minerals and metals we’ve got that we can use. I thought they’d do the usual Club of Rome thing (no, read the book to find out), confuse mineral reserves with what’s available and thus insist we all died last Tuesday afternoon. Rather to my surprise, no, they didn’t. They went further into raging lunacy.

It’s not wholly obvious as they don’t really quite announce their assumption, it’s necessary to track back a bit — and that’s a problem in itself. A top tip about scientific papers — if they say “As Bloggs said” then what that really means is that many people accept what Bloggs said as being true and also useful. You do not have to reprove Einstein every time you do physics, you can just say “As is known”. You’ve only got to reprove Al if that’s what you’re really trying to do.

Thus, if a definition is a referral back to something else, elsewhere, then you can be sure that the definition is a building block being used by others in their own papers. It’s a generalised insanity, not a specific one.

So, what is that limit?

    Here we quantify the environmental impacts of digital content consumption encompassing all the necessary infrastructure linked to the consumption patterns of an average user. By applying the standardised life cycle assessment (LCA) methodology, we evaluate these impacts in relation to the per capita share of the Earth’s carrying capacity using 16 indicators related to climate change, nutrients flows, air pollution, toxicity, and resources use, for which explicit thresholds that should never be exceeded were defined

Now this is in Nature Communications. So it’s science. Even, it’s Science. It’s also lunatic. For, tracking back to try to find what those “resources use” are that will be 55% used up by the internet. It’s possible to think that maybe we’re going to use too much germanium in the glass in the fibreoptic cables say, or erbium in the repeaters, or … specific elements might be in short supply? As the book wot I wrote above points out, that’s nonsense. So, what is the claim?

Tracking back we get to this:

    Resource use, mineral and metals MRD kg Sb eq Abiotic resource depletion (ADP ultimate reserves) 2.19E+08 3.18E-02 JRC calculation based on factor 2 concept Bringezu (2015); Buczko et al. (2016) Resource use

That’s from Table 3.

Which takes us one stage further back. This paper here is talking about Planetary Boundaries and as with the building block idea. PBs — I assume — make the assumption that Bringzeu, and Biczlo et al have given us a useful guide to what those PBs are. Which is why they just use their method, not invent a new one. But that, in turn, also means that other people working on PBs are likely to be using that same definition.

[…]

Note what they’re doing. Humans should not take out of that environment more than nature puts back into it each year. That’s some pretty dumb thinking there, as we don’t, when we use a metal or mineral — except in very rare circumstances — take it off planet. We move it around a bit, no more. But the claim really is that we should abstract, for use, no more than is naturally added back each year.

So, the correct limitation on our minerals use is how much magma volcanoes add each year.

No, really, humanity can use no more earth than gets thrown out of a volcano each year. That’s it. To use more would mean that we are depleting the stock and that’s not sustainable, see?

January 31, 2024

Don’t RUIN your workbench with 2x4s (use these tips instead)

Filed under: Tools, Woodworking — Tags: , , , — Nicholas @ 02:00

Rex Krueger
Published 8 Nov 2023
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January 11, 2024

Art Deco Architecture

Filed under: Architecture, History, USA — Tags: , , , , , , , — Nicholas @ 02:00

Prof. Lynne Porter
Published 22 Apr 2021

Lecture for Fairfield University class called “What We Leave Behind: the History of Fashion & Decor”.

January 3, 2024

QotD: Iron and steel

Filed under: History, Quotations, Science, Technology — Tags: , , , , , — Nicholas @ 01:00

I don’t want to get too bogged down in the exact chemistry of how the introduction of carbon changes the metallic matrix of the iron; you are welcome to read about it. As the carbon content of the iron increases, the iron’s basic characteristics – its ductility and hardness (among others) – changes. Pure iron, when it takes a heavy impact, tends to deform (bend) to absorb that impact (it is ductile and soft). Increasing the carbon-content makes the iron harder, causing it to both resist bending more and also to hold an edge better (hardness is the key characteristic for holding an edge through use). In the right amount, the steel is springy, bending to absorb impacts but rapidly returning to its original shape. But too much carbon and the steel becomes too hard and not ductile enough, causing it to become brittle.

Compared to the other materials available for tools and weapons, high carbon “spring steel” was essentially the super-material of the pre-modern world. High carbon steel is dramatically harder than iron, such that a good steel blade will bite – often surprisingly deeply – into an iron blade without much damage to itself. Moreover, good steel can take fairly high energy impacts and simply bend to absorb the energy before springing back into its original shape (rather than, as with iron, having plastic deformation, where it bends, but doesn’t bend back – which is still better than breaking, but not much). And for armor, you may recall from our previous look at arrow penetration, a steel plate’s ability to resist puncture is much higher than the same plate made of iron (bronze, by the by, performs about as well as iron, assuming both are work hardened). of course, different applications still prefer different carbon contents; armor, for instance, tended to benefit from somewhat lower carbon content than a sword blade.

