Wootz Makers and Production Methods

[Tim Mitchell]

Jan,

Thanks for the name, I can't find any info for a Kutoven in this forum or anywhere on the web connected with wootz. Could you see if you can get some more info, like his full name?

 

Marcus,

No worries as we say over here I like having good information available to help people experiment in wootz and perhaps make fewer mistakes and more discoveries.... with less pain. This all looks easy on paper, but even if you do it all right you can still get failures for no explainable reason and a lot of the success comes from experience and a feel that you get, knowing how to work the metal as it changes.

 

I checked out your proposed method, I wish you well with it. Let us know how it goes. One thing to remember is that if you get above 2% carbon, it ceases to be Wootz / Pulad / Bulat. It also ceases to be steel according to the definition of steel. You may have a forgeable cast iron which works well, (I would be surprised if you did) but it isn't wootz, it would be something different. Also you may have surprises as theory usually falls flat with practice in the real world, you may have to adjust your ingredients several times before you get your desired quality of ingot. Very few hit it first time around. You may want to use something a bit larger than a hair dryer too, and find a ceramic end for your pipe or you will melt it before you melt the crucible.... All the best and happy experimenting.

 

Your method sounds interesting and reminds me a bit of what Aristotle did back in the 4th century BC when he was making crucible steel. It is the earliest known recipe for patterned crucible steel. It is in the paper which is linked with Niko's method in this thread.

 

Tim.

[Jan Ysselstein]

Tim,

 

This definition of Wootz, where is it stated "if you get above 2% carbon, it ceases to be Wootz / Pulad / Bulat" ? I have read about a blade not being studied as wootz because it was hypoeutectoid, but have never read about limitations at the higher end.

 

Jan

Edited February 25, 2015 by Jan Ysselstein

[J_Martin]

It seems to me that many PhD's and metallurgists are trying to say it's impossible to make "True Wootz" today. We can only call it modern perspective wootz (Greg Orbach in pinned Bloomers and Buttons section "What is Wootz? 2006)

I can't seem to paste anything or link to it. ?

[Tim Mitchell]

Hi Jan,

The limitation at above 2% is that steel ceases to be steel at above 2% Carbon, it becomes cast iron and you have to remove carbon through decarburisation to make the ingot carbon level lower and able to be forged. This is what was done in southern india according to some accounts. Ingots that are above 2% are basically unforgeable without reducing their carbon content, that is why the highest carbon steel blade that has been examined from ancient times has 2% carbon. For most wootz makers it is safer to aim for 1.5 - 1.6% carbon, any higher than that means you are increasing your chance of getting an unforgeable ingot.


J_Martin,

There are some who are saying that it is impossible to make True Wootz today, but that is simply a scholarly smokescreen. By suggesting modern perspective wootz I think Greg was trying to avoid the debate which can get pretty hot... he wasn't saying that the ancient methods and patterns haven't been reproduced today.... he has done it himself.

There is no single "wootz process" of melting or smelting ingots, there is no single forging method. We can't say exactly how the steel was forged out in the old days, we know next to nothing about the methods of the ancients. We have very few accounts and some educated guesses from scholars. Some of the accounts are informative but often lacking precise details. They are also subjective and only as reliable as the expertise of the person giving the account.

We have to remember that the first reported watered pattern crucible steel maker was Aristotle back in the 4th century BC, it has been made over 2000 years and over thousands of miles with different methods of melting or smelting and using different methods of forging out ingots. It has been forged by smiths over thousands of miles from the Vikings to the Chinese. Anosov came up with four different methods of making ingots that are all historical methods there may be more, but that is just what we know.  These are the basic four:

1. (Direct reduction) from ore with charcoal.
2. (Co-fusion) of cast iron with bloom iron.
3. (Decarburisation) of liquid cast iron until it becomes solid.
4. (Carburisation) using bloomery iron and a carbon source.

 

Some also include casting molten steel into a mold but I have yet to see evidence for that method, it was mistakenly suggested by Abbott in the early 1800s.

