Make your own ferrofluid in 5 minutes

Step 5 What Other People Do With It

There's a lot of cool things people do with ferrofluid.
You can make brakes with it by putting some fluid between a wheel's axle and hub. The wheel will spin freely as the fluid acts just as a liquid lubricant, but if you apply a magnetic field, you're suddenly putting a lot of friction of the wheel's rotation.
The good folks at the Univeristat Der Kunste Berlin made a ferrofluid display that can play Nibbles: http://www.digital.udk-berlin.de/en/projects/winter0405/main/hauptprojekt/snoil.html
I'm building on-the-fly braille translators and tactile interfaces by sensing if people are moving the fluid: http://www.artiswrong.com/ffb
(just pictures and movies, no explanation/writeup yet....)

Comments

[flashsumner]

it's too bad the fluid becomes jagged when magnetized. I've been wondering if it would be possible to make a relief globe of the earth and 'cover' it with some sort of fluid that could 'stick' (perhaps magnetically) to the globe, filling the depressions like the oceans on the earth. Mercury would work but is obviously impractical for safety reasons. This ferrofluid would be an option except it doesn't really act fluid-like when magnetized.

[Protocol512]

well it's not really supposed to become solid at all,.. it's basically supposed to remain a liquid, reactive to magnetic field. When made right, the particles, and the fluid don't separate. And when they do, it's because of a constant force. A solid state magnet only pulls one direction, constantly. When you use an electromagnet, and ferrite, the change in direction occurs so quickly, that the solids never have time to settle out of the fluid. When this occurs, you can idealy suspend the solid, and liquid, in a perm. state, without separation.

[ocbarterguy]

I was just wondering, I just bought some "Ferrofluid" on ebay, got it home, and noticed that it coated my beaker in a film as it passed over it. After doing some research, I found that you can put it in a median like alcohol, or ethenol to prevent it from sticking to the glass: But when I tried with a 50/50 alcohol solution, the mixture became foggy at the top, and there are what look like random sized filings, almost like the guy sold me really cheap stuff. I've seen several videos in which the fluid literally behaves like an individual entity, not a blob of metal stuff. Basically my question is: How do I get this stuff to behave like it is supposed to in a small glass beaker without it looking cheap and foggy? Thanks so much!! -Jay

[von rad]

Ferro fluid is nasty.  In spills, accidental contact, multiple field interactions - experimentation means discovery so no predictable results = "ferro fluid is nasty".  Recently I have been using glass, aluminum and wood to identify magnetic reactivity and (visually) field definition.  In air it takes a long time to "grow" the field.  The advantage over the ferro-fluid is that you can see the "grain" of the field, you can measure angular "reactions" and determine how vectors were resolved.

VR,

[prank]

would you want the fluid to move around afterwards? If not, you could use a clear epoxy. What do they use for fake water in the museum displays of swamps and rivers?

[theblasto]

Epoxy is a fantastic idea! If you mixed the MIRC with a light-weight liquid epoxy (working quick)... applied a magnet... and let it harden... you'd have a nifty little piece of permanent art! :)

[flying texan]

what if you used grease in stead of oil, then heat it to drain excess, then the sticky grease would keep it from splitting to make it nice and smooth. another thought would be to mix the MIRC with gellotin, I wonder what that would do? how would you grind ferric oxide as fine as graphite lube.

[von rad]

A rock tumbler using spherical metal balls or ball mill break it down to a fine grain.

VR

[general-Insano]

Would it be possible to combine this instructable with the Pneumatic Muscles

[xbh1h2]

Can you use iron filings?

[cobrap2k]

u could use commercial ferrofluid here are vids

http://mrsec.wisc.edu/Edetc/cineplex/ff/text.html

[neo-rj]

is there any way to get the fluid back after it has been magnetized? would heating it work? RJ

[prank]

if you remove the magnetic field, it becomes a fluid again. The particles in the fluid aren't inherently magnetic--they just align with the field lines.