It is sometimes contended that the ancients did not know the difference between iron and steel. This is mostly a philological argument based on the infrequency of a technical distinction between the two in ancient languages. Latin authors will frequently use ferrum (iron) to mean both iron and steel; Greek will use σίδηρος (sideros, “iron”) much the same way. The problem here is that high literature in the ancient world – which is almost all of the literature we have – has a strong aversion to technical terms in general; it would do no good for an elite writer to display knowledge more becoming to a tradesman than a senator. That said in a handful of spots, Latin authors use chalybs (from the Greek χάλυψ) to mean steel, as distinct from iron.

More to the point, while our elite authors – who are, at most dilettantish observers of metallurgy, never active participants – may or may not know the difference, ancient artisans clearly did. As Tylecote (op. cit.) notes, we see surface carburization on tools as clearly as 1000 B.C. in the Levant and Egypt, although the extent of its use and intentionality is hard to gauge to due rust and damage. There is no such problem with Gallic metallurgy from at least the La Tène period (450 BCE – 50 B.C.) or Roman metallurgy from c. 200 B.C., because we see evidence of smiths quite deliberately varying carbon content over the different parts of sword-blades (more carbon in the edges, less in the core) through pattern welding, which itself can leave a tell-tale “streaky” appearance to the blade (these streaks can be faked, but there’s little point in faking them if they are not already understood to signify a better weapon). There can be little doubt that the smith who welds a steel edge to an iron core to make a sword blade understands that there is something different about that edge (especially since he cannot, as we can, precisely test the hardness of the two every time – he must know a method that generally produces harder metal and be working from that assumption; high carbon steel, properly produced, can be much harder than iron, as we’ll see).

That said, our ancient – or even medieval – smiths do not understand the chemistry of all of this, of course. Understanding the effects of carbuzation and how to harness that to make better tools must have been something learned through experience and experimentation, not from theoretical knowledge – a thing passed from master to apprentice, with only slight modification in each generation (though it is equally clear that techniques could move quite quickly over cultural boundaries, since smiths with an inferior technique need only imitate a superior one).

Bret Devereaux, “Collections: Iron, How Did They Make It, Part IVa: Steel Yourself”, A Collection of Unmitigated Pedantry, 2020-10-09.

November 15, 2023

“If you cannot make your own pig iron, you are just LARP’n as a real power”

Filed under: Britain, History, Technology — Tags: , , , , — Nicholas @ 04:00

CDR Salamander talks about the importance of an old industry to a modern industrial economy:

We probably need to start this out by explaining exactly what a blast furnace is and why it is important if you want to be a sovereign nation.

First of all, what it does;

    The purpose of blast furnace is to chemically reduce and physically convert iron oxide into liquid iron called “hot metal” The blast furnace is a huge, steel stack lined with refractory brick where iron ore, coke and limestone are charged into the top and preheated air is blown into the bottom. The raw materials require 6 to 8 hours to descend to the bottom of the furnace where they become the final product of liquid slag and liquid iron. These liquid products are drained from the furnace at regular intervals. The hot air that was blown into the bottom of the surface ascends to the top in 6 to 8 seconds after going through numerous chemical reactions. Once the blast furnace is started it continuously runs for four to ten years with only short stops to perform planned maintenance.

Why are blast furnaces so important? Remember the middle part of Billy Joel’s “Iron, coke, chromium steel?”

“Coke” is in essence purified coal, almost pure carbon. It is about the only thing that can at scale make “new” or raw iron, aka “pig iron”. Only coke in a blast furnace can make enough heat to turn iron ore in to iron. You can’t get that heat with an electric furnace.

Pig iron is the foundation of everything that follows that makes an industrial power. If you cannot make your own pig iron, you are just LARP’n as a real power.

It takes a semester at least to understand this, but here is all you really need to know;

    Primary differences

    While the end product from each of these is comparable, there are clearly differences between their capabilities and process. Comparing each type of furnace, the major distinctions are:

    Material source – blast furnaces can melt raw iron ore as well as recycled metal, while electric arc furnaces only melt recycled or scrap metal.

    Power supply – blast furnaces primarily use coke to supply the energy needed to heat up the metal, while EAFs use electricity to accomplish this.