Traditionally we are told that Wootz, by that name, came from Southern India and Shrilanka only. Simply that is because Ukku / Wootz / Hinduwani are the local words that were used to describe it. We are told that the ingots from Northern India and Central Asia were called Pulad / Bulat / Damascus etc. which was because it was predominately a Persian controlled method, but even the Pulad methods changed over 1000 years and over different locations.  (edit: it has now been shown that the word Wootz came from the word Utsa which was used in Bombay to describe the cakes of steel)

If you make steel ingots by one of the processes Anasov listed (which is what all makers are doing) then the ingots are Wootz or Pulad/Bulat. You then can take that ingot and forge it out any way you wish and it still is Wootz / Pulad. It will be either a high quality blade or a low quality blade, but the pattern doesn't make it Wootz / Pulad, it is how the ingot was made, ie. in a crucible with a specific carbon content, either smelted or melted or carburised etc. This being said there are patterns that traditionally came from different regions.

There is a difference with the patterns and debating if we are able to reproduce the ancient patterns exactly, this is what most "true wootz" people are talking about. The truth is that we are able to macroscopically and microscopically create patterns in Wootz / Pulad ingots that are identical to the old patterns. There are only a handful of makers though who are able to produce some of the traditional patterns and it is to do with their method of forging and the temperatures that they forge at (and impurities of specific minerals). Contemporary reports say that Anosov was able to make blade patterns identical to the traditional blades (and better quality), Al Pendray has, I have, Niko and Greg and Jeff and quite a few others have been able to create patterns basically identical to the original patterns. Some makers can only do one pattern, others can do several of the ancient patterns. Those who say that the modern patterns are not true Wootz or true Pulad are usually not aware of the facts.

There are two things that confuse the matter these days and that is that modern makers follow the European tradition of calling all crucible steel Wootz when traditionally it was called different names depending on where it was made and that meant a slightly different process was used at those locations (and different quality some report). Modern methods generally use a mix of "Wootz methods" and "Pulad methods" this leads some to say that it isn't true Wootz. However this mix is what happened in Hyderabad and it is clear to me that over time the ingot production methods changed at a single location and makers would have changed their methods for various reasons. 1000 years is a long time and nothing stays the same.

So it is my opinion and the opinion of Ann Feuerbach that Wootz and Pulad patterns have been replicated since the 1800s and are being replicated today. The only debate is over whether a pattern is traditionally a Pulad or a Wootz pattern, and whether the ingots are from Wootz method or Pulad method or an unknown ancient mix of methods..... in other words it is a discussion of historical definitions.... but I am happy if people call their steel Wootz.

Edited May 12, 2022 by Tim Mitchell
Correct error.

[Tim Mitchell]

One other thing about the historical accounts: we are assuming that the methods that were given in the accounts were the standard methods used at that location. We assume that only one method was used all the time, we assume that the person giving the account was able to accurately determine the colour of the steel being worked, we assume that they were working a specific %cabon ingot (different % carbon ingots require different colours of forging temp) , we assume that the colours observed were in the shade not in open sunlight. This is why I say that some of the accounts can be misleading. We can make educated guesses at best and often the only way of working out exactly what they were doing as far as forging is to do experimental archaeology and find out under what conditions these patterns appear and then we have an idea of what they may have been doing back then. These ancient smiths did not forge their ingots at a specific temperature, they had no way of determining the exact carbon content (spark test was all they had), they would have forged according to feel and then colour. These are things that cannot be reported precisely and so we have to try a whole range of different temperatures and methods to see which one creates what the ancients created. We add to this our understanding of metallurgy and we can then get close to describing exactly what is happening in the steel and what the ancient smiths were probably doing. Anyway those are my thoughts...

Edited February 26, 2015 by Tim Mitchell

[ZebDeming]

"but the pattern doesn't make it Wootz / Pulad, it is the process of how the ingot was made. "

So by this account, propane furnaces and modern refractory don't make "Wootz"? Like I said before I've only dabbled in making crucible steel, but I have made quite a bit of bloomery material, there is always the thought of trying to make it more "authentic", I've taken the thought process as far as wanting to do everything just the same as it was before, but it presents a few problems, sure I could use bellows, but were they made from wood hewed using an axe made of bloom, was the leather tanned as they did, etc.. Was the shovel I use to dig the ore made of bloom.. The hammer, tongs, anvil... You can see where I'm going with this, everything we do in historical metals is a reproduction if we want to call it by historical terms. We aren't in the time and place when it was made, and we won't be, so where is the line drawn?

