Why were the ingots mostly round?

[Jens Nordlunde]

Hi Jeff, thank you for your interesting answer.
Since you write that a ‘two sword’ ingot easily could end up as a few daggers ingot, there must be a big difference of how much slag there it in the different ingots?

[Jeff Pringle]

No, not slag - sometimes there are 'air' bubbles that need to be worked around, sometimes cracks appear. Typically slag inclusions in wootz are fairly minor.

[Jens Nordlunde]

I am rather puzzled. ‘Air’ bubbles, what is that, and how do you work your way around them? It is the first time I have ever heard about it.
The cracks are something interesting. I know of course that they appeared; most of the collectors know this, but why? One would think that when a blade is heated and worked on cracks would disappear, that the forging would make the blade more homogeneous, so why are the cracks still there?

[Justin]

Thanks,Jeff.

[PUFF]

Unlike solid state smelting, the wootz smelting turn whole thing to liquid mixture. With slow cooling, liq. slag and liq. metal separated into two distintive phases like water and oil. Most of impurities partitioned into slag phase and floated up to the surface. I don't know about air bubble. Any bubble in the ingot indicates that smelting temperature 's too low and such a low smelting temp could trap some slag either.

Cracks are not "as baked" flaw. They happened when forging stress goes beyond the material elasticity (either forging temp 's too low or hammering 's too hard). Dear Jens, forging would make the blade more homogeneous as slag inclusions were forged out. But flaws like crack (or bubble) could not be closed unless you reach forge welding temperature (~1400 C). Unfortunately, wootz pattern melt down at 900-1000 C and forge welding of cracks or two ingots 's unlikely (possible but very difficult to bring the pattern black ).

Any flaw appear during forging stage can be easily work around by either trimming out or shortening the piece. IMO,As a smith, the worst flaw 's quench crack

[Jens Nordlunde]

Hi Puff, thank you for the explanation, I had an idea that it may be like you described, but I was not sure. Also I knew about the heat, but it is better to hear it one more time. Also there may still be some of the forumites who have not heard about this before.
So I suppose that the temperature of 900-100C is the cherry colour Hendley writes about.
Nice to have people like Greg, Jeff and you onboard, when it comes to the construction of our collectives.

[PUFF]

Originally Posted by Jens Nordlunde

Hi Puff, thank you for the explanation, I had an idea that it may be like you described, but I was not sure. Also I knew about the heat, but it is better to hear it one more time. Also there may still be some of the forumites who have not heard about this before.
So I suppose that the temperature of 900-100C is the cherry colour Hendley writes about.
Nice to have people like Greg, Jeff and you onboard, when it comes to the construction of our collectives.

Just a minor correction, 900-1000 C going to be a yellowish cherry, a bit sour for my taste. Nice sweet & sour cherry red 's around 800 C.