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Hello All,

Thanks for the enthusiasm. I'm really looking forward to seeing what other Bloomers and Buttons experimenters will do with these new ideas. Since I know that all of you are just like me, I also know that everyone will build something slightly different depending on what materials they have lying around. When you do try your hand at making simple steel, please, come back here to this Forum and tell us what you've discovered!


Maybe the first question to address is the type of scrap that I used for making Jesus's ingots. The initial goal of my experiments was to design a furnace that would produce a nice round dense ingot. Because of this I didn't think much about the type of iron that I was melting just the shape and quantity. I scoured the neighborhood for any kind of iron rod I could find and came home with a couple pieces of skinny rebar and a half dozen of those iron stakes that people use to string an electric fence around their property (the goats had already escaped). The chemistry of that kind of iron is totally unknown. It is just great good fortune that the resulting steel produces a nice hamon. I couldn't have predicted that from the start. Jesus, thanks again for finding this out.


What I did learn by melting all of this random scrap was that the furnace works best with 1/4" to 3/8" rods about a foot long, longer works but you have to keep messing with them to keep them from tilting over, and trying to melt 1/2" rebar just about choked this tiny furnace. Also, this little furnace can only hold just so much iron; when I tried to make a three pound ingot the iron filled up the bottom and the level rose up closer to the blow hole, the top of the ingot was by then being burned by the air blast and the resulting iron oxide immediately reacted with the clay furnace wall, turning it into silly puddy. You already know what happens next. Fortunately patching and repairing a furnace like this is effortless.


Best to all


thank you skip,

for sharing your experience. I want to know how you estimate the right level of ingot and blow hole. for my practice I well know that ıf one could not estimate it the last product will iron oxide and useless. I think also the bottom of the furnace shape plays critical role for getting suitable condition. what do you think?


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I did a second run in my little furnace, this time using beer bottle caps for the donor metal. I found a nice bit of very high carbon steel for my efforts :)

The first run using wrought iron wasnt what I wanted for a blade so I broke it up, stacked it with the new bloom and folded it to 2500 layers. The blade made from this billet hardened nicely in oil. I did have a few inclusions in the billet but that was my fault, not the steel!


Here is the results...




Thanks Jesus for inspiring me to start this journey, and Thanks Skip for showing me the way!



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  • 2 weeks later...

so, I have a question.. Im short of clay.. and such, and decided to make my furnace from firebrick, its rectangular in construction, but I rounded the chamber with ceramic clay, and charcoal fines kneaded together.. and it is otherwise constructed like the one shown in this thread, I was wondering if the clay will be enough of a flux on its own.. I ran a preheat yesterday, to fire it, and ended up with alot of slag somehow.. probably from the clay, but it wasn't near hot enough to actually melt steel.. I'll tink with it tomorrow again, but yeah, just wondering if making it from firebricks is going to work at all :P

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I'm really no expert on this, but since no one else is answering I'll just say that I can't see why you shouldn't be able to build a working furnace out of firebrick, as long as you have some clay in there to form a slag bath. (In the presence of iron oxide even the hard firebricks might slag up a little, depending on their alumina content -- but I wouldn't count exclusively on that.) But it may take longer to heat up, because the dense bricks will form a heat sink.


I'm not sure what you mean about the clay being "enough of a flux on its own." Are you asking whether you need to add flux to the smelt?

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Sorry I missed the follow up question. The refractory brick should work but I would suspect that the thickness of the wall will be a factor to account for. If it doesn't work the first time around don't discard the furnace. There should be some erosion of the brick wall and that will make the second run more effective. Eventually the wall will reach a thickness that will balance the heat exchange with the outside. These are all experimental furnaces and I will encourage any one to try and report back.

Mizzou should work too.

Randy, that's a nice looking steel pattern.

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... my other problem is the amount of sparks that come shooting out of this thing. I'm running my air supply pretty hard and there's a lot of velocity, could I open up the blow hole and get more air with less pressure? or should I make the stack taller?



Matt, Nice ingots!

I'd try all of the changes you mention. Generally I don't have many sparks blowing out of the furnace and when I do it means that the iron is too close to the blast. I minimize the sparking by re-placing the iron as far away from the blowhole as possible. Other than that, there isn't any magic number for furnace size vs. air rate vs. blow hole size. Just watch for a nice welding heat, that certain pink-white glow of the escaping gases, and tune into what seems to work.

