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Solar powered light cutter mimics lazer?
  • Hi all,
    I'm not real technical but when I saw this on slashdot I thought of you off-the-grid guys and how amazingly useful this device could be, and was wondering if anyone was working on an off-grid lazer cutter like this that does not require fuel.

    "Industrial designer and tinkerer Markus Kayser spent the better part of a year building and experimenting with two fantastic devices that harness the sun's power in some of the world's harshest climates. The first he calls a Sun Cutter, a low-tech light cutter that uses a large ball lens to focus the sun's rays onto a surface that's moved by a cam-guided system. ... Next, Kayser began to examine the process of 3D printing. Merging two of the deserts most abundant resources, nearly unlimited quantities of sand and sun, he created the Solar Sinter, a device that melts sand to create 3D objects out of glass."
  • 5 Comments sorted by
  • The Sun-Cutter uses a small glass ball lens. My idea is also to use a large ball lens made out of plastic and water. It could be used to boil water or drive Stirling engine.
  • I think (very un-expert, I have only essentially a layperson's 'this would be cool' idea) that there's a lot of untapped potential using sunlight, especially in any applications calling for heat ... I think we can use the sun's heat a bit more efficiently over using solar cells to derive electricity to then use that electricity to do other things.

    I was also wondering if the possibility of a "super-solar concentrator" (would, I think, need to be much bigger scale than the steam generation I browsed as one of the current GVCS) to create a 'solar concentrator foundry,' using a large concentrator system to melt steel or other metals into a liquid state, which could then be poured into molds.  I think that would potentially lower the cost of obtaining materials to build the stuff for the GVCS.

    I'm not an engineer nor an expert in power, so I wouldn't know the first thing how to design a practical model, but I think the basic idea could be practical if someone with the knowledge could design it.  The big cost of working with steel, its my understanding, is how much electrical power it takes to heat the iron to its melted state.  The sun gives plenty of energy, especially if desert sites were chosen for the solar foundry.  If OSE communities didn't have to buy steel, and could instead buy scrap iron rusting away in scrapyards or other sources and make its own steel in solar foundries with the most readily available energy on the planet (sunlight).
  • Vote Up0Vote Down
    September 2011
    The big problem with solar energy in most climates is that it is undependable.  Yeah, if you live in the sub-sahara you can rely on the sun being out most of the day, but temperate climates have clouds part or most of the day.  Then there is a problem with losing your energy source every time night rolls around.  Can you imagine getting all set up to cast a big part out of steel to be melted in a solar furnace only to have a storm put you out of business for 2-3 days?  Frustrating, to say the least.

  • Steel isn't readily consumable, so it doesn't need daily production.  A lot of foundries here in the U.S. are idle, shut down, plenty of scrap to melt but no customers to buy new steel they could make from the scrap and they can't lower prices because energy costs make it cost too much.

    Every region would be different.  I dunno if it would violate the spirit of OSE to trade stuff that's readily made in one area for stuff that another area is better suited for because of climate, but communities in desert areas, like the Mojave, could have a solar foundry and trade the steel they make ... say, Missouri, more in the 'breadbasket' in exchange for some crops that would be more practical to grow in Missouri.  I guess that kinda goes against the ultimate idea of being completely self-sufficient and producing everything you need instead of having to trade or buy it, though.  I think it would help make hot, arid climates more sustainable though.
  • Vote Up0Vote Down
    September 2011
    And now for a practical look at recycling steel...

    Generally, for any high-quality steel making process, it will typically go like this:

    The scrap steel is melted down to molten, and then fired in a reducing environment (with excess carbon & limited oxygen or air injection, to burn off the additives, including the carbon that make it steel vs. raw iron).

    The molten iron is poured off, as it is much easier to separate from the slag which will be everything else that didn't get burnt off, and the iron is poured into ingot molds for later use, or poured into other crucibles for mixing & making steel.

    On a small scale, it might not be poured into a new container, but instead, the alloy materials may be added to the original crucible, and it is then mixed to form the alloy desired, before pouring into the molds for use as steel.  The lances that are used for injection of oxygen (or plain air for the old-fashioned Bessemer process) can be cooled with a water jacket to keep them from burning up (too quickly).

    Once the iron has enough carbon in it to be proper for the mixture, adding air or oxygen will make the reaction exothermic, so one wouldn't need to keep heating it further, but a straight induction furnace simple won't have the chemical properties needed to recycle scrap steel & iron to high quality steel, without a great deal of external control of the environment, because at the temperatures involved, it is nearly impossible not to just make a lot of oxides (slag & rust) if one doesn't control it.

    Face it, there's much more to making steel than even just getting an induction furnace, and right now, coke is still one of the best raw materials to use for making iron from steel.  An induction furnace can be useful for melting many metals and do a good job of it, but process control to make specific kinds of steel from other kinds of steel or scrap of unknown alloy will be a crap-shoot with no way to make the process repeatable.  Chemically, one will still have to start with scrap and reduce it to iron, and then start over, or have little control over the mixture in the alloy.  Lots of nasty chemistry at high temps involved there, with lots of horrid smells and potential air pollutants to deal with along the way, without some major prep work for scrubbing the exhaust.

    The induction furnace looks really good in concept, but even if OSE can get there, they are still a long way from using it in the fashion they've described in the goals, as presented.

    I still wish OSE luck with it, but I don't have inflated hopes that I could use this for anything in the next 5+ years or more.

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