    Environmental impact – because of the fuels used for each, EAFs can produce up to 85% less carbon dioxide than blast furnaces.

    Cost – EAFs cost less than blast furnaces and take up less space in a factory.

    Efficiency – EAFs also reach higher temperatures much faster and can melt and produce products more quickly, as well as having more precise control over the temperature compared to blast furnaces.

We’ll get to that environmental impact later, but the “Material source” section is your money quote.

Without a blast furnace, all you can do is recycle scrap iron.

You cannot fight wars at scale if all you have is scrap iron. You cannot be an industrial hub off of just scrap iron. If you are a nation of any size, you then become economically and security vulnerable at an existential level. I don’t care how much science fiction you get nakid and roll in; wars are won by steel, ungodly amounts of steel.

Where do you get the steel to build your warships? Your tanks? Your factories? Your buildings? Your factories?

If you can only use scrap, then you are simply a scavenger living off the hard work of previous generations. Eventually you run out. You will wind up like the cypress mills of old Florida where, once they ran out of cypress trees, they simply sold off the cypress lumber their mills were constructed of … and then went bankrupt.

October 26, 2023

QotD: Making steel

Filed under: History, Quotations, Science, Technology — Tags: , , — Nicholas @ 01:00

Let’s start with the absolute basics: what is steel? Fundamentally, steel is an alloy of iron and carbon. We can, for the most part, dispense with many modern varieties of steel that involve more complex alloys; things like stainless steel (which add chromium to the mix) were unknown to pre-modern smiths and produced only by accident. Natural alloys of this sort (particularly with manganese) might have been produced by accident where local ores had trace amounts of other metals. This may have led to the common belief among ancient and medieval writers that iron from certain areas was superior to others (steel from Noricum in the Roman period, for instance, had this reputation, note Buchwald, op. cit. for the evidence of this), though I have not seen this proved with chemical studies.

So we are going to limit ourselves here to just carbon and iron. Now in video-game logic, that means you take one “unit” of carbon and one “unit” of iron and bash them together in a fire to make steel. As we’ll see, the process is at least moderately more complicated than that. But more to the point: those proportions are totally wrong. Steel is a combination of iron and carbon, but not equal parts or anything close to it. Instead, the general division goes this way (there are several classification systems but they all have the same general grades):

Below 0.05% carbon or so, we just refer to that as iron. There is going to be some small amount of carbon in most iron objects, picked up in the smelting or forging process.
From 0.05% carbon to 0.25% carbon is mild or low carbon steel.
From about 0.3% to about 0.6%, we might call medium carbon steel, although I see this classification only infrequently.
From 0.6% to around 1.25% carbon is high-carbon steel, also known as spring steel. For most armor, weapons and tools, this is the “good stuff” (but see below on pattern welding).
From 1.25% to 2% are “ultra-high-carbon steels” which, as far as I can tell didn’t see much use in the ancient or medieval world.
Above 2%, you have cast iron or pig iron; excessive carbon makes the steel much too hard and brittle, making it unsuitable for most purposes.

Bret Devereaux, “Collections: Iron, How Did They Make It, Part IVa: Steel Yourself”, A Collection of Unmitigated Pedantry, 2020-10-09.

October 10, 2023

QotD: The production of charcoal in pre-industrial societies

Filed under: Europe, History, Quotations, Technology — Tags: , , , , — Nicholas @ 01:00

Wood, even when dried, contains quite a bit of water and volatile compounds; the former slows the rate of combustion and absorbs the energy, while the latter combusts incompletely, throwing off soot and smoke which contains carbon which would burn, if it had still been in the fire. All of that limits the burning temperature of wood; common woods often burn at most around 800-900°C, which isn’t enough for the tasks we are going to put it to.

Charcoaling solves this problem. By heating the wood in conditions where there isn’t enough air for it to actually ignite and burn, the water is all boiled off and the remaining solid material reduced to lumps of pure carbon, which will burn much hotter (in excess of 1,150°C, which is the target for a bloomery). Moreover, as more or less pure carbon lumps, the charcoal doesn’t have bunches of impurities which might foul our iron (like the sulfur common in mineral coal).

That said, this is a tricky process. The wood needs to be heated around 300-350°C, well above its ignition temperature, but mostly kept from actually burning by lack of oxygen (if you let oxygen in, the wood is going to burn away all of its carbon to CO2, which will, among other things, cause you to miss your emissions target and also remove all of the carbon you need to actually have charcoal), which in practice means the pile needs some oxygen to maintain enough combustion to keep the heat correct, but not so much that it bursts into flame, nor so little that it is totally extinguished. The method for doing this changed little from the ancient world to the medieval period; the systems described by Pliny (NH 16.8.23) and Theophrastus (HP 5.9.4) is the same method we see used in the early modern period.