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I want to know how you estimate the right level of ingot and blow hole. I think also the bottom of the furnace shape plays critical role for getting suitable condition. what do you think?



I've delayed posting a response to your question because there isn't a definitive answer yet. Here's the factual info we have right now. My standardized melt consists of 750gm of iron, therefor all of the ingots should be about the same thickness.


2 Inches

With a distance from the blow hole to the bottom of the furnace of approximately 2 inches, the ingot produced contained almost no carbon. That is, the mild steel was decarburized to nearly pure ferrite. The process probably also purified the ingot of Mn and S and Si and anything else for that matter. So in this case it was the relative position of the top of the ingot to the air blast that determined the carbon content.


4 Inches

With a distance of 4 inches there are two different results. If I removed the ingot as quickly as possible after it had melted then I seemed to get a hyper-eutectoid steel (C greater than .7%) If I allowed the ingot to boil in the furnace for another 15 or 30 minutes then I most likely ended up with white cast iron (C greater than 1.5%) and the ingot would have other elements dissolved in it, Mn, Si, etc. So in this case we have two controlling factors, initially the carbon content is determined by what the iron has picked up while it was melting above the tuyere, but as time goes on the ingot absorbs carbon from the environment.


6 Inches

Only one experiment has been done with a distance of 6 inches and a long ingot boil. The product was a nice puck of white cast iron.


Samples have been sent to the metallurgist. I'll post the results when I get them.


Close up of the extreme sparks from a high carbon sample.


Edited by Skip Williams
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Hey Skip Thanks for the info!

When I say sparks I don't think it's the steel shooting sparks I think it's the charcoal. I was hoping a taller stack would tame the blast from shooting those embers(the word I should have used in the first place) up in the air. Now I did put some cast iron shavings that I get from a friends machine shop in the furnace and WOW it was like the fourth of July! Sparks every were! I'm thinking of putting a hole on the bottom of the next furnace that I'll fill with the charcoal sand mixture and then poke a piece of rebar up through it to help get the ingot out. Hopefully I'll cause less damage to the furnace that way.



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When I say sparks I don't think it's the steel shooting sparks I think it's the charcoal.

Yeah Matt, You're right. This little furnace throws out a lot of sparks. The same is true for Bloomery furnaces and Tatara furnaces. Since so few of us forge with charcoal this lovely little fact has been forgotten. The only way to cut down on the sparks is to decrease the air rate per cross sectional area of the furnace. Oops let me say that a different way. Keep the air rate the same but make the furnace wider and that will help some, but charcoal dust is so light weight it's gonna come flying out of there no matter what. Ya could run the furnace in front of your smithing hearth and have the sparks fly up the chimney. And sift the fines from the charcoal after you break it up!


Let us know how the pokey hole in the bottom works out. That's an interesting idea.

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  • 2 months later...

ok this was my second try (the first was a flop) this time i used 1/4" rebar, 1/8" X 1/4" hot rolled sheet, 1/4" W1 it worked better but the ingot looks a little diferent than the ones posted. I have worked it down to 1 1/8" X 5" at welding heat it was very hard under the hammer is that normal? Thanks Scott







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Hi Scott



It looks like liquid in some places...

If C cont is hi part of bloom are hard, but soon as you forge it ( welds folds..)

you greate small grainsize and about A1 temps you might see some superplasticity.

I find this in my last bloom douring forging cycles.


It would be nice to see sparktest....I think it has nice spark in some places.


If you dont mind asking...

Furnace of yours....Its cool.

If im not totally wrong is it at same time smalting furnace and charcoal forge...Thats cool idea...I like it.


Good work.





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Hi Niko here are a fue shots of the sparks from different spots on the billet. The forge is the first propane forge i made, it had a cast refractory liner and took a long time to get hot, so before i changed to a k-wool liner i thought i'd give smelting a try. I will make a new one just for smelting in a fue months. Thanks Scott







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Hey Scott

That looks great! Those sparks (to me) look 1.5% carbon. How big is that ingot? I think it's going to be a little hard until you work some more carbon out of it, keep flattening and folding and it should get easier. You're going to get me cranked up to make a few runs with my small furnace! And I also have all the steel I sifted out of the Maryland smelt to do something with!



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  • 1 month later...

I'm about ready to jump into this... but I have one more question... do you think it's possible to use this furnace as a mini smelter, to reduce ore in first, and then run it through again to make steel?



