Nitinol, a weird material

The first time I ever saw Nitinol, a retired Areospace Researcher I know was machining bullets out of the stuff!

A helpful page

┬áThere’s lots of vendors that supply hobbists with the material..



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7 Responses to Nitinol, a weird material

  1. Bill knighton says:

    The first and second engines were interesting. The first especially. Its rotational acceleration was furious and it looked like a high moment of inertia on that ring. It looked to be 10s of watts and neither of the water temperatures were as hot as boiling or cold as freezing, so that was doing a lot with low quality energy. I think it’s useless for solar since our solid state panels keep getting denser and cheaper. But if something could be constructed that is the size of a pressure cooker that sat on a wood stove to make a hundred watts at night that would be what off gridders need.
    I don’t see what is keeping the hot and cold water apart in his basin.

  2. Bill Knighton says:

    Rewatched. Now I get it. Totally separate tanks and the loops hinge up to pass the wall between them. I hope they keep these ideas coming. If I could have even a few percent of the energy from my wood stove as electricity for charging at night I’d be set.

  3. Bill Knighton says:

    I am still not sure I get the first machine. Are the spokes telescopic with a sleeve over each so that the force of the loop attempting to straiten presses against those white ferrules and so lengthens each spoke as it passes over the hot side?

  4. Bill Knighton says:

    Good Carnot cycle link. I like that it takes k, c or f. Maybe, if used, it would dampen the enthusiasm of politicians who think every weak idea can power a steel mill but I am encouraged. Typing in 100f as a cold reservoir and only 200f as hot we get %15. That’s pretty exciting.

  5. bob g says:

    the first time i became aware of nitanol was back in the late 80’s
    it was in an article about its use in medical surgical tools like scalpels.

    from what i read, in surgery a surgeon often will bend a scalpel for use in tight hard to get places, once bent they were thrown away and not reused, with nitanol they could be ran through the autoclave with all the other stainless tools to sterilize and come out in their original shape.

    building a heat engine is just too cool, i wonder how expensive this stuff is?

    bob g

  6. George B. says:

    My retired friend has a good list of patents to his name, he’s likely one of those guys that saw one of the first MPPTs, as he worked on a lot of space junk. We played with a few of his nitinol toys, all fun, but of course his most fun toys were not something you talk about in public, and you take them back apart after a show and tell session just in case they might break some law. And who would have the time to consult Government to know?… that may be a larger job than machinging all the parts..

    At the heart of one demo which was used for patent application, there was an expensive to build, powerful, and compact WWII drive motor, it’s a reminder of how little progress we’ve made in some areas. Don’t ever forget that a lot of WWII stuff is still pretty much cutting edge, some war efforts were done with no budget, and master pieces of engineering.

    As for the machining of bullets, B said this stuff goes through other material like butter., but if it were better than the best material, we’d have heard more about it right? And wouldn’t there be a box of Willem 100,000 FPS penetrators on the market now?

    My interest in this material is to make a cheap heat engine at least as efficient as that 1880s engine that Jay Leno owns and shows off on Youtube (thanks Jay). Maybe 1/4 to 1/2 horse power. In water pumping duty, we have cool water to allow us a more reasonable heat differential, and I guess that this is why water pumping duties seem so natural for the application. As pointed out, there may be solid state choices better today, and that may include the Peltier Junction as well. If we cover a fire box with junctions, and cover the other end of the junction with a cold water manifold, will we do as good as these old mechanical designs with less to maintain? Of course we use the electrical energy produced to drive a small and efficient motor that is placed near the bottom of the well, or to drive the sucker rod above ground. The pumped water runs through the cooling manifold on it’s way to a point of use or storage.

    Maybe we note what the Telcos have done for remote repeater huts? One charging source is pile of thermo couples driven by a propane burner. Have they done the research for us, and passed on the mechanical heat engine in favor of a power plant with no moving parts…. far higher reliability? We need look at what the people with research money have done for themselves I think.

    • Quinnf says:

      Like Bob, I saw this first in the ’80s. I think it was arterial/venous stents, coiled reinforcements for collapsing arteries and veins, that was the new application. The stent was coiled very tightly, put in place, then when irrigated with warm saline, it slowly opened and held itself in place. Don’t know whether it ever made it to market, biocompatibility is always a concern with implantable devices.

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