First, the wood is cut and sawn into logs of fairly moderate size. Branches are removed; the logs need to be straight and smooth because they need to be packed very densely. They are then assembled into a conical pile, with a hollow center shaft; the pile is sometimes dug down into the ground, sometimes assembled at ground-level (as a fun quirk of the ancient evidence, the Latin-language sources generally think of above-ground charcoaling, whereas the Greek-language sources tend to assume a shallow pit is used). The wood pile is then covered in a clay structure referred to a charcoal kiln; this is not a permanent structure, but is instead reconstructed for each charcoal burning. Finally, the hollow center is filled with brushwood or wood-chips to provide the fuel for the actual combustion; this fuel is lit and the shaft almost entirely sealed by an air-tight layer of earth.

The fuel ignites and begins consuming the oxygen from the interior of the kiln, both heating the wood but also stealing the oxygen the wood needs to combust itself. The charcoal burner (often called collier, before that term meant “coal miner” it meant “charcoal burner”) manages the charcoal pile through the process by watching the smoke it emits and using its color to gauge the level of combustion (dark, sooty smoke would indicate that the process wasn’t yet done, while white smoke meant that the combustion was now happening “clean” indicating that the carbonization was finished). The burner can then influence the process by either puncturing or sealing holes in the kiln to increase or decrease airflow, working to achieve a balance where there is just enough oxygen to keep the fuel burning, but not enough that the wood catches fire in earnest. A decent sized kiln typically took about six to eight days to complete the carbonization process. Once it cooled, the kiln could be broken open and the pile of effectively pure carbon extracted.

Raw charcoal generally has to be made fairly close to the point of use, because the mass of carbon is so friable that it is difficult to transport it very far. Modern charcoal (like the cooking charcoal one may get for a grill) is pressed into briquettes using binders, originally using wet clay and later tar or pitch, to make compact, non-friable bricks. This kind of packing seems to have originated with coal-mining; I can find no evidence of its use in the ancient or medieval period with charcoal. As a result, smelting operations, which require truly prodigious amounts of charcoal, had to take place near supplies of wood; Sim and Ridge (op cit.) note that transport beyond 5-6km would degrade the charcoal so badly as to make it worthless; distances below 4km seem to have been more typical. Moving the pre-burned wood was also undesirable because so much material was lost in the charcoaling process, making moving green wood grossly inefficient. Consequently, for instance, we know that when Roman iron-working operations on Elba exhausted the wood supplies there, the iron ore was moved by ship to Populonia, on the coast of Italy to be smelted closer to the wood supply.

It is worth getting a sense of the overall efficiency of this process. Modern charcoaling is more efficient and can often get yields (that is, the mass of the charcoal when compared to the mass of the wood) as high as 40%, but ancient and medieval charcoaling was far less efficient. Sim and Ridge (op cit.) note ratios of initial-mass to the final charcoal ranging from 4:1 to 12:1 (or 25% to 8.3% efficiency), with 7:1 being a typical average (14%).

We can actually get a sense of the labor intensity of this job. Sim and Ridge (op cit.) note that a skilled wood-cutter can cut about a cord of wood in a day, in optimal conditions; a cord is a volume measure, but most woods mass around 4,000lbs (1,814kg) per cord. Constructing the kiln and moving the wood is also likely to take time and while more than one charcoal kiln can be running at once, the operator has to stay with them (and thus cannot be cutting any wood, though a larger operation with multiple assistants might). A single-man operation thus might need 8-10 days to charcoal a cord of wood, which would in turn produce something like 560lbs (253.96kg) of charcoal. A larger operation which has both dedicated wood-cutters and colliers running multiple kilns might be able to cut the man-days-per-cord down to something like 3 or 4, potentially doubling or tripling output (but requiring a number more workers). In short, by and large our sources suggest this was a fairly labor intensive job in order to produce sufficient amounts of charcoal for iron production of any scale.

Bret Devereaux, “Iron, How Did They Make It? Part II, Trees for Blooms”, A Collection of Unmitigated Pedantry, 2020-09-25.

September 14, 2023

I Built a FOOT POWERED Lathe (Most requested video)

Filed under: Tools, Woodworking — Tags: , , , — Nicholas @ 04:00

Rex Krueger
Published 13 Sep 2023

How to make a hand tool spring pole lathe. Almost.
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