|Wrought Iron 1 (2014) - Hector's Bane (2013)|
I decided to test etch the finished polished blade (short time in ferric chloride). The results were quite a surprise:
The effect is subtle. What is revealed is most likely two things, which illustrate the important differences between antique wrought iron and modern industrial steels. First, the colour shifts do mark slightly different carbon contents, here only slight differences through the metal. Second is the resistance to acid provided by microscopic inclusions of glass slag through the material. Both of these elements are themselves of the hammering, folding and welding process used during the creation of the original metal bar.
Also revealed are the distortions in shape from the forging process creating the new blade profile from the starting rectangular bar.
Hector's Bane is the first 'art knife' using my bloomery iron.
I had presented the blade when I first forged and polished it, and it was received very well. (It won 'best in show' at the Summerfolk Artisan's Gallery in 2013.)
I had felt that the polish needed to be completed with one higher grit level, and undertook this process in the early spring. As much as a test process, I decided to treat the new surface with a light etch. This was the final result:
What is interesting here (if something that should have been predicted) is the mottled variation in colour over the bloomery surface.
The central core of high carbon shows as the darkest colour at the exposed edge and in gaps along the back.
The other colours over the surface are the result of variations in carbon content in the original bloom. Interesting is the location of the pale areas (low carbon) and darker ones (higher carbon). The original bloom was flattened, then cut down the centre. The two places were positioned with the central part of the bloom pieces set towards the cutting edge. This was done deliberately to ensure a solid weld at the cutting edge, plus creation of a fragmentary line along the knife's back. You notice that the areas of lowest carbon (pale) are concentrated towards what would have been the centre of the original bloom.
Carbon was obviously being absorbed into the bloom from the encasing slag environment during the last part of the smelting process.
Both of these blades will be part of my presentation (offered for sale) at Summerfolk (Owen Sound - Aug 20 - 22)