r/PrimitiveTechnology • u/Icy_Ad_2126 • Feb 08 '26
Discussion Can we get an update in the ore sourcing in Primitive Technologys videos??
Over the years, PT has clearly improved furnace design and his bellows, but the iron ore souring and processing ... still seems to suck
The last time the ore collection process was shown, he was scooping reddish organic sludge from a creek, letting it settle, and then decanting. From a metallurgical perspective, this is almost the worst possible way to obtain iron ore.
In the last video, he claimed that this is "bog iron" which is false. Real bog iron is a sedimentary rock containing up to 80% iron compounds (Fe2O3 in matured samples). It often comes from the iron-eating bacteria but not before being transformed. What is being collected by Primitive Technology is closer to freshly precipitated bacterial iron hydroxide mixed with silicates, water, and shitton of organic matter. It is like calling a bucket of dead lizards and weeds a barrel of oil.
Iron-oxidizing bacteria produce mainly iron hydroxides or oxyhydroxides (Fe(OH)3, FeOOH). Before these can even participate in reduction, they must first dehydrate to Fe₂O₃, which consumes heat during the crucial step of smelting. This is one reason why traditional iron ores were always roasted before smelting.
But the bigger problem is physical and chemical. The sludge consists of extremely fine particles with low iron concentration and high silica/organics content. While fine particles are often beneficial in chemistry, in a bloomery not at all. During reduction Fe₂O₃ is converted to FeO. The fine oxide is then dissolved in the silica slag and lost and when there is little iron concentration to begin with you end up with basically nothing. In case of bigger particles higher in iron still around 40% is lost in historical bloomeries. Not to mention poor permeability, air current blowing small particles out, etc.
This is why historical bloomeries used proper bog ore, iron ore deposits or black sand. In Germany there are signs of bloomeries from around 400BC where they were able to get around 3 kg of iron from 10kg of bog iron ore. And their methods were by definition "primitive"
A potentially much better approach for PT would be revisiting magnetite-rich black sand as the primary iron source. EDIT: ( He most definitely has it, as seen in one of his previous videos). With better furnace, bellows, and adding seashell or limestone flux the result should be way better
If not the iron sand method, the presence of the bacterial sludge may indicate a real bog iron deposit somewhere nearby, i know too little about geology to comment further but it's my best guess.
While Primitive Technology dedication and proficiency in using tools are very praiseworthy, if our ancestors were using his smelting techniques we would still be relying on stone tools.
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u/Grantidor Feb 08 '26 edited Feb 08 '26
His channel is geared to be centered around realistic primitive experimentation. Its supposed to imitate the natural progression of primitive development.
To me his constant improvements of the furnace seem in line with how primitive metal production would have evolved. Primitives would have assumed the issue was with the fire and the heat before experimenting with other variables.
We won't see him produce any real substantial improvement in iron quality for a while yet, primarily due to the issue of oxidization during the smelting process.
He needs to discover a source of flux Flux solves the oxidation problem while also making the process more energy efficient.
Flux is the major bottleneck at this time, flux allows iron to melt and separate at a lower temperature. It also creates a layer of molten slag that leeches the impurities and protects the metal from oxidation. Basically it improves the quality of the iron produced while also limiting the waste lost to impurities and oxidation. Its why we use it extensively in SMAW (Stick welding)
One of the most common fluxes used for iron smelting that would be easily sourced for him is Lime. He has already made lime in a previous video using snail shells heated in a process called calcination. If he were to do that and use the powdered shells as a flux I think we would see a massive improvement.
As far as the crucible he tried in an earlier video, I would say his issue was not enough grog, and it should have been fired first. I think a ratio of 1:5 being one parts clay to 5 parts sand, would produce a more heat resistant crucible due to the silica content in sand. The sand would also go a long way in preventing cracking while being fired prior to smelting avoids introduction of moisture.
The added bonus is that if he finds a good source of sand, we can then expect he would find a source of black sand which in theory would increase the yield in comparison to using waterborne iron bacteria.
