We’re replacing “holy moley” in our vocabulary. Levitating globs of molten aluminum are that much more amazing. It’s not that we couldn’t believe it would work — we understand the physics after the fact. It’s just that we never would have thought to build an induction forge that can simultaneously melt and levitate a chunk of aluminum. (Video embedded below.)
[imsmoother] has had plans for 3 kW and 10 kW induction heaters online since at least 2011, and we’re wondering how we haven’t covered it before. Anyway, in the video, he’s using the smaller of the two to melt a chunk of aluminum.
The trick with aluminum is that although it’s non-magnetic, it’s fairly easy to induce eddy currents in it. Basically, the pulsing current in the coils creates a changing magnetic field that induces current loops in the aluminum, which act like electromagnets, creating their own opposing magnetic field. When these two are strong enough, they can suspend a block (and later, blob) of aluminum in the air.
We have no idea if this has any practical applications — it’s easy enough to melt aluminum in a crucible and this floating induction process is limited by the weight of the aluminum that needs to be suspended. But still, it’s an awesome demo. (See also this classic video while on the subject of aluminum, magnets, and eddy currents.)
Forging seems to be in the Zeitgeist at the moment. We just ran an article on direct-metal 3D printing, and you don’t have to go back too far to find projects like the Reactor Forge, a 1000 W induction solder pot, or this Kentucky-Fried furnace. But if induction is not your cup of tea, you can always melt aluminum in your microwave.
Thanks [Julia Longtin] for the unintentional tip, via HacDC‘s mailing list!