Bloomery fail questions.

[Kreg Whitehead]

Been wanting to try this for a while and finally had a nice day here and a day off at the same time.

Did my best to copy the 7 brick dealio, Got a bag of cowboy charcoal(next time I will buy 2 for a run) and gave it a go.

I used 12 rows of pneumatic framing nails for the charge....2 at a time(maybe thats a problem idk).

I did not have the luxury of a way to weigh it.....but I am pretty certain what ever it is I took out weighed more than the orig charge.

Also I should probably add that I lined the bottom with some large chunks of mesquite because I was worried about running short on charcoal....maybe thats a problem idk.

I would appear to have made some kind of a cross between cast iron and lava.

Its a lot more sparkly in person than the pic.....and there were a handful of smaller pieces not in the pic that broke off.

I will try to edit in a vid of it shortly after I put the last charge in.

Would being to hot/too much air cause this??

[Alan Longmire]

I'd guess a little too much air.  It should be less bubbly-looking.  If the nails were plated that might cause some problems too...  Zinc will vaporize out, but you never know what else is on there. I wouldn't think the mesquite underneath would do much as long as it was completely dry.  If it had any moisture that could mess with things, though.  

 

Does it spark like cast, or is it just a pile of goo if you hit it on the grinder?  

[Joshua States]

That's a really cool sculpture! It looks like Yoda on the Dark Side.

Seriously though, congrats on your first melt.

Sorry I can't diagnose what problem you have, but maybe @Aiden CC can make a suggestion.

Did you take any pics of the furnace setup? I seem to remember that the tuyer angle and height is critical

[Kreg Whitehead]

I wanted to post the vid but here is a pic.

The tuyer is at a slight downward angle from level...maybe sticking an inch or 2 in.

If you look close you can see flame blowing out of the bottom on the far side.

I am not sure of anything.

I think I need to let it get hotter before I start charging it.....will have more fuel next time.

You can see some of the wood trapped in yoda stuck on the bottom.

I also think I had too much air going worried that I was lacking fuel/coal for the job.

Not sure what to think about the nails other than the gun died and I have resisted the urge to toss em for 5 years and was hoping they would be a good candidate.

As far as spark test I am not sure what cast looks like but this was pretty dismal.....very little sparks period.

Its probably impossible to tell or see but the top of yodas left shoulder is the spot I put to the grinder. 

[Aiden CC]

Good on you for getting into it! There is definitely a learning curve for this process. Are you cutting the charcoal before using it? It's hard to tell, but it looks like there are some large pieces in the photo. I usually will buy 2-3 bags of charcoal, Royal Oak is my personal favorite, mostly because it isn't very "sparky" while burning and cracks less (maybe it's a bit dryer than other brands"), then I go through and make sure all the pieces are under around 1-1.5" on their largest dimension. Most of the pieces are small enough out of the bag, but I cut the big ones down with a big knife. This helps keep the appropriate spacing between pieces of charcoal and makes sure that the fire "settles" at the right rate as everything burns down.

 

As others have mentioned, air and temperature control are your likely problems here. It's somewhat counterintuitive, but I have found that (to a point) more air = more carbon, at least for this setup. My best guess is that a higher air flow causes the hot-spot to be bigger so the material spends more time in a liquid/near-liquid state picking up carbon. Too high and the heat goes almost all the way to the bottom and you get cast iron. 

 

One other important detail which you already noticed is making sure the bottom of the furnace is hot enough. You need to slowly build up the fire from the bottom up. I like to start with a few inches of charcoal and a low air blast and wait until it is all burning, then repeat with a few more additions, gradually increasing the air. If you don't have enough heat low down in the beginning, the puck will settle too high in the furnace where the air blast will oxidize it and turn it into a foam, which looks a lot like what you have. I have found that when this happens you can't really make anything from the melt, not even wrought iron, since if has too much oxide in it to consolidate. 

 

Hope this helps!

[Kreg Whitehead]

Thank you sir!! Soooo I got the cowboy charcoal from tractor supply and I did not cut any of it.

They had royal oak at smiths yesterday....I will give that a go.

I am going for round 2 today....and I will try and use this and what I think I learned last time.

Also I take back the part about yoda being heavier than what I put in.....12 lengths of these framing nails have more weight to them than I would have imagined.

Maybe my kid can help me with the vid this time around also.

[Kreg Whitehead]

Gosh......I think I did it. Now I have to do something with it. lol

Let me know what you guys think. I smacked it a half dozen times with a sledge before I took the pic on the sand stone....and it didnt crumble.

Looks like its sparking nicely.....to me at least.

It was about 10 sticks of framing nails and a pretty good little nugget of wagon that I couldnt resist tossing in in the middle of it all.

 

Edited April 30 by Kreg Whitehead

[Alan Longmire]

Success!  Now what are you gonna do with it? 