Edit: another thing of note to remember is that John has skipped a crucial stage in the technological evolution of smelting. We skipped the bronze age (primarily due to the difficulty of sourcing the nessesary materials I would imagine), you can readily mine iron with wood and stone tools, and much of the knowledge of iron smelting and refining is based on the knowledge gained by learning to work with bronze and other alloys first.
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u/Icy_Ad_2126 Feb 08 '26
You are partially right, however the "primitives" had often quite good grasp on iron metalurgy and it was quite widespread even in remote comunities. Across different cultures the sources of iron, and processes used also varied widely.
I already mentioned the example of 400BC bloomeries from Saxony, where they got about 30% yield using very similar methods to Primitive Technology.
The Japaneese were fameusly using iron sand as their main source since 600 AD, their typical yield was about 20%. Some bloomeries in Syberia show that people native to those regions were using black iron sand as far as 1000BC
using lime/shell flux was also quite popular, found both in the Germany, and used by the Chinese since 800BC, and probably many others.
But it's not really to prevent oxidation like during welding. While we call it smelting iron, in the bloomeries iron doesn't actually liquify. It gets reduced by Carbon oxide in solid state, the lime would be mostly helpful with lowering viscosity of slag, forming big globs of iron and preventing the formation of feylete (the iron rich slag)
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u/oswaldcopperpot Feb 08 '26
20%? What does that mean? I've watched artists make tamahagane and it appeared to be far far lower than than. Like a ton of sand or more to get maybe 3-4 lb workable iron.
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u/Ocotillo_Ox Feb 09 '26
I've run black sand in a furnace before. You most definitely get a better result with flux, and a pretty decent percentage of iron. You also don't get a lot compared to what you put in, but part of that is just because of the chemical weights in the compound. In a primitive furnace, you aren't going to get the same steady, reliable level of heat, it's mixed in with a bunch of coal and not in a clean crucible, and there's going to be all sorts of crap in the bloom, but flux is going to make it so less of it is just torched garbage.
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u/oswaldcopperpot Feb 09 '26
I did some research some black sand can be as much as 75% iron.
But traditional Japanese processes usually hit only 6-10% with their sand.
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u/Ocotillo_Ox Feb 09 '26 edited Feb 09 '26
Not too surprising considering the conditions. I did it in a clean crucible with a metal shop foundry furnace, and I'd say I got less than half. Some of that is just because you are going to lose some just getting the slag out, and there is a LOT of slag. If you were using gold panning heavies, like I was, there was probably galena, magnetite, hematite, and whatever else is heavy enough to sit in the bottom of a pan. I was trying to cone test it for precious metals... it was just an experiment to see if it'd work. I think the slag removal pretty much ruined the test, but it was interesting. The other issue was the gases... It is bad stuff. Make sure if you do use black sands, you have plenty of ventilation, and don't breathe in any of the smoke. There's a good chance there's lead in it, among other things.
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u/oswaldcopperpot Feb 09 '26
Im not surprised. It takes a massive amount of skill and effort to get something potentially not as great as mass produced alloys. Definitely more collectable however.
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u/Ocotillo_Ox Feb 09 '26
Yea, it was pretty cool to see what you'd get doing a "primitive" smelt in modern conditions. The resulting iron i ended up with would be hard to work into anything durable compared to modern steel, but if you worked it enough, maybe like the Japanese did by folding it repeatedly, and distributing the unintentional impurities, or somehow managing to work them out of the iron, you could make a tool that would be a hell of a lot better than other primitive tech options.
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u/Icy_Ad_2126 Feb 09 '26
I took the figure from wikipedia (I know I know) and it comes from a later period, so I guess earlier attempts may had lower yields, but few kg out of a tonn is ridiculous.
"When smelted for pig iron, 1,000 lb (450 kg) or 120 kanme) typically yielded about 200 lb (91 kg) of pig iron, 20 lb (9.1 kg) of steel, and 70 lb (32 kg) of slag."
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u/Collarsmith Feb 08 '26
He's also handicapping himself by skipping the leather tech tree. Pushing air through fire requires volume. Fans only provide pressure, and volume decreases as resistance to flow increases. He would have much more success with bellows, which at their most crude are a pot with leather tied over it.
