Primitive Technology: One-Way Blower Iron Smelt & Forging Experiment
Added 2024-02-29 21:57:45 +0000 UTCI tested the one-way spinning blower in an iron smelt and it is more effective than the previous both way spinning blower. Using the same amount of ore and charcoal, the original blower yielded 30 g of iron where as the new blower yielded 51 g. The previous all time record was 41 g from several years ago but the new blower it beat that by 10 g on its first run. The energy saved by having the fan spin constantly in one direction no doubt contributes to the better performance of the blower. As with the old blower, the new one produces high carbon iron prills (cast iron blobs) in slag. The brittle slag crushes easily while the iron prills remain intact to be picked out by hand or gravity separated with panning. The iron prills were also quite large and more numerous than smelts done with the old blower. Also in this video is a forging experiment. Using iron from previous smelts, a crude bar of iron was melted together into in a mold. The iron prills were placed in a clay mold, put into a forge and heated with charcoal using a flat nozzle tuyere. The process produced a 8cm long, 2.5cm wide bar. This bar was then heated to a red heat with wood for a while to anneal it, making it malleable in theory. However, when I tried to forge it, it crumbled apart. The waste iron was set aside in a pot for re-smelting so as not to lose it.
Comments
Good question, it's basically simplicity. It's the wet season at the moment and I currently don't have a water proof structure large enough to house a charcoal making kiln along with other furnaces and dry fire wood. So instead I have a 50 cm diameter pit in the permanent brick shelter for making smaller batches in shorter periods of time than a large scale kiln. Efficiency (wood to charcoal) is pretty good compared to the mound. Labor and time is less for the pit than the mound also, as there is no mud cap to mix and apply. Skill needed is also less for the pit than the mound, attention must be paid to the air entries to see when to close them up (when fire reaches them)in the mound method. The Benefit of the mound method is greater quality, as the charcoal tends to be denser and drier than charcoal doused with water, although if allowed to dry the charcoal seems to give similar results during smelting. Also, there seems to be a better economy of scale associated with the mound method, it may take longer to make but the overall labor may be less. Thanks.
Primitive Technology
2024-03-10 01:35:11 +0000 UTCHwy, cool video! This time, you're using the pit method (kon tiki) for making charcoal instead of a classical earth kiln. Why? Can you compare both methods regarding e.g. efficiency, ...?
Hizuna
2024-03-09 20:36:22 +0000 UTCThanks, good to test them out.
Primitive Technology
2024-03-01 23:16:51 +0000 UTCLove the viewer suggestion reviews and the continuous loop!
Julian Gonggrijp
2024-03-01 22:34:01 +0000 UTCI'll improve my metallurgy first and then see what's possible. I'm open to suggestions if you have any. Machinery would be good. Thanks.
Primitive Technology
2024-03-01 11:37:19 +0000 UTCDo you have an idea of your goal later in the project ? Is there a particular machinery or furniture you wish to attend that is not possible to make now ?
Hélo Jacquot
2024-03-01 11:26:11 +0000 UTCA knife or axe would be good I think. Then more complex tools after that point. Once I can forge the iron it will be easier to make such things. I can also recycle the iron I use in experiments that fail, just put them into the next smelt to recover the iron. Thanks.
Primitive Technology
2024-03-01 11:00:24 +0000 UTCLots of people may have asked the question, but what is the main goal tool you ll want to make in the forge ? - - it seems to me that the first idea would be a knife, but so far you've managed to cut whatever you want with a sharpened stone - some kind of saw? But it seems impossible to forge teeth without other tools at the moment. - any improvements for the forge? Maybe bellows tips or some kind of firebrand? - A hammer? I have the impression that this would require too much iron for it to be heavy. - if you want to work the land, a spade would be useful, or harpoons for fish or tips for arrow -A long stake to work the soil better, or to use in the forge? It can be also used as a lever or helping moving pots - a pot to heat different components more easily? -a wheel because it can be used just about anywhere?
Hélo Jacquot
2024-03-01 10:33:34 +0000 UTCIt's a good way to get ideas, the 2 stick method was suggested to me by viewers and turned out to be good. I was too close to the problem to think of that solution and then the viewers pointed it out. Thanks again.
Primitive Technology
2024-03-01 07:31:41 +0000 UTCYou are amazing that way! You are very interactive, makes your whole thing feel like a sort of collaboration.
Amy Tobol
2024-03-01 06:37:21 +0000 UTCThanks Amy, Some of those were viewer suggestions, good to test them out. Will keep the fire making segments coming.
Primitive Technology
2024-03-01 05:01:25 +0000 UTCI enjoyed you exploring other ideas on how to turn the blower. I also enjoyed watching you make fire, thanks! <3
Amy Tobol
2024-03-01 04:23:24 +0000 UTCGood to talk to a blacksmith, yes to all your points. As you mention, perhaps remelting cast iron in a hearth is the right decision as per the finery forges of the late medieval period when blast furnaces appeared. I've also read of ancient Chinese "stir fried" steel which seems to be the same method. In both cases the iron is melted in front of an air blast which decarburizes it to make it forgeable. I made a video on decarburizing cast iron in which I had some success in being able to hammer a mass of iron flat after melting the prills in an open hearth. Feel free to tell me more about decarburizing cast iron if you have experience, I'm just going off text book and internet information so far and seeing what works. Much appreciated.
