Why were the ingots mostly round?

[Jens Nordlunde]

Jeff, it is interesting what you write about the ingots. I have never, although it may sound strange, had an ingot in my hand. When I started to collect many years ago, there were not many for sale – but that has improved a lot in the last years, like discussed on another thread. I should have remembered the sound test, which can be used on metal, glass, porcelain and probably on many other things.

You write, “Occasional small bubbles are easy to work around, so even if they can't be seen they are not a problem.” Does this, ‘work around’ mean, that you cut the bubbles out when you have flattened the ingot? Or how do you ‘work around the problem’?

[Jeff Pringle]

The first way to work around bubbles is like an insurance policy - Usually the ingots have some porosity on one side, and you keep track of this side as you go from round to square, then make that side the back of the blade. This way they are far from the cutting edge and supported by more metal around them. I've seen old swords at auction with small seams on or near the back that are certainly the residue of ingot bubbles.
The other thing to do is to watch for the subsurface porosity to show up during the round-to-square forging and file/grind them out as needed. Any dips in the surface at this point in the process will be long gone by the time you get to the shape of a blade blank.

[Rick]

While we're discussing wootz ; I would like to dredge up a subject from the forum's past .
Once there was shown a sword with one side showing an active wootz pattern ; oddly enough though on the obverse the steel showed no pattern at all .
Any ideas on how this could have happened Jeff , or any other of our smiths ?

[B.I]

hi rick,
i have a historical opinion on this, as apposed to a metallurgical one.
for some reason, the wootz ingots were small, maybe too small to make a large blade. and so, a blade was made from different ingots joined together. this is why some indian blades have a 'scarf/lap' weld along the blades. also, why there is normally a join along the spine of all wootz blades, where ingots have been sandwiched together.
i am away from my notes, but i believe travernier mentioned this, when travelling with the moghuls in the 17thC. he said that each ingot was always cut in half, to determine the quality of the pattern. a good size sword was made from 3-4 of these halves.
occasionally, you will find a scarf weld, with one side being wootz and he other steel. even rarer, you will find one complete side being wootz, whilst the other is steel or even pattern welding. rarest of all, is both sides wootz, but sandwiched between a layer of steel (presuming it is steel as the colour seemed different). the last is a thick blade, of substantial quality.
the joining/sandwiching/scarfwelding is my theory, not traverniers. he just mentioned about the halves. during my collecting/studying i've heard many different theories about scarf welding, some pretty ridiculous (from stregthening to religious). this is one that i feel happy with, and think that travernier adds some fuel to it.

[Jens Nordlunde]

I see what you mean Jeff. How deep is a crack? If it is not too deep, you could make the blade a bit broader and grind the crack away – or is this solution too easy?

Interesting subject you bring forward Brian. I know tulwars exists having two different wootz patterns, one on each side, or wootz one side and steel without pattern on the other, but if it was possible to sandwich two half’s of a blade together, why does the cracks give so big problems? The wootz should be worked, like Puff writes, at cherry colour at about 800 C, and I understand it is rather difficult to work the wootz at such a low temperature. A higher temperature would make it easier, and also possible to remove the crack, but then the wootz pattern would have gone. I have a feeling that I am missing something – but what?

The attached picture is from a tulwar, I know it is not wootz, but have a look at the picture to the right – what is this, is it a crack or is it a scarf weld?

[Jeff Pringle]

what is this, is it a crack or is it a scarf weld?

That looks like a weld flaw - when doing layered damascus, it's easy to get small areas (or large areas ) that don't join up, that's what they look like in the finished product. If it was a crack, the 'texture' would be different, if a scarf weld, it would be going across the layers at an angle.

A higher temperature would make it easier, and also possible to remove the crack, but then the wootz pattern would have gone. I have a feeling that I am missing something – but what?

The missing bit of info might be that attempting to work wootz at welding temp results in more cracks, turning the ingot into something that reminds smiths of cottage cheese. It's not that the pattern goes away, the whole buiscut crumbles.
Which is interesting, because there are obvious examples of two ingots welded & turned into a sword and scarf welds joining two halves of a wootz blade as B.I. points out - this has mystified western smiths for hundreds of years. Obviously, they had a different way of welding than modern smiths are used to.
So the ways of getting non-patterned areas on wootz are -
- weld wootz to non-patterned steel, this should show a seam down the back/near the edge
- some methods of working wootz give it a decarburized outer layer which needs to be sanded off before the metal will show it's pattern - this usually shows up in patches, though - you'd have to be a very forgetful smith to leave an entire side of a blade in this condition
- obviously, sanding can remove the pattern, but re-etching should bring it back - that'd be the first thing I'd look at if a blade had one sided wootz and no visible seam on the back.
Here is a small test I did - wootz sides welded to 1070 commercial steel - the lower line is the weld zone, the upper line is the transition between hardended and unhardened metal - note the wootz pattern dissappeared in the hardened area. this method of pattern removal would be impossible to do on the side-to-side of a blade, but could happen on a top-to-bottom direction.

[Jens Nordlunde]

Thank you Jeff, you are very good at explaning things.
In the book ‘Persian Steel, The Tanavoli Collection’ by James Allan and Brian Gilmour I have found some interesting things. On page 114 James Allan quotes Tavernier, “This steel is sold in pieces as large as our one-sou loaves and in order to know that it is good and that there is no fraud involved, they cut it in two, each fragment being enough for one sabre”.

Appendix four is an extract from the account by Second Captain Massaliski published in Annuaire du Journal des Mines de Russie, 1841, pp 297-308 (in this book page 539). “Armourers frequently use the remains of old damascened sabres to make new ones which they sell at great profit. Through being repeatedly sharpened the blade eventually become worn, become too narrow and thus lose three quarters of their value. It is these old sabres which skilled armourers make use of. To do this they heat them and draw them out into a thin blade having the width of a good sabre and the length of two. They then prepare a blade of ordinary iron, cover it precisely with the blade of Damascus, and weld the whole together. A good armourer performs this operation very skilfully. However close examination will almost always reveal where the steel blades have been welded to the iron blade.”