Smelting wootz

Victor Creazzi

King of Bondo
So the ingot is forged into a bar. In your experience, is the bar all of the same properties throughout, or do you find variance in the material?
 

Bruno

Administrator
Staff member
In the ingots I've turned into bars (and the bars I've used before) it's similar throughout. Although logically, the middle of the bar would be a bit more streached out because it's more material drawn out but it's not that noticeable and perhaps the pattern is slightly more pronounced on the outside of the ingot. There's no significant difference I could see.

That said, it depends on the smelter and the process used. I've seen plenty of bars at knifeshows that had crunchy bits in them from material that hadn't mixed properly. And I've been told that sometimes if the smelting didn't go right, you might get a low carbon 'dead spot' or a cold shut. I did find a cold shut once, during grinding.

I was told by Niko to first flatten the ingot to a pancake, and then draw it out again. He told me this creates a lot more distortion and lengthening, compared to going straight to a bar shape. That makes sense imo. I recently saw someone punch a hole through an ingot, cut it, and then pry it open like you would straighten a piece of coil spring. You'd get the same length of drawn bar, but the pattern would hardly be stretched at all because you fold the ingot open instead of drawing it.
 
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Victor Creazzi

King of Bondo
A local who is trying to bloom wrought iron from local magnetite has contacted our local smithing group for advice. I'm planning on going to see his set up and possibly help him with some tooling in a couple of weeks. Anyone know anything about a bloomery for wrought iron? He has tried a few times and come close, but he thinks he should get better blooms.
 

Bruno

Administrator
Staff member
@Mike Blue would be the first to come to mind.
You could also contact Wayne Potratz he is also an expert. You can find him in my friends list on FB he is a really friendly guy.
 

Bruno

Administrator
Staff member
I'm getting some more experience with niko's wootz. It helps a lot that we can talk as friends about the chemistry and the influence of forging techniques and temperature.

I'm pretty happy with it. Especially given the fact that it was what i expected:D

2020
 

Jfk742

New Member
That looks gorgeous. Really well defined. Is his wootz more defined than Pendray wootz you had used in other razors? At least I remember it as Pendray’s but I may be mistaken.
 

Bruno

Administrator
Staff member
2 carbon steel and 1 stainless.
Stainless is a bear to forge according to Niko. And I do believe him. It should be wonderful for kitchen knives. I have some beautiful pieces of narhwal I want to use for a chef knife for myself but Ideally they will be stainless.

Additionally, last week I had a visitor who is a retired CEO / foodie and he really liked what I was doing. Bought a wootz kitchen knife and was already thinking about which chefs he was going to show it to. Things are lining up to declare 2022 my wootz year :)

2025
 

verndahl

AKA tintin
I understand very little about metalurgy (let alone the making of wootz) but can you give me a brief "wootz for idiots" explanation of how you get stainless wootz? (Since i assume the original wasn't stainless)
 

Bruno

Administrator
Staff member
I understand very little about metalurgy (let alone the making of wootz) but can you give me a brief "wootz for idiots" explanation of how you get stainless wootz? (Since i assume the original wasn't stainless)
Very simple actually. You add 18% of Chromium to the mix and do more or less the same thing.
During solidification, you get the same cementite dendrite structures. The Chromium makes the surrounding steel stainless.
The biggest difference is the forging temperatures are a bit higher, and more importantly the steel is very tough to move.
I'll have to check the details with Niko but in a nutshell I think it's like this: Stainless steel austenizes at a much higher temperature. Around 1050 celsius. At that temperature, you get the mimumum amount of carbon in the steel, and the remainder goes into the wootz carbides. But at 1050 it's also going to be a bitch to move because 1050 really isn't that hot for this kind of work. I work damascus much hotter.

But if I work wootz much hotter, the carbon is going to go into the steel, where in this case it will also make chromium carbides which distract from the pattern, as well as make the steel more fragile. I may work the ingot into a thick bar like above, using my press. At that point there is enough heat inside the bar to make it move a bit. But beyond that I think I am going to have to visit a local friend with a 170 lb powerhammer because a press is really the wrong tool for working a thick bar down to knife thickness. The steel loses heat between those dies so quickly that it really doesn't move, and might crack.
 
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