Wrought iron surprises people in a knife. It is an old low-carbon iron, and mild steel largely replaced it as a building material in the 19th century. So why do I still use it?
What wrought iron is
Wrought iron is iron with slag inclusions. Slag is a glassy leftover from old smelting, and in wrought iron it runs through the metal as stringy fibres. The fibres give it a grain, a bit like wood.
The fibres are not a defect. After etching, the surface looks rough and catches the light in its own way. Reclaimed wrought iron also carries the history of whatever it was before, like an old chain or a farm machine.
How I use it
Wrought iron is too soft to hold an edge on its own. Its carbon content is close to zero, so it does not harden in any meaningful way. What it can do is form the body of a clad knife, with a high-carbon steel core doing the cutting.
I build these knives as san mai. San mai means three layers: a hard steel core between two layers of softer metal. Here the outer layers are wrought iron and the core is 80CrV2, a high-carbon steel with chromium and vanadium. The wrought iron protects the core and absorbs shock. The core is exposed at the edge and takes the edge.
From pin to knife
The wrought iron in these photos started as pins from an agriculture machine. I forge a pin into a bar, forge the bar flat, and etch a flat to check the pattern. Etching is a short acid bath that darkens the metal unevenly, so the fibres show as streaks. This tells me what the cladding will look like before I build a knife around it.
The knife
A wrought iron clad knife looks different from anything else I make. The etch brings out the slag fibres as streaks in the metal. The pattern is not as controlled as damascus, and looks more organic. Each piece of reclaimed iron is different, so each knife is different.
The knife also cuts well. Wrought iron is tough and slightly flexible, so it takes up shock before the harder core feels it.
Is het de moeite waard?
If you want a knife with material character and history, yes. Sourcing and preparing reclaimed iron takes extra time, and so does the forge weld between two different metals. The reward is a knife that looks and feels unlike one made from modern steel stock.
I find wrought iron one of the more interesting materials I work with. Read more in my post on smeedijzeren bekleding, or neem contact op als je er een wilt.