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  1. sword bad why?

    please explain to us non metallurgists why the titanium core, carbon fibre laminated sword might be bad.. when it just sounds so very, very cyberpunk..

    1. Re: sword bad why?

      Yeah, sounds cool, isn’t.

      Swords need to be strong, but they also need hardness and density.

      Density isn’t needed for weight, an ideal sword would have no weight. If its heavy, then its an axe, not a sword. A sword does need a certain strength, and the less dense a material, the bigger piece you need for a given strength. So if your steel sword is one inch thick, then a titanium one will be fatter for the same strength, aluminium fatter still and carbon fibre much larger. The titanium/aluminium/carbon fibre version might still be lighter for that fixed strength, but so what? Bearing in mind that this blade should be able to push through flesh, then the fatter, the more resistance from the body of the sword (as opposed to the edge). So steel is good here.

      Hardness here means the ability to hold an edge, which is the same as the ability to resist a scratch. Glass will hold a great edge, it isn’t strong, drop it on the floor and it shatters. Titanium is a great example of a material that is strong but not hard, it simply won’t hold an edge as well as steel. If you try to bend it, it won’t shatter, but that’s not the same as being hard. Hence they have a coating of titanium carbide on the edge, which is bastard hard. Two probs though, most carbide coatings are only microns thick, so when you need to resharpen the edge, you lose the coating. And secondly, put a hard coating on a soft surface and give it a good whack, the soft stuff underneath bends and the coating flakes off.

      Quenched high-carbon steel is hard but not tough, just like glass, so its ideal for the very edge of the sword, but no other part. But, unlike a coating, you have hard steel next to soft steel, with a gradual transition between the two, so less risk of them separating. (But it still can happen.)

      So, steel, dense, tough where you need it, hard where you need that, not the best for many things, but still the best for swords.

      (And I won’t even mention what happens to carbon fibre swords if you stick them in something hot, like a dragon.)

      1. Re: sword bad why?

        ok, so how about (hypothetically at this stage), something like carbon nanotubes – which are supposed to be even stronger (I’ve read up to 100 times) than steel, for the same weight.. it’d be crazy strong (so no breaking), but soft (so no edge), right?

        also, what does the folding-two-hundred-times that traditional samurai swords are supposed to have done to them, do for the metal, in this context?

        1. Re: sword bad why?

          Well, still depends upon density, CNT being about that of water. So you’d end up with a big fat light blunt strong sword. Would be sweet for kendo though. Still burns, so still crap for sticking dragons.

          Traditional japanese steel is full of bits of crap, all old steels were. The crap has effectively no strength, so steel can crack through the bits, so big bits are bad, and bits in the wrong place are bad. The hammering and folding just thins the bits out, breaks them up small and aligns them across the direction that a sword would crack. And then they end up stopping cracks, rather than starting them.

        1. Re: sword bad why?

          I think needs quenching. I’ll need some clarified honey, fresh urine of a billy-goat, alum, borax, olive oil, and salt.

          1. Re: sword bad why?

            Well, I was planning on coating you in differing thicknesses of clay first, so that the cutting parts cool down fast and end up harder, and imparting a curve along the spine. But I see that someone’s already done that you do 😉

        1. Potentially worse, no-one really knows. But not as bad as asbestos, probably.

          One fun thing, they conduct electricity. So if you’ve got lots of caron fibre dust floating about, computers arc out and die. So the US allegedly used a cruise missle full of carbon fibre to take out an Iraqi electricity substation without blowing it up. Sadly, however, millions of dollars of US high-tech equipment was no match for the decidedly low-tech Iraqis, who rounded up several thousand men, took the substation to pieces, cleaned the carbon off each piece, put it back together and it was working the next night. So then the US blew into little bits, like they should have done in the first place.

          1. carbon doesn’t so much as sit on the skin and itch, well it does if your grinding it, and it itches like an itchy thing, and when you get them, splinters tend to fester something nasty, and some can even -burrow- into your skin, we had a guy at work in southern spars got a tiny splinter, thought nothing of it, after a week and a hospital visit, it looked like someone had drilled his arm out with a 10mm drill bit. also for a real shock, stripping the peel ply off a 44m mast product (typicly 80 – 140 layers of carbon 20 – 60mm thick or thicker in reinforcements), after its fresh out of the auto clave and then earth yourself out while touching the carbon… your hair stands up and your arm recoils… zap…

          2. arrrgh, no edit function… the epoxy resin in the product, which you use to bind it all together is alot worse than the carbon, and apparently if a mast gets hit by lightening… it explodes….

            where did i leave my carbon rod, i hear a thunder storm coming…

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