[Kreg Whitehead]

I bought a 32ton jack a couple months ago.....this has been in my car for weeks to take it to a real welder.

I have a guy lined up but have been too lazy to drive a couple hours.

I was thinking crucible was gonna be next but this stuff seems pretty consolidated for the most part.

 

[Joshua States]

That looks good Kreg! you might want to try forging some of those pieces flat, stacking them and forge welding them together to start the consolidation process.

That's basically what I did when I used nails in this process. After that I made square bars.

[Will Robertson]

Thank you very much to all the folk contributing to this. This is way beyond what I can do at the moment but it's interesting for me to read and learn.

One thing that might help is that I've found that it's possible to buy good quality alumina crucibles - sometimes with lids - and crucibles made from a mixture of graphite and silicon carbide on eBay - getting a good quality supplier can take trial and error but does seem to be possible. I don't know if melting iron in a crucible - possibly with flux - as an alternative to melting it in contact with the charcoal?

Having said that, I know that the iron and steel industry uses special refractory materials that can resist being attacked by the alkaline fluxes used and I'm not sure how long the above would last...

[Kreg Whitehead]

5 hours ago, Will Robertson said:

Thank you very much to all the folk contributing to this. This is way beyond what I can do at the moment but it's interesting for me to read and learn.

One thing that might help is that I've found that it's possible to buy good quality alumina crucibles - sometimes with lids - and crucibles made from a mixture of graphite and silicon carbide on eBay - getting a good quality supplier can take trial and error but does seem to be possible. I don't know if melting iron in a crucible - possibly with flux - as an alternative to melting it in contact with the charcoal?

Having said that, I know that the iron and steel industry uses special refractory materials that can resist being attacked by the alkaline fluxes used and I'm not sure how long the above would last...

Facebook is always tossing the vids my way from some one that goes by FZknives.....and his "wootz" steel blades.

In a nutshell he use's these small one time use crucibles....that last one he broke up box cutter blades...then added what appeared to be some powdered steel,blacksand,and crushed glass.

The ingot is maybe 1 inch dia. x 3" length and he just busts the crucible off of it.

I am not having any luck finding anything like that.

Like I said before.....I am kinda shocked this thing is as solid as it is.

Time to put project press back on the front burner.

[Will Robertson]

On 5/1/2023 at 4:29 PM, Kreg Whitehead said:

Facebook is always tossing the vids my way from some one that goes by FZknives.....and his "wootz" steel blades.

In a nutshell he use's these small one time use crucibles....that last one he broke up box cutter blades...then added what appeared to be some powdered steel,blacksand,and crushed glass.

The ingot is maybe 1 inch dia. x 3" length and he just busts the crucible off of it.

I am not having any luck finding anything like that.

Like I said before.....I am kinda shocked this thing is as solid as it is.

Time to put project press back on the front burner.

Black sand and crushed glass seems a kind-of odd choice of flux - I think the iron and steel industry uses lime (impure calcium carbonate) - which will decompose to calcium oxide at steel making temperatures - though folk with better knowledge of the industry might know much more detail than that.

I find small crucibles on eBay by searching for "alumina crucible" or "graphite crucible" - sometimes a lot of searching is needed to find the larger ones though. I don't have a clue whether graphite or a mix of graphite and SiC survives steel melting temperatures - that's beyond my knowledge unfortunately.

[Gerhard Gerber]

On 5/1/2023 at 4:29 PM, Kreg Whitehead said:

Facebook is always tossing the vids my way from some one that goes by FZknives.....and his "wootz" steel blades.

In a nutshell he use's these small one time use crucibles....that last one he broke up box cutter blades...then added what appeared to be some powdered steel,blacksand,and crushed glass.

The ingot is maybe 1 inch dia. x 3" length and he just busts the crucible off of it.

I am not having any luck finding anything like that.

Like I said before.....I am kinda shocked this thing is as solid as it is.

Time to put project press back on the front burner.

He's got a YT channel, not sure if there is any metallic object he hasn't used to make crucible steel

[Alan Longmire]

2 hours ago, Will Robertson said:

Black sand and crushed glass seems a kind-of odd choice of flux

 

The black sand is magnetite, which reduces to iron, and, if carbon is present, becomes steel.  The glass is not a flux per se, it is just an oxygen barrier that floats on top of the liquid steel.  

 

There's very little use for lime in small-scale homemade steel production.  If you're after cast iron, or if you have a particularly refractory ore like titaniferous magnetite, a handful or two during a short-stack bloomery smelt will help the slag run, but otherwise it's not much use at the scale we tend to work.  The goethite/limonite ores most of us like to play with are naturally rich in silica and are self-fluxing when smelted.  Hearth melts (like the title post here) start with iron or steel and simply remelt it through a reduction zone in charcoal to make a higher carbon steel than the feedstock.  The slag that develops there is from the ash.  