[J_Martin]

So, your saying we can't make anything made in ancient times unless we wear skins and live in tents? Or, at least, we can't call it by the same name. What makes the difference of the heat source or the fuel or the crucible? We are trying to reproduce the chemistry and patterns.

I am not being sarcastic or facetious, I'm simply asking some questions.

[Tim Mitchell]

You misunderstand me, I am saying the opposite, I am saying that there were so many methods "processes" and under the name wootz and various methods under the name of Pulad. There were four different methods of making ingots and different designs of ovens, different types of iron from ore to cast iron. We have crucible steel when we melt or smelt iron in a crucible that comes out with a specific range of carbon in it that is representative of the ancient blades. It is called pulad by some if it is slow cooled and wootz if it is fast cooled.... by some definitions. It is so hard to say that something is not wootz. The method of heating is basically immaterial, except it seems that inductance does not create a pattern in ingots.... That is all I am saying... it is the same stuff as the ancients produced no matter what you call it. Wootz has in the last 150 years become the European word that has been used to describe both varieties, whether it is correct or not that is what they refer to it as. It is some scholars that are trying to be so specific, not me, I don't really agree with being that specific.

 

If we want to call certain patterns more Pulad style or more Wootz style then that is fine, I have no problem with that, but it is still the same stuff that the ancients produced. Hope that is clearer.

Edited February 26, 2015 by Tim Mitchell

[Jan Ysselstein]

Tim,

" The limitation at above 2% is that steel ceases to be steel at above 2% Carbon, it becomes cast iron and you have to remove carbon through decarburisation to make the ingot carbon level lower and able to be forged. This is what was done in southern india according to some accounts. Ingots that are above 2% are basically unforgeable without reducing their carbon content, that is why the highest carbon steel blade that has been examined from ancient times has 2% carbon. For most wootz makers it is safer to aim for 1.5 - 1.6% carbon, any higher than that means you are increasing your chance of getting an unforgeable ingot. "

 

My personal experience with cast iron tells me it can be forged..at times, I must have forged cast iron, well over 3% carbon...here is a pic of the carbides in a forged bar of cast iron.

 

 

 

Regarding all the above dialogue...you are so good at summarizing the methods , why not use that here as well. Big paragraphs are a challenge to me .....but I love pictures.

 

Jan

Edited December 20, 2017 by Jan Ysselstein
Privacy

[Tim Mitchell]

You are correct that you can forge cast iron and even forge weld it to a certain extent, but it doesn't mean it is steel and it is much more brittle. Metalurgists only call metal below 2%C steel and the wootz blades from history are all 2% and below as far as I have seen.

 

I will try to summarize my comments when I get a few minutes to spare, sorry to be a bit long winded... and thanks for being a mate and telling me

[Tim Mitchell]

Ok Jan, here is the summary as requested…. Hope it is simple enough....

Concerning Carbon in ingots:

- Some ingots were above 2%Carbon Ann says they were decarburised to fall below 2% for sale and forging (Southern Indian process)
- Steel by definition is 2% Carbon and below, Cast Iron is above 2% (cast iron can be forgeable, just brittle and hard to forge)

Concerning the Wootz or not Wootz argument:

- Pulad/ Bulat is what the crucible steel was called in Central Asia and Northern India (evidence for predominately slow cooling of ingots)
- Wootz / Ukku is what the steel was called in Southern India and Shrilanka (and many other local names) (evidence for predominately fast cooling of ingots)
- It seems that the Europeans started to call all crucible steel Wootz in the 1800s and the name has been correctly or incorrectly used ever since to describe Crucible Steel.
- Both were made in crucibles using different methods, sometimes a combination of methods
- There are four basic methods to make crucible steel ingots, all modern smiths use one of these traditional methods in various degrees.
- The type of furnace does not determine if it is Wootz or not
- The method of forging does not determine if it is Wootz or not
- We have very little known information about methods of forging from the ancient days.
- It seems some patterns were more associated with Wootz, other patterns were associated with Pulad (Pulad was generally larger in pattern) But moreso the patterns were more associated with locations that forged out those patterns.
- There were many ways of forging to get different patterns and many different ways to get ingots over the 2000 years it was made.
- If someone was to say that only one method of making ingots or of making blades is Wootz or Pulad that would not be correct historically as methods and ingredients changed over time and location.