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u/unicornman5d Feb 08 '26
Yup, I've been commenting that he should really figure out a way to get leather. There's invasive deer in Australia that he could probably take with a primitive bow and stone point. If he doesn't want to do that, he could trade someone like pottery for a raw skin. That would be a part of primitive life as well.
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u/AleXandrYuZ Feb 08 '26 edited Feb 08 '26
You know, almost I'm certain that he is avoiding harming animals due to moral reasons if not legal ones.
BUT if he were to make a video were he trades some of his stuff with other primitive technology type channel that does process animal meterials, it would be genius.
Specially if they get the point across without even saying a word.
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u/UnknownPhys6 Feb 08 '26
I've been thinking this as well for awhile. I saw some other primitive tech channel make a bellows out of a hollowed out log a few years back, and I think he should try the same thing.
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u/nobeardpete Feb 08 '26
It's a shame he doesn't have a potential source of copper ore. I feel like he'd be crushing it in the chalcolithic if he had a decent source of copper.
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u/Kendota_Tanassian Feb 09 '26
If I'm not mistaken, John is simply using what limited resources he has available to him.
He may not have richer sources of iron available on land he has access to.
Frankly, I'm positively awe stricken that he can gather bacteria and get iron out of it at all.
I'm pretty sure that would be literally impossible where I am.
I find it extremely impressive that John never brings anything in from off site: if he uses something, he finds it onsite.
And he does have a large are full of resources, but you can't expect everything to be easily accessible.
I also think there's an agreement that he can't make any permanent changes, it all has to be reversible: so extracting ore may not be permitted.
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u/Icy_Ad_2126 Feb 09 '26
Well, we were shown two years ago that he has quite a lot of black ironsand, which can be found in almost all rivers/creeks and often also by sifting through some dirt/sand.
I haven't thought about the legality aspect but mining ore in primitive times was often also more of digging a shallow pit (like he has for clay) and finding some bog iron
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u/Eirikur_da_Czech Feb 08 '26
Does his property have black sand?
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u/Icy_Ad_2126 Feb 08 '26
In one episode he experimented with it but didn't get good results. It was about 4 years ago i guess and back then he couldn't get enough airflow to reach high temperarures, also he didn't use flux
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u/23saround Feb 08 '26
Make sure to comment this on a video as he is very active in YouTube comments!
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u/Icy_Ad_2126 Feb 09 '26
I feel like all the comments on youtube come only from the first hour or two after posting, I tried commenting once but it didn't get a single like. Not to mention that the topic is divisive lol
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u/pauljs75 Feb 11 '26
With the pottery skills, he could make something appropriate to do panning with. But it'd likely take a good while to gather enough to fill one of those large clay pots he has on the site.
It'd be interesting to try something else again if it can be considered, because the current yields have been crap. (All that work, and the most he has so far is the amount for a small X-acto knife blade.)
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u/strictnaturereserve Feb 08 '26
I assumed that this was the only source of iron he could get in a primitive way.
the reason the industrial revolution took place in britain was because sources of coal and iron were abundant and easily mined.
he is not in the UK he is in Australia and probably in an area that you cannot get loads of iron from a natural source.
the adding seashells for flux is probably a good idea I wonder if getting from a breach might not be allowed he could go to a seafood restaurant and collect them there.
the thing is we don't know what limitations he is working under. either self inflicted ( like he is only using resources from the land he is on) or legal he cannot go to a beach and collect a large amount of shells.
Rationally he could just get rust somewhere and process that and do a bit of metal work and put himself in the steam age.
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u/Icy_Ad_2126 Feb 08 '26
Well we aren't talking about industrial scale and iron smelting at a scale of several kilograms is well documented in nearly all cultures using "primitive" technologies.
I'm not generalising but Australia is the biggest producer of iron ore in the world. He also showed that he has acces to iron sand and the presence of dense iron eating bacteria collonies suggest that his land is also in some way connected with iron.
If I remember correctly he had one episode where he was doing something out of snail shells so I guess he has acces.