Having just re-read the Catalan forge thread, I think that adding a little water to the mix would help the reduction rate, if Alan's hypothesis is right. Wetting down my ore a little, and tossing it in a 6" wide, 12" high furnace, with a downward tuyere around 4 inches from the bowl bottom, with a ball clay liner ( in a 8" riser sleeve shell) is the plan. I'm hoping to get ore reduced to iron, do that for a couple runs and squish it down into small pieces, then feed those again to the furnace for carbon uptake. From that, hopefully get a knife.


Any thoughts before I totally commit to this?

Edited by Christopher Price
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  • 2 weeks later...

Scott, that is a great looking ingot. I hope you get something nice out of it.


The sparks suggest that it is 1 to 1.5% carbon. From the pics you posted it appears that the ingot isn't crumbly under the hammer, just very hard.


Keep us updated on your progress.

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  • 2 weeks later...

Fistly thanks for the post I have had a feeling for years and suspected the japanese were making what i call maliable iron drive carbon into it and you have a form of one could say mild steel ( but not as we know it ) the thing we know as high carbon steel has more junk added so in essence they correct term for this would be Maliable iron in billet form add to this the forge folding again in charcoal acording to the book The Craft of the Japanese Sword ,Yoshindo Yoshihara prefers 0.7 % carbon content (page 30 ) over 0.8 it will become brittle but descibes it as iron


anyway i made Furnace so now to let it harden

thanks again tell










i made a cage of chicken wire used sandy clay / fire clay /straw mix rather like an addobi mix well mixed seems to be hardening well so far

the wire will make it easyer to repair too thanks tell

Edited by tell
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Well I fired the beast up used a regulated leaf blower ( Ajustable Calmp on the hose ha ha ) but i got a 16lb bloom of silver gray and black bloom now to smash it up

now a tap hole in the bottom would be great a taperd bowl check seeing the clay is free just smash it to get the bloom out

with the leaf blowere you can make a deeper bowl and bigger bloom stop adding scrap when the stuff bubbles and you cas see it nr the top but tapping the slag is a definate yes












as you can see the scales whanted to go round again all up good fun thanks again guys

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If looks like you push the limit of the furnace. Our general approach has been to make a small "bloom" of about 500-800 grams in weight that can be extracted without breaking the furnace. Then keep on making more. I wonder if you could give us an idea of the carbon content of that mass by doing a spark test in several spots.

Congrats on the results.

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Yah mate lesson learnd about bloom size to say its heavy for it's size would be an understatment silver sparkle grain approx the size of a pin head at the higher end then smaller ill try for a pick but im going to have to get a drop saw on this baby as for the furnace no problem making another plenty of clay on our joint i think the advice on dropping it in water was a boo boo im goint to let cool naturaly it should be easyer to smash or cut then but i will try and keep you posted guys

thanks again i cleand up the off cuts and crack'd blade tin nicely 1050 1065 1075 re bar off cuts spring steel mild steel all into the mix and you can see were the crap addertives boiled out i sent my mate 1 .1/2 lb to try so he will have some comments i hope


cheers tell




sorry if the pics no good bloody camera wont do any closes even on super macro ,

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Hello everybody,

Jesus and Skip, thanks a lot for letting me follow your steps. So I just jumped in it and these are the results of all my mud malaxation and steel scrap incinerations.

I made My furnace out of clay from my garden, I digged deep enough to get a pure mix of clay and sand. After a night soaking with water, I mixed the straw, then build my furnace around chichen wire, and put fire in it as it was still wet. If you did yours around a soda bottle, mine is slightly bigger.


As you see the furnace on the pictures, I already did 3 runs in it, and the bloom is each time almost exactly the amount of scrap weight I put in, That is beetween 600g and 900g

I just had to redo the inside lining with the charcoal fines and clay/sand mix, but I guess if you take your bloom at the right time, your lining can survive for one more run.

This simple and natural material mix is amazing. Inside the furnace is raging hell and you can still touch the outside.

I started to forge a piece from two of the blooms togeather by compacting the chunks I've cut off in a single bar and welding them. So I don't make any sorting, just to see what is going to happen. After two folds, I still have some impurities. Is that normal ?


The stone I use to regulate the air flow is just in front of the tuyère, so I can peep inside!







Edited by igrec
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