Wrought iron is the “old iron” of blacksmith’s myth and legend.
It is a traditional material made by puddling or in a finery furnace. It has silicate (slag) stringers within its matrix and etches wonderfully giving cloudy swirly patterns on the side of the blade. I have combined this material with modern steel cores giving a new twist to the oldest combination of iron and steel.
I was lucky enough to obtain my wrought iron from the Whitechapel Bell Foundry before it shut down and I am using this bell fitting and bell clapper iron as cladding in my wrought iron san mai material.
Wrought iron must be forged hot! And this san mai is no exception. If it is worked too cold the solid slag will crack so the material ideally needs to be forged at a bright orange temperature (near welding heat) . I am offering wrought iron san mai with cores of 26c3 (known as spicy white), 1095 and En42J steel. The billets have a core thickness of 1/3 of the bar (perfect for forged blades where the edge has been bevelled. If you want this material for stock removal I would recommend a core thickness of ¼.
Heat Treating instructions
I apply anti scale compound to my blades when I normalize and harden them. Normalize Damascus steel at 800C and then air cool. I would recommend 3 normalization cycles. Austenise at 800C and hold at temp for 5 minutes. Harden by quenching into a fast quenching oil pre heated to at least 40C. Temper immediately at temperature ranges between 180C and 250C. I temper kitchen knives at 190C or 200C and choppers at 220C and axes at 250C. To soften for drilling I recommend a sub critical anneal, heating the steel to 700C or dull red if you do not have a heat treatment oven and allowing to air cool. If necessary repeat a few times.
Grind all decarburised material from the blade prior to etching. (Hardening will often leave a thin layer of decarburised material on the blade this needs to be removed as it can look patchy in the etch. Grind to 400 grit then clean off all fingerprints with clean 800 grit abrasive on a rubber block. I find abrading the blade gives a better finish than acetone or washing up liquid and hot water. Etch in 1/3 strength ferric chloride until desired depth. Neutralize the blade in bicarbonate of soda solution and then clean in hot water and washing up liquid and rinse with cold water. Ferric reactivity is very dependent on temp. and I find etching can be as quick as 5 min in the height of British summer and take many hours in the winter. A darker contrast can be had by first etching in ferric and then transferring to 50X strength instant coffee. Neutralize as normal after coffee.