Well, not quite. Unfortunately, not only am I late with this post, I also don't have video to show for it. The video is sitting on the camcorder, and I can't seem to find the mini-firewire to firewire cable to pull it off.

So, pretend you're looking at an electromagnet strong enough to make ferrofluid show its spines. I used a core of low-carbon steel, about 1" in diameter, wound with about 24-gauge enameled wire. The bench supply I was using was only good up to 3 amps, which wasn't enough to make much of an effect. I hooked it up to a 12v lead-acid battery, though, and that did the trick. Based on the voltage drop and coil resistance, I estimate it was pulling about 27 amps off the battery. That heats the coil up right quick, however.

I now need to experiment with different coil geometries to see if I can get something that produces an interesting effect in the fluid without overheating quickly. I also need to look into a higher-current bench supply. The battery doesn't last long between charges.

Also I need to get a cable for the camcorder soon. I have all kinds of rad video to post: the new year's party, laser interference patterns (testing a vibration isolation table), a high-voltage water bridge, and the ferrofluid of course.