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Vern Wimmer

Definitions and history of "Wootz" and such

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And I suppose quenching facing magnetic north or the ley-lines don’t come into the IDR direction? Seriously though, thank you for the explanations. If I understand correctly, you have to forge wootz slowly and lightly. Does quenching and tempering have any special requirements?

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I second Charles. Thank you to everyone contributing. Who needs present when you’re gaining knowledge. 

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Read everything you can guys, but i really implore you to just go out and do it, and then come back and reread, and do it some more. The more people getting involved the more we all gain from shared or even differing experiences.

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I'd love to jump in since I have plenty of wood, there used to be a brick operation nearby in the mid 1800s and the clay runs through a part of my property. Now if I had all of the magnetite sands I tossed out when I was messing around at gold prospecting. The big bump is our climate. It is simply too ₩£}{■♤ wet and raining for 9 months and then, we have a tiny window before fire season shuts down any burning of anything. Fire season doesn't end until the "Wet Coast Monsoon season" starts.

I have to cheerlead from the sidelines.

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Vern, forget the charcoal, use a gas furnace and forge, and use clay graphite crucibles.  You won't have the problem with the rain then and you can still play with crucible steel.. :)

As far as quenching, you need to quench from critical temperature (A1, non-magnetic) into heated, thin oil for general use. This will give an edge of marcasite and a body of perlite. You can also do a hot air blast quench which will give a fine pearlite structure but not as hard an edge. I have also heard of using a slicing partial quench through water and then allowing it to cool the rest of the way in air for use with wootz razors.  This ends up with a bainite like structure apparently. 

The reason for heating the oil is that if it is not heated, the oil doesn't move away from the hot blade fast enough to give you a proper quench and the edge will not harden properly.

Don't use water or the steel will crack, it doesn't like the sudden shock.

Tempering is the same as any other carbon steel and multiple tempers seem to be a good thing. 

You have to be careful when doing your heat before quenching, that you keep your furnace at least a neutral atmosphere or it will pull too many carbides out of the surface of the blade and you will have to sand off too much of the blade surface to reach the surface pattern again.

 

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From what I have seen of the crucibles which have been made in old times, they used a ball clay which was low in impurities (fluxing elements such as iron oxide or potassium etc.) They often added a grog to the clay to help keep the crucibles from shrinking.  This grog was quartz or old crucibles which were crushed to coarse grit. 

Water is a big issue with the crucibles, and you have to dry them out really well or fire them very slowly to stop them from exploding.  Those who used water in their crucible construction in the desert regions air dried them and then would have done a slow firing. 

Those who were in the tropics such as the Indian processes, used rice husks in their clay and mixed up the crucibles with oil so that they didn't explode when heated.  The process in some parts of India was a round the clock process and they would have needed a way of having an air/sun dried crucible which could be placed in a furnace that wasn't cold and still have no cracking.

Some modern smiths use a red fire clay mixture and it seems to work well for them, just remember that the lower the carbon content you have in the ingot, the higher the temperature and the more likely the crucible is to fail.

It would be good for other smiths to share how they make crucibles.  I have made crucibles out of cast refractory cement and they work well except they don't like any fluxing ingredients in your melt :(

Edited by Tim Mitchell

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31 minutes ago, Tim Mitchell said:

Vern, forget the charcoal, use a gas furnace and forge, and use clay graphite crucibles.  You won't have the problem with the rain then and you can still play with crucible steel.. :)

As far as quenching, you need to quench from critical temperature (A1, non-magnetic) into heated, thin oil for general use. This will give an edge of marcasite and a body of perlite. You can also do a hot air blast quench which will give a fine pearlite structure but not as hard an edge. I have also heard of using a slicing partial quench through water and then allowing it to cool the rest of the way in air for use with wootz razors.  This ends up with a bainite like structure apparently. 