 

Crucibles make things weird. You can do an open crucible reduction from ore and charcoal to create steel, but that's not easy.  Most people are trying to make Wootz or its analogues, which start with cast iron and some organic material.  Traditionally this was done in a sealed crucible, but adding the glass serves the same purpose.  A few people even use a little modern tech when making crucible steel, such as adding a bit of aluminium at the end of the melt to degas the steel. 

 

Lots of ways to make small quantities of steel of varying carbon content at home.  If you want to start making freaky alloys using rare earth elements, then you need to go to the thermite reaction.  Note that is not for the faint of heart or those with neighbors who are easily concerned by blinding light and clouds of sparks!  Or the occasional BOOM! if you get the mixture wrong.  

 

The hearth method Kreg is doing is a rediscovery of an old Norse technique first written down by Ole Evenstadt in the 1700s. It bypasses the usual cementation/carburization method of making shear steel, which is a nice thing if you're low on resources and need a small amount of steel fast.  Plus it's fun to do!

[Joshua States]

5 hours ago, Will Robertson said:

I don't have a clue whether graphite or a mix of graphite and SiC survives steel melting temperatures - that's beyond my knowledge unfortunately.

Most of the guys making Wootz are using these: https://pmcsupplies.com/casting-supplies/crucibles/salamander-crucibles in A4, A5, or A6 sizes depending on the size of their furnace. With careful preparation, you will do only minor damage to the crucible and get 4-6 melts out of a single crucible.

[Kreg Whitehead]

I chopped it in half again. I am surprised how homogenous it is for a bunch in individual nails.

I am curious as to what if any pattern I will see once I press one on these into something that resembles a knife.

I tried to heat treat and etch the smallest piece in this pic...but didnt see any pattern nor did it really skate a file well.

Maybe was just too thick and or oil was too slow.

[Will Robertson]

19 hours ago, Alan Longmire said:

 

The black sand is magnetite, which reduces to iron, and, if carbon is present, becomes steel.  The glass is not a flux per se, it is just an oxygen barrier that floats on top of the liquid steel.  

 

There's very little use for lime in small-scale homemade steel production.  If you're after cast iron, or if you have a particularly refractory ore like titaniferous magnetite, a handful or two during a short-stack bloomery smelt will help the slag run, but otherwise it's not much use at the scale we tend to work.  The goethite/limonite ores most of us like to play with are naturally rich in silica and are self-fluxing when smelted.  Hearth melts (like the title post here) start with iron or steel and simply remelt it through a reduction zone in charcoal to make a higher carbon steel than the feedstock.  The slag that develops there is from the ash.  

 

Crucibles make things weird. You can do an open crucible reduction from ore and charcoal to create steel, but that's not easy.  Most people are trying to make Wootz or its analogues, which start with cast iron and some organic material.  Traditionally this was done in a sealed crucible, but adding the glass serves the same purpose.  A few people even use a little modern tech when making crucible steel, such as adding a bit of aluminium at the end of the melt to degas the steel. 

 

Lots of ways to make small quantities of steel of varying carbon content at home.  If you want to start making freaky alloys using rare earth elements, then you need to go to the thermite reaction.  Note that is not for the faint of heart or those with neighbors who are easily concerned by blinding light and clouds of sparks!  Or the occasional BOOM! if you get the mixture wrong.  

 

The hearth method Kreg is doing is a rediscovery of an old Norse technique first written down by Ole Evenstadt in the 1700s. It bypasses the usual cementation/carburization method of making shear steel, which is a nice thing if you're low on resources and need a small amount of steel fast.  Plus it's fun to do!

Thank you very much - I hadn't realized that "black sand" meant magnetite - that makes sense now.

I can understand the role of the glass now in floating to the top and sealing out the oxygen. If it's of any help to anyone, there are different glasses melting at different temperatures - not sure if that would be of any help here or not.

>There's very little use for lime in small-scale homemade steel production.

Thanks - it's interesting for me to know that difference between home and industrial production.

 

>The goethite/limonite ores most of us like to play with are naturally rich in silica and are self-fluxing when smelted

 

Thanks - that's also interesting for me to know. (If anyone is looking for a cheap and plentiful supply of silica for other ores the clear silica cat sand is one and fine silica sand provided to potters and glass artists for mould making is another.)

>thermite reaction

"lead me not into temptation..." thermite reactions are great fun and I think I may be able to grind down aluminium to small enough particles using a ball mill but I don't reckon I have the knowledge at the moment to do this. I'd have to do it after wet weather to avoid the risk of setting fire to the entire mountainside if it got more lively than expected... I'm in the fire service here...