Concerning Wootz / Pulad not being reproduced by modern makers:

- There was great variation in the composition of ancient ingots (different ores, different sources and methods of adding carbon etc)
- There is variation in the chemical composition of modern ingots
- The patterns by some modern smiths match the old patterns as identically as you can get
- Anosov replicated the best ancient patterns in the 1800s perfectly according to Colonel Abbott.
- A select number of smiths today are able to make blades that are equivalent to the ancient blades.

- We have not reproduced all the old patterns, but some have been reproduced

Concerning first hand accounts of ancient methods:

- There are some good historical accounts we just have to be careful not to make assumptions about the account
- People assume that the forging and annealing colours etc were observed in dim light, not daylight (daylight changes the colour as viewed especially to an amateur)
- We should not assume that the method described was the only method used at that location over hundreds of years
- We should not assume that the ingot %C was a specific level (different %C ingots require different colours of forging to get carbides to move ie. Acm moves)
- Unfortunately the available accounts don't tell us a lot of concrete information
- We have a tiny tiny fraction of accounts of how smiths forged ingots or made ingots.
- We know almost nothing of the methods of smiths forging out ingots exported to regions from Scandinavia to China
- Debating that one method as described is the only method that is Wootz or Pulad (with all these unknowns) is not logical.

 

There are good researchers out there, but just because someone says that wootz has not been recreated to match the old blades, just means that they haven't looked at all the evidence.

 

Edited March 2, 2015 by Tim Mitchell

[ZebDeming]

As far as my comment above, personally I feel that modern reproductions are the same as historical metals, but the way we get them can be very far from original methods. There are a few makers of bloomery iron that are as authentic as it ever could have been. I was more concerned about Tim's comment about determining how the product was made to give it a name, and I misunderstood what he was trying to say. Modern methods can produce historical metals, but still they are a reproduction, just as my next bloom will be a reproduction of my last. I won't muddy the waters here any longer, I'm sorry if I misunderstood you Tim

Zeb

[J_Martin]

Thank You! I'm sure the discussion will continue, it's been going on for a few hundred years already. I think Niko is right, the only way to learn wootz is from making wootz. Not an exact quote.

[Jan Ysselstein]

Tim,

 

Thank you for doing that..it makes the thoughts much clearer to me. I do not agree with many of your statements...and do not want to get into it right now, as some of the topics lead to subjective means. I will just continue with my other thread and lay it out as clearly as I can....what falls between the lines will be obvious to those familiar with steel metallurgy.

Jan

Edited February 26, 2015 by Jan Ysselstein

[Tim Mitchell]

No worries Jan, it is a complex subject historically and metallurgically, I see lots of debate and different opinions for many years to come. So long as we keep working at just making the steel, it is all ok. I look forward to seeing what you come up with in the future.

[Tim Mitchell]

Here is the method / methods used by Greg Obach. Thanks Greg for sharing your method and thoughts on making wootz!

 

The first method listed is the one that was published by Greg during his time in college in 2003. A link to his paper is HERE. It was one of the good early papers of wootz makers that helped lots of people to get a good handle on methods of making wootz when there wasn't a lot of information out there.

His method has changed quite a bit since then (as have all our methods) and it is included here because the paper still has a good amount of information for the beginner, especially on forging technique.

It is good to compare it with the current method that Greg uses, and to realise that the results that he gets now are much better than back then.

 

He cautions about getting the carbon % in the ingot too high as the failure rate, especially for a beginner, increases the higher you go. He really likes a little phosphorous in the mix which makes the pattern stronger. Greg adjusts the melts according to what he has on hand and the different types of charges listed should aid people who find some of the ingredients hard to get in their area.

 

My personal experience is that sticking with one type of charge and perfecting that is a much easier thing for beginners and helps everyone lower their failure rates.

 

GREG OBACH:

2003 Method:

Crucible Charge:
- Charge crucible with 1010 and high quality cast iron (calculated by weight to 1.5% C)
- Cover charge with 1 cup of glass

Firing Stage:
- Place crucible in furnace
- Heat furnace to 1535 °C (40 to 90 minutes)
- Ramp the temperature down slowly to simulate a slow cool (10 - 20 minutes)
- When the charge was solid the burner was shut down
- Leave furnace and crucible to cool overnight
- Remove ingot after 6 hours and chip off glass

Forging Stage:
- Bake ingot in iron oxide scale at 1100°C for 5- 10 hours to decarburise the outer layer of ingot and to form a finer microstructure
- Carefully forge ingot below Acm and above A1 on the carbon phase diagram
- Draw out ingot to a bar shape
- Forge out blade making sure the steel is forged evenly on both sides and only while it is hottest to avoid warpage.