The reason for heating the oil is that if it is not heated, the oil doesn't move away from the hot blade fast enough to give you a proper quench and the edge will not harden properly.

Don't use water or the steel will crack, it doesn't like the sudden shock.

Tempering is the same as any other carbon steel and multiple tempers seem to be a good thing. 

You have to be careful when doing your heat before quenching, that you keep your furnace at least a neutral atmosphere or it will pull too many carbides out of the surface of the blade and you will have to sand off too much of the blade surface to reach the surface pattern again.

 

Looking at it that way I become curious about the possibility of doing very small "runs" with my forge. Something around, if the smelting gods smile on me, a one-blade size just to "play" with. Given the loss, slag, etc is it possible in amounts that small? What about stack height etc..?

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The problem with doing very small volume runs is that the smaller ingots don't get the same sheet like structure that the 1 - 2 kg ingots get.  Thickness reduction is key to lining up the sheets of carbides, the greater the reduction in thickness, the better the sheets line up.  You can get a bit of a dendritic pattern in a small ingot, but to get the watered patterning it is not the same. 

 

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And doing 1-2kg pucks is next to impossible without a power hammer and to a lesser extent a press .

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I’ve never heard of using oil instead of water in the clay. That sounds like a fun method to try. Should canola be an acceptable oil in this application?

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3 hours ago, Tim Mitchell said:

The problem with doing very small volume runs is that the smaller ingots don't get the same sheet like structure that the 1 - 2 kg ingots get.  Thickness reduction is key to lining up the sheets of carbides, the greater the reduction in thickness, the better the sheets line up.  You can get a bit of a dendritic pattern in a small ingot, but to get the watered patterning it is not the same. 

 

 

2 hours ago, Daniel Cauble said:

And doing 1-2kg pucks is next to impossible without a power hammer and to a lesser extent a press .

I have both the hammer and the press, What size crucible does one use for this size puck?

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8 hours ago, Daniel Cauble said:

And doing 1-2kg pucks is next to impossible without a power hammer and to a lesser extent a press .

Not quite Daniel, I have always used a 16lb hammer one handed to forge 2kg ingots, it does take awhile and probably longer than some have patience for, but it works fine.  If you get impatient, rope a friend in as a striker, it makes a real big difference!

As far as crucibles, for a 2 kg ingot you will need around a #6 bilge sided crucible.  You can make a crucible which is taller and slightly narrower if you so desire, which will make a more egg shaped ingot.

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I was asked about historical recipes for wootz and if we could add some to the thread.  This first one that I am adding is the process from the Mysore region of India. It is important, in that it is one of the processes which is associated by many to be how they made the blades which we term Damascus blades or Wootz blades....

Some of these ingots were not used for producing blades, there were also variations of the process as will be seen from the excerpt that I include below.  I was going to post it in the form of a summary, however I think it is better if the whole account is read to show how the processes in this one area were similar but also different.  I have a copy of Buchannan's personal published account, but it differs so much from this account here that I really don't know what to make of it. Perhaps this was from a personal diary or a separate published account I don't have a copy of.  Anyway the accounts here are more precise. This article excerpt was written in 1864 with the accounts going back to 1800.   Southern Indian Wootz Accounts C1807.pdf

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I mean, i can work 10# bloomery by hand. I wont recommend it though. I think my wording is off calling it next to impossible. Just....not fun at all lol. Who eould do that to themselves???

Edited by Daniel Cauble

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That’s an interesting read Tim. As far as crucibles are concerned, it seems it doesn’t matter a whole lot what they are made of. They just need to stay together for at least 1 run.  Overshooting the carbon content and then decarbing the steel seems like the easiest solution if the clay can’t handle higher heats. I think I’ve had it backwards in thinking there was a secret ingredient to make the perfect clay. 

Daniel I have been that person...not by desire.  Just stubborn curiousity.  

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19 hours ago, Tim Mitchell said:

It would be good for other smiths to share how they make crucibles. 

