Damascus Steel by Mr Owen Bush on 20th February 2015 Mr Bush began by showing a short film “Forging Soul into Steel”. It showed iron being converted to steel in a furnace, then the forging processes to make the shape of a knife, finishing and grinding the edge. The different stages were shown with different knives, and not all would have been sharpened to have a razor edge – as one large one was - and able to gently shave hair from his arm. Mr Bush trained as a blacksmith but is now mainly a blade smith, making Damascus steel blades. He uses the European pattern welding technique which dates from Saxon times. A strip of high carbon iron (steel) is welded to a strip of low carbon iron; the former can be sharpened to an edge but is brittle, while the latter is malleable. A skilled sword smith can use pattern welded strip to get a good edge on a robust sword. High and low carbon strips are forge welded to form a single bar, which is folded and forge welded to itself – this can be repeated as many times as desired, from two or three times up to hundreds, and the bar can be twisted between stages (eg four twists per cm in a 1 cm square bar). Damascus steel is characterised by its watery patterning, caused by differential reflection from the two (or more) metals used to make it. The patterning is random, due to the hammer blows during the forging. The pattern is usually revealed by etching the surface; Mr Bush uses any strong acid, but favours ferric nitrate. One axe he brought to show us was made with alternating layers with high nickel and high manganese content. Phosphorous is another element that can be incorporated in the iron. A large knife is made from several forged and twisted bars; the strong back of the knife from a bar with relatively few layers, the centre with bars with more layers and the edge bar with many layers. Swords, with two cutting edges, have the strong bars in the centre. The Saxon word for a knife is seax, and this is used for knives made by pattern welding. Iron is normally smelted from an iron oxide ore which is heated with charcoal (carbon) which becomes carbon monoxide then dioxide, reducing the ore to leave a low carbon (wrought) iron. Damascus Steel is so called because Damascus was the principal trading centre for swords, some made there but most from the Middle East and India, using a process dating back at least to the first century BC and continuing to the 18th century. A crucible steel, known as wootz, was used. This was iron heated to just below its melting point in a crucible with added charcoal to give its surface a high carbon content. The crucible kept contaminents out and the charcoal ensured a reducing atmosphere within. No initial welding was necessary, but subsequent forging was as described above. The various sword smiths closely guarded the secrets of their precise methods, which have now died out. However their products were (and are) highly sought after. Later the Scandinavians developed the pattern welding process: forging heated bars of iron & steel together by hammering them down to a thin sheet, then folding the sheet and hammering the two sides together, and repeating several times. This process was brought to Britain by the Saxons, and is the one Mr Bush has mastered. At first he started with iron and steel bars as his raw material, but now he is making them too by the bloomery method as used by the Saxons (with some mod cons). Two ores are available: ferrous carbonate (siderite) from Britain; and mixed iron oxides (magnetite) from Scandinavia. Mr Bush’s bloomery comprises a vertical cylinder as the furnace set on a base with a vent for air to be blown in. The air is traditionally blown with bellows, though Mr Bush uses an electric pump, and the vent is fitted with a small heat resistant window so that he cans see how hot the furnace is. A charcoal fire is lit in the chimney, and when hot enough a mixture of iron ore and charcoal is added. The fire does not use all the charcoal so the excess is available to reduce the ore to iron. The working temperature is between 1200 and 1400OC. The iron forms a bloom, covered in slag, which is extracted and hammered to remove the slag. A smelt can be done in a day, the bloom extracted in the evening, and the slag hammered off the next morning. Depending on how it is used the bloomery can produce low or high carbon iron. Having made low and high carbon iron, it takes another two days to make a seax or sword. It is not known how long it took a Saxon swordsmith to make a sword, but Mr Bush thought that, despite not having mod cons, it would not have been very different. The Saxon swordsmiths knew what they were doing, and they worked to a very high standard. Mr Bush brought an impressive array of swords and knives he had made. A large seax handled well and would have made a formidable weapon – a bludgeon on one side a sharp blade on the other… He also showed a picture of a Saxon sword from the British Museum. To the uninitiated it had a rusty blade with a ragged edge - the ragged edge was due to differential corrosion of the pattern welded blade; in the centre of the sword another corrosion pattern showed that the central bar had been folded into a repeating snake pattern – this would have made the sword weaker than one with a straight bar, but the patterning would have been magnificent. Saxon bling!