Heat Treating Stage:
- Heat blade until nonmagnetic and quench in light warm oil
- Clean off surface of blade until bare steel is exposed.
- Temper the blade at 350°F until yellow brown
- Draw a purple or blue temper over the tang of the blade to make it less prone to breakage


2015 Method:

Crucible Charge:
- Charge is calculated to 1.5 - 1.6 % carbon by weight (higher is risky for a beginner with higher failure rate)
- Likes to have a bit of Phosphorous content in the wrought iron to add strength of patterning
- Likes to add some ferric Vanadium to the mix or Fero Moly

Uses different charges:
Type 1:
- Charge crucible with a mix of cast iron / pig iron, and mild iron plate (sorel pig iron is best)
- Cover with green glass flux layer
- Leave crucible open

Type 2:
- Charge with wrought iron chain, a little ferric Vanadium and crushed graphite calculated to correct carbon percentage by weight.
- Cover with green glass flux layer
- Crucible is closed

Type 3:
- Charge with wrought Iron chain, ferric Vanadium and pig iron
- Cover with green glass flux layer
- Crucible is closed

Type 4:
- Charge with W1, pig iron and ferric vanadium,
- Cover with green glass flux layer
- Closed crucible
- This is the easiest method.


Roasting / Annealing stage:
- When furnace is at a dull red place ingots from last firing in furnace and seal the furnace, allow to cool overnight (increases forging success)
- Fire furnace at 1600°C approx or slightly less, once the furnace is hot the charge melts in 15-20 minutes, cooler furnace takes longer, melted charge is verified visually.

Forging Stage:
- Forge just above Acm
- Forge on both sides, continue until ingot is reduced to a bar.
- Uses plenty of fullering and surface grinding and deformation
- Continue forging below Acm
- Brush scale off bar during each forge cycle
- Forge blade as close to shape as possible

Heat Treating Stage:
- Heat blade until nonmagnetic and quench in light warm oil
- Clean off surface of blade until bare steel is exposed.
- Temper the blade at 350°F until yellow brown
- Draw a purple or blue temper over the tang of the blade to make it less prone to breakage

Edited May 12, 2015 by Tim Mitchell

[Tim Mitchell]

Well the presentation was a success, however Murphy was lurking around the corner with the Wootz melt and later forging. It was very educational for all involved and seemed to be enjoyed by the attendees at the symposium. I would like to share a few thoughts about temperature measurement which will hopefully be of help to others.

 

I normally rely on a high temperature thermocouple attached to a multimeter to monitor the temperature in the furnace during the melt stage, but I was left without a working thermocouple for this demonstration... So I tried to do the dip method which I had never used before.. a few emergency calls to Ric for advice, (thanks Ric!) and I was halfway there.

 

Here are the lessons that I learned. When using the dip method to determine the correct temperature of the melt, you need to use a 4mm to 6mm diameter mild steel or low carbon steel rod with a good bit of length (4 ft at least). Be careful to have the tip rounded and probe the mix in the crucible very gently avoiding pushing the rod into the side of the crucible. The crucibles are very soft at this temperature and gouging a hole in the side of the crucible is a very real possibility.

 

The flux will feel like runny toffee when pushing the rod through it, you are wanting to feel the molten state of the metal below the flux. Don't keep the probe in for any longer than 7-10 seconds or you will have the probe melting.

 

When the charge is mostly unmelted you will feel the molten toffee-like glass on top and then the solid metal ingredients resisting the probe below that.

 

As the charge melts more you will feel the metal starting to soften and then it will feel like thick pea soup with small chopped carrots throughout it. The small chunky bits you feel as you gently stir the mix are the unmelted metal pieces.

 

When the mix is fully molten you will feel a very liquid water like metal mixture under the flux with no resistance to the probe.

 

Once this stage is reached, let the molten mix rest at temperature for about 15 minutes to allow any impurities that you pushed into the molten metal to float out. Then turn the furnace off, or remove the crucible.