This would be a very interesting thread to read!  

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They have shared their crucible making methods..Zeb Deming is the only person I know of that made an effort to make some. The accounts of western crucible steel making are full of crucible making info. It will be a grind for anyone, but that is the fun of it . Hessian crucibles are widely written about and would work.  I remember posting my original crucible making info on SFI many many years ago..lots of failures.

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The refractory clay which was used for the process in Hyderabad was a granitic clay which was high in quartz and in feldspar, it was exported as a highly refractory clay specifically for crucible use.  If you make your own crucibles make sure you go either very high silica content (add lots of silica and quartz grog) or make it very high in alumina content.  Try to cut it with pure silica or alumina to reduce the content of fluxing ingredients in the clay.  You can also add wheat chaff from the feed store if you want to, it will help to make a more refractory crucible.  Prefiring the crucibles is also a must if you aren't using a charcoal fire and slowly raising the temperature.  The process at Hyderabad took 24 hours so the crucibles were being prefired during the melt ramp up.  Using an unfired crucible in a gas furnace is not an option.  It will explode... been there done that and had lots of flaky chips of ceramic dancing around in the furnace.  It is a real bear to clean out too. :(

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Here are some observations that I have compiled from different accounts over the last 350 years concerning the ingots which were sold to Persia for the making of Damascus Swords.

 

Observations of the steel cakes from Golconda, (Hyderabad, Deccani, Konasandrum):

The Golconda process was a carburising process where cast iron was added to iron with a lower carbon content.

1675 Tavernier:
- The steel from Golconda is the only steel which will take a Damascene pattern.  
- The steel buns were in the past mostly sent to Damascus when trading went from India to Cairo through the Red Sea.
- The steel cakes were sold to Persia and the Punjab for the making of blades from Hyderabad (editors note)
- The Persians know how to Damascene with a sulfate etch. They can’t do it with their own steel.
- The cakes of steel are large, the size of a Penny Loaf () and are cut in two.
- Each half makes a sword.
- These buns of steel are made in Hyderabad in the kingdom of Golconda (Deccan) and reported to be the best from the villages of Nirmal and Indore (editors note)

Scott 1795:
- “The specimens of Wootz were in the shape of a round cake of about 5 inches in diameter, and one thick; each of which weighed more than 2lb.  The cake had been cut almost quite through, so as to nearly divide it into 2 equal parts. It was externally of a dull black colour; the surface smooth; the cut part was also smooth, and excepting a few pinny places and small holes, the texture appeared to be uniform.”

Muchet 1805:
- one of the cakes had two cuts in it cutting it almost in two so it was easy to break and see the quality of the steel in the middle broken section. He interpreted them as the result of crystalization, but also declared they could be cuts. These were the ingots which Holland declared were the ones made in Salem by the bloom process as they had occlusions of rust in some of the underside portions.

Abbott 1856:
- mentioned by Abbott in the Punjab Goorjrat, a 2 lb ingot which was lenticular in shape, was forged out into a bar in about 2 hours by the smith at a white heat (red heat according to edited version) This was available to be bought in Deli.  (The old white heat seems to have been our bright yellow or yellow and the old red heat was our dark to mid orange.  In the old days they went straight from red heat to white heat when describing temperature)
- This ingot was not partly cut in half but was complete.  
- Dimensions were loaf like and about 5 inches in diameter and about 1 inch thick.  
- Were available in both large and small ingots.

TL Lowe:
- examination of the remains of crucibles from Hyderabad region Konasandrum, shows crucibles from 1 inch to 5 inches interior diameter.  The 5 inch diameter ingots are the ones which the above reports are mentioning.  

 

NOTES:

- It seems that there was a mixing of ingots, some from Salem and some from Hyderabad, arriving in Bombay and this accounts for the ingots which were clearly made from separate processes which both Joseph Banks obtained and which Smith sent to the royal society. Some ingots had oxide remains in pits on the underside as described by Muchet, and these were actually from Salem further to the south according to Holland's account in the 1890s.

