Zen_Hydra
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Born with a heart full of neutrality
Posts: 2,625
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Post by Zen_Hydra on Aug 31, 2017 16:57:02 GMT
Does anyone here have any experience (first or second hand) with using thermite to produce crucible steel?
I'm curious about how well it might work, as it seems like a relatively inexpensive means to produce one's own bespoke steel.
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Scott
Member
Posts: 1,675
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Post by Scott on Sept 14, 2017 3:50:56 GMT
It could work I guess, but how big a reaction would you need to produce a usable amount of steel? I know they use thermite to weld train tracks together. There's a funnel shaped crucible that the reaction takes place in, the molten metal then poured down to join the two pieces of track.
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Post by bfoo2 on Sept 14, 2017 21:15:50 GMT
Afoo : I know what we're doing over Christmas
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Post by Afoo on Sept 14, 2017 22:40:48 GMT
Does anyone here have any experience (first or second hand) with using thermite to produce crucible steel? I'm curious about how well it might work, as it seems like a relatively inexpensive means to produce one's own bespoke steel. so, I have done the thermite reaction many times as a science demo for teaching chemistry. I have done it on small scale, but in a wide enough range of guises and settings to have some idea how it behaves a) it does not produce steel. Thermite is a single displacement reaction in which iron oxide and aluminium react to form iron and aluminium oxide. Note that the iron does NOT contain carbon, or any other alloying metals. You CANNOT add carbon to your thermite, do not try. Carbon and other "volatile" compounds will rapidly vaporize when exposed to the searing heat of thermite, and will cause it to explode violently and unpredictably. Military-grade thermite may have carbon mixed in for this purpose, but I would argue that anything the military does to make thermite MORE dangerous should be avoided. b) thermite sucks. I have actually tried to cast things using the iron from thermite. The problem is that thermite generates iron AND aluminium oxide - in other words slag. I find that the reaction proceeds too quickly to separate out the slag effectively. Perhaps if you do it in a large enough volume its possible, but that also makes it more dangerous. As they say on mythbusters - once you light thermite, you can't put it out. It was used to weld railways together. However, its not like they used thermite to make a giant pool of metal which they leisurely cast into shape. What they did was have a giant mold which was clamped over the section they wanted to weld. They then put a pot of thermite ontop and set it off. The molten metal would drip down as it formed to weld the tracks in place. It worked well enough, but I do not think it is precise enough to give you sword-making material, both in terms of controlling the metal flow or its composition. Its also telling that we moved away from that as soon as we invented portable generators and other methods of welding things together in the field. On the flip side, in small amounts its quite safe - I set off batches indoors in my lab and classrooms all the time. The materials are very cheap (you can get iron oxide and aluminium from pottery stores - sold as glaze-making materials). The fuse I use to light the thermite is a magnesium ribbon you can get off ebay, though a road flare will do. The containment vessel I use are clay flower pots. Can always experiment and see if something works for you. You can use different powder grain sizes to control the rate of reaction etc. You can also do thermite with other metals - you need a metal oxide, and a pure metal which is higher on the reactivity scale. For example copper oxide and aluminium would give you molten copper and aluminium. The reactivity difference between copper and aluminium is greater, so the reaction would be more violent. Conversely, you can iron oxide and zinc, with zinc being the more reactive metal which "steals" oxygen from iron. This would make your reaction slower, though I am not certain if the boiling point of zinc is high enough to avoid the mixture exploding once you set it off
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Post by Faldarin on Oct 12, 2017 22:25:03 GMT
Potentially related to this discussion, a little tangentially, a video that dropped yesterday. It was entertaining to watch, at least.
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