>If you want to start making freaky alloys using rare earth elements

What are the advantages and disadvantages of alloys involving rare earths?

>The hearth method Kreg is doing is a rediscovery of an old Norse technique first written down by Ole Evenstadt in the 1700s. It bypasses the usual cementation/carburization method of making shear steel, which is a nice thing if you're low on resources and need a small amount of steel fast.  Plus it's fun to do!

That's interesting - fairly advanced steel making in Scandinavia in the 1700s...
 

[Will Robertson]

17 hours ago, Joshua States said:

Most of the guys making Wootz are using these: https://pmcsupplies.com/casting-supplies/crucibles/salamander-crucibles in A4, A5, or A6 sizes depending on the size of their furnace. With careful preparation, you will do only minor damage to the crucible and get 4-6 melts out of a single crucible.

Thanks - that's interesting to know that these can survive multiple melts.

[Alan Longmire]

1 hour ago, Will Robertson said:

different glasses

 

Most folks use ordinary green bottle glass.  One smith I know swears by Heineken bottles.  He says that green has trace amounts of vanadium, which assists inb getting the chemistry right if you're making a certain type of Wootz.

 

1 hour ago, Will Robertson said:

What are the advantages and disadvantages of alloys involving rare earths?

 

They tend to be strong carbide formers and can help with grain size during heat treatment.  One of our former members here even patented a process of adding rhenium (not a rare earth, I know...) to steel via thermite.  Erbium will alloy with vanadium and other carbide formers to increase their ductility, so you get a combination of the fine grain imparted by vanadium with higher toughness at a given hardness.  I don't know of any commercial alloys that do this, it's just fun theoretical stuff.  The only commercial Lanthanide rare earth steel alloys I know of are super-magnets and some used in the nuclear industry, because they tend to be really good at absorbing neutrons.  In the Actinide series, thorium is used to improve the life of TiG electrodes.  It's also the only actinide that's relatively safe enough to use unshielded, as its radioactivity isn't particularly strong and is limited to alpha particles.  

 

So, not as useful in blade steel as they are in glass, but since their melting points tend to be extremely high, thermite is one of the better ways to add them at a small scale.  

 

Edit: Oh yeah, the late Jock Dempsey proposed using a cerium oxide edge on stage combat swords, since it sparks so impressively.  So there's that... 

[Jerrod Miller]

Here is a paper about rare earth elements used for grain refinement I just so happened to run across today while looking for something else.  

 Rare_Earth_Grain_Refiner_Addition_Methods.pdf

[Alan Longmire]

I was hoping you'd check in on this before it got too speculative.  . I'm riding the ragged edge of limited knowledge on that last post!

[Jerrod Miller]

32 minutes ago, Alan Longmire said:

I was hoping you'd check in on this before it got too speculative.

I read all posts on this subforum, as well as Hot Work, Beginners Place, Tools and Toolmaking, Metallurgy and other enigmas, Heat Treating by Alloy, and a few others, and many of the posts in other subforms that I don't read everything in.  I chime in whenever I have something I feel should be added, but you and a few others often beat me to the punch and I have little to add these days.  

[Aiden CC]

On 5/3/2023 at 3:25 PM, Kreg Whitehead said:

I chopped it in half again. I am surprised how homogenous it is for a bunch in individual nails.

I am curious as to what if any pattern I will see once I press one on these into something that resembles a knife.

I tried to heat treat and etch the smallest piece in this pic...but didnt see any pattern nor did it really skate a file well.

Maybe was just too thick and or oil was too slow.

This could also be a due to inhomogeneity of the puck, which I have often experienced in my own re-melts. If the puck doesn't settle low enough in the fire, I have found it leads to a well carburized top and under carburized bottom, potentially having to do with the amount of time material charged at different times was able to be a liquid or "slush" in a part of the fire where it could pick up carbon. I would recommend grinding a flat surface and carefully comparing the sparks from different parts around the edge as well as how that whole surface sparks. Every once in a while I still get material that averages out to be 0.4-0.5% C from a high carbon and low carbon layer, which I use for cladding around a higher carbon core for swords, etc. (though looking at metallographic analyses of a number of medieval knives, the edges were often in that range and actually quite soft by modern standards!). I use either water or a fast oil (Parks 50 for me) depending on the blade geometry, though admittedly I always quench swords in water because I don't have a large tank with oil.

[Kreg Whitehead]

The two larger pieces I cut in half with a chop saw and wheel.

And yes it took forever. lol 

It seems to spark great all the way through.....althouh I dont think it was sparking as crazy high like the first scratch I put a pic up of.

That sparked way better than any store bought steel I have ever had.

Here is a pic moments before I pulled the puck

It was on the bottom and kind of stacking up on the side tword the tuyere sp?

Kinda makes me go back to wanting to crucible this again.