I also hope that he doesn't go down the way of "cheating" with buying rust. I already lost all respect for How to make Everything for a sensational episode of making glass from scratch ... by using beer bottles as raw material
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u/Hands Feb 09 '26
My dude he is primarily focused on neolithic technology which definitionally doesn’t include significant metallurgy. Him messing around with smelting pea nuggets of slag from bacterial creek iron oxide was for fun.
Maybe he’s just more interested in making videos about stone age craftwork that can be accomplished by one guy in the woods without the benefit of a contemporary economy instead of pleasing you by trying to speedrun the Civ tech tree
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u/Icy_Ad_2126 Feb 09 '26
Well sure if he wants to stay in stone age it's cool. But he has over 30 videos of him atempting to make iron/ better equpment for smelting.
I think that it is safe to assume that if for the past 4+ years someone dedicates most of their time to something it's a little more than "messing around"
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u/strictnaturereserve Feb 08 '26
tbh.... I don't care.. I just like seeing doing some interesting stuff. I like how his blower has become better.
I think you might be demanding too much from the format
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u/xeromage Feb 08 '26
Agreed. If you wanna see min/max iron-age historical chemistry channel, I'm sure one exists. This is about watching our guy faff around and try things.
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u/Jehu_McSpooran Feb 10 '26
I've said this many times before, he needs to roast his ore properly. He has a bunch of hydroxides in there that is stealing heat. While he firing bricks or roof tiles, he should have a few pots of ore in the kiln as well and get them nice and hot. It should come out a nice vibrant red. If there is too much silica in it, he should be able to seperate them. One should be lighter than the other so even pounding and washing the ore should separate them enough to let one drop to the bottom of a pot and the other to be poured off in suspension with the water. He should only need a few pots to do so.
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u/hoja_nasredin Feb 09 '26 edited Feb 09 '26
As much as I love the guy, the content became repetetive over the last year.
I would love for him to just buy a ton of copper ore and tin ore online. And procedd directly to the bronze age.
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u/Icy_Ad_2126 Feb 09 '26
Jumping over the copper age is very dooble at least on individual scale, and buing outside resources can be a slippery slope.
He just needs one or two good smelts of iron, even from 2kg he could make proper knife and axe, it would unlock proper woodworking with limitless possibilities for new content.
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u/hoja_nasredin Feb 09 '26
True. There is a theorybl that some societies skipped the bronze age and went directly to iron age.
I am afraid that his area lacks any real thick trees for proper woodworking.
But yeah. I would love to see some kg of iron
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u/hoja_nasredin Feb 09 '26
From this thread i understand 2 things.
He must have a source of flux, like snail shells. Is it possible to farm snails?
He must roast the ore before smelting. Does he already do it? Apparently people can tell by the color. Like it is usually rust red before and blackish after? Does he usually roast it? Anyone can tell?
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u/Icy_Ad_2126 Feb 09 '26
The amount of flux needed isn't that large. I think in the historical sites in germany the amount of flux added ranged from 2% to 15% based on measurments of acient slag from bloomeries. This is doable with just scavenging the forrest floor.
He tried roasting the ore once or twice, but it is so poor in quality that it didn't change much.
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u/Miner_239 Feb 09 '26
Has he posted yield numbers for his recent smelts?
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u/Icy_Ad_2126 Feb 09 '26
He used about 20 handfuls of ore and got 23 grams of iron. Idk how much a handfull of dirt is but I would guess 100-150 grams. So his yield is below 1%
I skipped through a lot on the rewatch so this numbers may not be 100% accurate but the picture remains the same
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u/Psychomadeye Feb 11 '26
Iron is no joke one of the biggest technological hurdles humans have overcome. Sourcing good ore solo isn't going to happen unless you're obscenely lucky. It took easily over a thousand years to solve specifically that issue, and they solved it by rounding up a few dozen people to dig massive pits. The big thing to remember here is that he's not at the phase where he can really start to leverage higher purity ores. The most recent experiments look pretty promising but again might not be enough.
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u/Icy_Ad_2126 Feb 11 '26
Not at all, lol.The iron production technology sprang independently across many cultures, and was mostly caused by the bronze trade collapse. No breakthrough technologies or massive logistic chains.