- It seems that the almost cutting in half of the ingots was stopped somewhere between the late 1700s and the mid 1800s. Although it was clearly a long standing practice.

- Tavernier said that the Persian steel, although very good, did not produce the Damascene process. We know that in earlier times the steel from Persia did in fact produce patterns.  However it is possible that in the later years the steel from India was found to be superior and replaced the steel from Persia.  We know that Persia used large quantities of the steel from Hyderabad. 

Edited by Tim Mitchell

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KONASANDRUM PROCESS AKA DECCANI PROCESS:

(1820-1823) from repeated visits and inspection of the process by Voysey. "Native manufacture of Steel in Southern India" - Journal of the asiatic society no.6 june 1832 p 245 [Extracted from the Journals of the late Dr. Voysey]

 

"The granitic clay of the furnace is highly infusible; it is found in the neighbourhood, and is formed of the decomposition of granite rock with small pieces of quartz and felspar, and is so valued for its refractory qualities, that it is exported for the manufacture of crucibles, &c.

In making the crucibles, the granitic clay above described is ground to a fine powder along with the fragments of old furnaces and crucibles, and the whole kneaded together with the chaff of rice and oil. The vessels are defended by a luting of the same, they are covered with a similar top, but a perforation is made in the latter. No char- coal is put into the crucible, but small pieces of kanch, or the glass formed in the process, are put at the bottom of them along with the ore, and serve of course as a flux. The crucibles are arranged and steadied in the furnace occasionally by the superintendent, with a long and stout rod of iron.

The materials used in the preparation of the steel are two different kinds of iron; one from Mirtpalli the other from Kondapur, in the proportion of three parts of the former to two of the latter. The Mirtpalli iron is derived originally from the iron sand already noticed, and is sent in the state of large amorphous masses of a redish grey color, and of an extremely porous texture. The internal fracture is often iridescent. The Kondapur iron is procured from an ore found amongst the iron clay, at a place about 20 miles distant.

It is said to be of a dirty brown colour, and very frangible. The Iron however, is moderately compact and of a brilliant white fracture. Occasionally it contains some ingredient which spoils the steel, render- ing it excessively brittle : the natives assert that the adulteration is copper, but it is more probably arsenic. The mixture being put into the crucible, the fire is excited and kept up for 24 hours.
It is then allowed to subside, arid the crucible is taken out and placed on the ground to cool. When quite cold it is opened,and a cake of steel of great hardness is found, weighing- on an average about a pound and a half. The cake is covered with clay, and annealed in the furnace for 12 or 16 hours. It is then taken out and cooled, and again annealed, and this may be repeated a third or fourth time until the metal is rendered sufficiently soft to be worked.

The steel is known by the name of Wootz in Telinga, and a Kurs, a cake of about 110 rupees weight, is sold on the spot for 8 annas. The daily produce of a furnace is about 50 seers, or in value 37 rupees. The cost of this steel is much enhanced by the exaction of the Jaghirdar who not infrequently appropriates the advance to himself, and leaves the purchaser still to incur the whole expense.

The export, however, of the metal to Persia must be profitable, as it is sufficient to bring dealers from that country and to defray the cost and risk of traveling. We found at the village, in 1820, Haji Hosyn, from Ispahan, engaged in the speculation ; and it must have answered his purpose, as he was here again in 1823, having returned in the interval to Persia and disposed of the venture. He informed us that the place and the process are both familiar to the Persians, and that they have attempted to imitate the latter without success. Besides residing at the village, whilst making his purchases, he bore a personal part in the operation, weighing the proportions of the iron, and toughness of the steel himself."

 

 

 

 

Edited by Tim Mitchell
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Thanks Timothy, You have done a lot of work..it is a fascinating topic...lots of filling in the blanks.

 

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