5 ms·

There's a lot of videos on YouTube of people using Fresnel lenses from old projection TV's and melting various things. https://www.youtube.com/watch?v=jrje73Ey

• ChuckMcM 11y ago
  That was where I got mine, I asked at a TV repair shop if they had one, and they gave me two! Setting the asphalt on fire was entertaining. We built a simple frame for it out of frame components at the craft store to make it easier to point. My goal was to build an aluminum can smelter. At the time I had this idea that I could crush a diet Dr. Pepper can with my hands (this I often do) and then slide it down into a crucible at the focal point of the lens, and have it melt and drip into a bucket of water below, creating aluminum bb's which would be much denser than even crushed cans. The problem however was that aluminum oxidizes before it melts, so in the ideal set up you really want it running in an oxygen free environment. Way more work than I wanted to invest. Later I discovered induction heating (which you can do with a windmill, some magnets and a coil of wire around a piece of steel (or aluminum).
  • nsajko 11y ago
    About the oxidation, have you tried using a reducing agent (Na is probably easiest to get). Did you watch those videos of guys melting aluminum in their backyards? :)
    • ChuckMcM 11y ago
      I did not try sodium. But to be clear, the picture of a place to throw my empty soda cans which turned them into melted bits was the attraction, all without hooking up to grid power. I'm not actually trying to smelt aluminum as some are. But watching folks melting alumninum is instructive.
• tomtoise 11y ago
  Oh lord, that kid getting so close to the beam to try some egg. I'm not even a father and I flinched.