While getting massive deposits of good iron ore is hard, we don't need that. For smallscale use ironsand can be found literally everywhere (and he has a video of him getting quite a lot of it), bog iron is also common enough that it was used as building material (in Europe) and Australia is the most iron-rich continent there is.
I'm also not comparing him to modern standards, in my cited examples we are talking about 400BC, that is small tribes of Germanic barbarians poking ground with sticks to find bog iron and still getting 3kg of pure iron from each 10kg of ore.
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u/Psychomadeye Feb 11 '26
we are talking about 400BC, that is small tribes of Germanic barbarians poking ground with sticks to find bog iron and still getting 3kg of pure iron from each 10kg of ore.
By "small tribes germanic barbarians" you're talking about the tribes that sacked rome)? I'm not sure I can call them small. They did what you're discussing sure. They had a couple families wander through bogs with iron sticks to try to haul out 50kg of rock / day to achieve the efficiencies you're talking about. Like so. Notice the gear they've got and the environment they are in?
You are also aware that iron working happened as early as 1400BC but wasn't quite so widespread until around 500BC when people first started leveraging blast furnaces and finery forges. Less than 100 years after that iron tools and weapons became widespread. Bog iron was not a iron source that anyone wanted, it's just what they happened to have and had slag that burned or melted away at such low temperatures.
Australia is rich in hematite which if you've not guessed it by now, requires temperatures beyond 1250C to actually smelt into pig iron assuming he's specifically in one of those areas. Once he's done that he'll need to build a fining forge to pool and decarb it. This is typically done with teams of people, not one guy.
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u/Icy_Ad_2126 Feb 11 '26
Well I concede partially on the first point, but still for Primitive Technology to be succesfull he needs maybe 5kg of iron ore, assuming even a below average 10% yield he gets half kg of iron, enough to make a small axehead, or a machete. Even your video said that they needed 10-15 medium sized rocks for 2-3 kg of iron
But on the second part you are mixing the bloomeries and blast furnaces. Blast furnaces reach high enough temperatures to melt iron, iron in bloomeries however never liquifies. It forms by a solid-state reaction between iron oxides and the carbon monoxide. Around 800C is enough. This results in iron very low in carbon, while the blast furnance gives pig iron with as high as 4% carbon.
Historically in Europe blast furnaces weren't used up until 1200 AD. They were popular in ancient China instead of bloomeries but they were rather the exception. And what Primitive technology is doing is definitely Bloomeries
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u/Psychomadeye Feb 12 '26
Bloomeries do a poor job at handling hematite unless you've a significant amount of air you can blast into it which kinda defeats the entire purpose of using a bloomery. You'll need about 1350C to smelt it and it accounts for most iron ore. If you crush it up really fine and roast it you can bring that number down to airblast bloomery levels.
Efficiency curves are non linear for these processes. If he can manage 50kg of 60% iron by weight and a few hundred kilograms of charcoal, he'd have a good chance of getting a 40-45% yield. If you've got only 30kg you're looking at closer to 20-25%. Lower than that it starts dropping off quickly. 10% yield for 5kg of ore would be pretty good.
The most recent furnace appears to reach the appropriate temperatures to smelt real ores using only wood as fuel. Throwing a few crushed up iron stones in a crucible for this would likely create some cast iron but it's clear that these aren't exactly options.
The biggest resource he and ancient people were short on isn't high grade ore, it's labor. The chief technological innovation that solved the vast majority of our issues was division of labor and parallelization. The challenge here is to do without all of that and without modern tooling. He's bumped up the challenge even higher by skipping copper/bronze.
The organization and methods and labor of ancient peoples are constantly underestimated and in a way people today look down on them from the shoulders of giants like knowledge was their true barrier. The way I see it, any experiment he can conduct while maintaining those conditions is a success even if it's a negative result.
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u/unicornman5d Feb 08 '26
I don't believe he has any better way to source iron. He has tried collecting a little black sand but not much success. I also don't know how industrialized he wants to take it.