 

You can add a spoonful of shell, calcium or a tiny section (1-8th section of a soft-drink pull-tab) of aluminium which helps to absorb excess gasses in the steel. This cuts down on porosity in the final ingot and also bubbles.

 

I had one ingot that got too hot and the oxygen in the melt turned to carbon monoxide bubbles... I will post a pic down the road, it was a pretty bit of art... forget it for knives though.

 

My lesson was don't rely solely on technology, learn the old methods and you will have something to fall back on when all else fails....

 

 

 

Now for the summary:

 

THE DIP METHOD:

 

- Use a 4 ft minimum length, 4-6mm diameter low carbon steel rod with a rounded end

- Keep probe in furnace for less than 10 seconds

- Probe carefully avoiding pushing into or through the crucible side

- Stir mix gently without touching the crucible bottom

- Let mix rest for 15 min after last probing before cooling down

 

Gauging stage of melt

Not melted - Solid under flux

Beginning to melt - Becoming soft under flux

More melted - Chunky Pea soup under flux

Almost melted - Pea soup under flux

Fully melted - Water under flux

Too Hot - Watery and Bubbling like crazy

 

Add a 1/4 inch square piece of aluminum can or a desert spoonful of crushed shell or a bit of Manganese to the melt at the end to absorb gas and reduce bubbling and porosity during cooling. Do this at the point of the last probing and let rest for 15 minutes.

 

Note: Hold the probe just above the flux to let the flux drip off the probe for a second or two before removing the probe. You can hit the probe against the ground and then quench the probe very quickly to remove any further flux and you will have a part of the melt stuck to the probe, this helps to see the state of the mix.

 

 

THERMOCOUPLE COMMENTS:

 

- For the Furnace use a Type B thermocouple protected from the air.

- Use a 1650°C IR Pyrometer to monitor the melt and make sure you calibrate it for emissivity of the object you are measuring

 

- During forging use as a minimum a well shrouded type K thermocouple (cheap but doesn't last long) If you use a type K, use more than one so if one fails you still know your temperature.

- Don't rely on technology alone or you will get bitten every now and then!

Edited May 12, 2015 by Tim Mitchell

[Jokke]

Sorry that I did not reply earlier,

but I have not been on the forum for quite a while.

I am German and learned most of what I did from Achim Wirtz, Anne Feuerbach's PhD and others

still I am in touch with makers in Finnland, being lucky enough to understand Finnish (thx to my wife )

One of the guys you are looking for is Janne K., his nic is/was Kutvonen, he has a site of his own

try him on fb (Jandaus Rahnasto) or here:

http://www.pajauttelu.blogspot.de/p/under-construction.html

you may ask him, if you can put down his real name

 

by the way, Achim told me that a soaking of the king in 720°C for about 12 hours will do a fantastic job on dissolving the C and make it easier to forge it afterwards

I did not try this, yet, but I will on a small cake that I have lying around, sooner or later

 

best regards from Germany

 

Jokke (Lagerspets)

 

PS I have gathered some info on a german forum (messerforum.net as jl-jokke)

http://www.messerforum.net/showthread.php?86118-K%F6nige-backen-oder-Wootzbruzzeln

don't know why, but it has gathered over 50.000 hits

have not been posting much there in the last years

Edited May 30, 2015 by Jokke

[Tim Mitchell]

Hey Jokke, thanks for the link and information, you have some nice steel up there. Lots of hours of doing melts. I was able to look at it using Google Translate and it is pretty readable translating from German.

 

That is interesting about what Achim told you, do you know what range of carbon content that he usually aims for?

 

I also noted that you are doing your melts with one gas bottle. Do you ever use more than one? Do you find the venturi burners to be more efficient with gas than a force fed air burner? You mention that you use 2kg of gas per hour, that seems to be amazing efficiency, how many kg do you use for each melt?

 

Can you share some specifications about the burner that you use, perhaps even a drawing with information for the most efficient burner?

 

Thanks for your input!

 

Tim.