Primitive Technology
2024-03-01 00:56:03 +0000 UTCMuch appreciated, glad to produce content people really enjoy. Yes, it's not all a failure either because I can recycle scrap iron in future smelts (good idea for upcoming an video). It might make a forgeable mass if re-smelted. I originally made circular furnaces (they work fine by the way, I just switched to square brick ones because it's faster to build). The reason I don't have tangential air entries for furnaces is because the charcoal lumps disrupt the flow and it just makes a race way in the coals next to the furnace wall. As for a kiln however, a tangential firebox would be interesting as there are no such obstacles. Maybe a vortex kiln with a circular sagar (filled with pots) in the middle for the flames to circle would be a good idea. I've wanted to try one for a while but didn't get around to it yet. Thanks.
Primitive Technology
2024-03-01 00:44:04 +0000 UTCCast iron is really difficult to forge, as you found out, particularly with the extremely high carbon content you probably have. I guesstimate about 4-6% (for reference, most modern steels have less than 1% carbon). I don't think annealing it did anything for its forgeability, but decarbonizing probably helped a lot, so I think you're right about it being the way forward. Annealing is mostly useful for cold forming, but even then this steel has so much carbon it's probably mostly entirely in its cementite form (really hard and brittle) when cold. To make decarbonizing more efficient you need lots of airflow and as little CO/CO2 as possible, and preferably really hot air. Increasing surface area would be great as the decarbonizing works from the outside in. You can increase decarbonization by keeping it at a high temperature (not above 1150°c) for longer with continuously diminishing results, especially in the presence of burning coal. You can also improve it by then slowly decreasing the temperature while maintaining airflow, as the carbon saturation point of iron decreases with temperature, but below ~750°c the decarbonization stops completely. No camera is good at filming incandescent materials, so it's really hard to judge what temperatures you're getting, but you don't need more than a red-orange heat to forge and the material would probably hold together better than at a high yellow/white, which it kinda looked like you're hitting. For reference, I am a professional blacksmith and I think historical iron is really interesting, so I've read a lot about it. I don't have a degree in it or anything (yet), but I'd be more than happy to share what knowledge I have or answer any specific questions if you have them! Really loving the metallurgy series; thank you for the videos!
804R
2024-03-01 00:40:14 +0000 UTCI love this what your doing, it's like I get to live my fantasy life through you. Plus your inspiring and what you do is inspiring because you don't separate your failures from your successes, it's just experimenting and learning. Having said that have you thought of making a circular furnace like ancient cultures i.e. the Africans and having the blower go in on an angle to the side so it creates a vortex and get greater heat?
Sam Gordon
2024-03-01 00:15:26 +0000 UTCIt's high in silica. Might have a similar function to quarts as a flux. Thanks.
Primitive Technology
2024-02-29 23:56:18 +0000 UTCIf you watch traditional swordsmiths in Japan that use Tamahagane when they are forging it they use rice straw ash as their flux.
Kenneth Crips
2024-02-29 23:41:33 +0000 UTCThanks Kenneth, it's on my reading list now.
Primitive Technology
2024-02-29 23:37:55 +0000 UTCIn theory yes but in practice there is a zone of oxidation I've read in front of the nozzle. I'll keep it in mind though. Thanks.
Primitive Technology
2024-02-29 23:37:06 +0000 UTCThat would be my next step, see the method where I used a loop of rope around the rotor. I'd probably rig up a separate wheels on another frame. Thanks.
Primitive Technology
2024-02-29 23:36:06 +0000 UTCThat may be the case. If iron is high in carbon it should be forged at a low heat. Cast iron can be forged but with many low red reheatings. Thanks.
Primitive Technology
2024-02-29 23:35:00 +0000 UTCThat was the roasted ore and the ash from the wood during roasting. The slag is the iron bacteria which is iron oxide and other impurities like mud in the water. Also, charcoal contributes some slag as the wood takes up silica from the soil. Thanks.
Primitive Technology
2024-02-29 23:33:37 +0000 UTCYes, my bad. Didn't press publish on the subtitle. Should be good now. Thanks.
Primitive Technology
2024-02-29 23:31:45 +0000 UTChttps://warehamforgeblog.blogspot.com/2015/04/ancient-metals-ancient-fluxes.html
Kenneth Crips
2024-02-29 23:12:59 +0000 UTCFantastic. How interesting. If the iron is in contact with the charcoal, does that recarburize it I wonder.
Ken Clark
2024-02-29 23:00:15 +0000 UTCTake a look at a yarn winder, it is within your tech level and would make a dandy wheel for your blower using the technique you used with you hands.
Kenneth Crips
2024-02-29 22:57:09 +0000 UTCShame you weren't able to forge the bar. I think the problems was you heated the bar to hot. But i'm not an expert, just a little experience. I look forward to seeing how you develop the blower further.
Sam Gordon
2024-02-29 22:38:08 +0000 UTCDid anyone see what he was using for flux in the smelting? And if nothing, then where did all the slag in the bloom come from?
Bruce Taylor
2024-02-29 22:33:22 +0000 UTCSad about the subtitles, love your explanation on them... thanks for the video in any case. EDIT: Huh, I started too quickly to see the video, there are subs now!
Faralis
2024-02-29 22:00:46 +0000 UTC