[Jokke]

he aims at 1,5 or 1,6%C as far as I know - rather traditional, but he has made some modern chrome "wootz" , too

this is Achims burner

this is one another friend made for me

I mostly used these two kinds of ventury burners

somwhere I have a pic about how to do one, by a friend,

but I recommend: Gas Burners for forges, furnaces and killns, by Michael Porter

ISBN 978-1-87953520-6 , skipjack press, 2004 www.finneyco.com

to get a better understanding of venturi burners

 

Niko has one that he may give away and I know it works very well

so one could ask him, too

 

never used more than a 11kg gas bottle

one hour can do the job for about 2 kg in a clay-graphit crucible if everything is well prepared and the insulation of the furnace is well done

this one was lined with material that can hold up to 1800°C

you will have to look around, but things can be found, not for low I am afraid to say

but they are there

best regards

Jokke

Edited May 30, 2015 by Jokke

[Tim Mitchell]

Hey Jokke, thanks for sharing the pictures of your setup and info, that furnace looks really nice. I can see how lining the furnace with ceramic wool insulation (stabilised of course to protect the lungs ) would really increase efficiency. Most wootz makers that I know use more than one gas bottle manifolded together.

 

From my understanding of the Carbon - Phase diagram, the 720°C soak would help to normalise the steel and release stresses, softening the ingot, but I am unaware that carbon is able to move in the steel at that temperature, it usually has to go above Acm (where cementite dissolves) which at 1.5%C is around 960°C. He seems to be keeping the temperature below A1 (727-723°C) to stop the forming of Graphite in the ingot which a prolonged soak at slightly higher temps can cause. Niko avoids a long low temp roast of his ingots because he finds that the level of Graphite can become a problem. At this temperature though that wouldn't be a problem.

 

Good information, thank you!

 

Cheers, Tim.

[Jokke]

on FB there is a "new" wootz theme

with some interesting fotos and texts:

https://www.facebook.com/Wootz.Bulat

 

just to get some ideas...

 

best regards

Jokke

[Tim Mitchell]

Thanks Jokke, that is an interesting site, it lists a few more makers, I will have to update our list... it is definitely growing.

 

Regards,

Tim.

[Krzysztof Rusek]

Greetings to everyone from Poland.

I'm still inexperienced in wootz forging but on 10 melts 7 are succesfull. I'm using coke as fuel and graphite crucibles (A2 size). Because of fuel i cant open crucible during melt to check state of charge and thats main reason why there are 30% failures. My cakes weight around 1 kg - 1,2 kg, charges ale mostly made of nails and charcoal. Sometimes i add 50HF spring steel to obtain chrome and vanadium in ignot but those ingots are harder to forge.

Melting steel by me consists 4 stages.

1. Initial warming the kiln. It takes around 1 hour till kiln is burning properly and is nearing work temperatures.

2. High temperature melting. I incarse temperature till 1500 - 1600 C to fully melt charge. Around 1,5 - 2 hours.

3. Low temperature roasting. I lower temperature to 1200 - 1300 C to slowly "froze" molten steel. Around 40 - 60 minutes.

4. Cooling the kiln witch crucible inside. It takes till next day morning. Kiln is massive and made of firebrick (around 120 kg weight) so it cools down slowly.

Niext day when i do another melt i can thermal cycle the cake. When im in low temperature roasting i put cake inside kiln (on top of the crucible cower) and anneal it in around 1000 - 1100 C. Temperature is lower because of the high temp. spot is centered on crucible. Thats most what i can tell about my melts.

 

I'm still inexperienced blacksmith (today i cracked another cake during forging) and im still learning (mostly from my mistakes). On my site www.crucibledamascus.com you can see few forgings of my steel (not done by me, im too inexperienced) and on facebook profile you can see my melts.

 

In Poland there are 2 more people capable of wootz smelt and forging (of which i know) Adski and Strzyż. What are their metods aim not entirely sure.

 

I want to thank all community and author of tutorial on pimalfire.

http://primalfires.yuku.com/topic/1950/Tutorial-on-making-wootz-crucible-steel#.VYquEEZik4s

That gave me nice start to smelting wootz and allowed to start my adventure with steel melting and forging.

 

Sincerly

Krysztof Rusek

Edited June 24, 2015 by Krzysztof Rusek

[Jokke]

Tim,

the main reason why people use more than one bottle is icing during high use of gas

I usually put the gasbottle into a water bassin, to keep it "warmer"

 

I have not yet tried to put two or more bottles in line..

 

I am still working on my last pieces with files,

as I find the time to go to my workspace

 

best regards

 

Jokke