Make Your Own Ferrofluid in 5 Minutes

599,642

540

110

Published

Introduction: Make Your Own Ferrofluid in 5 Minutes

About: here: http://www.artiswrong.com But really, I'm just this guy. For up-to-the-minute, action-packed updates on my life (and occasional drawings of tapeworms getting it on), check out my blog here: http://ww...

Using magnetic ink and any oil lying around your house, make a substance that's liquid when it's sitting around, but turn solid in the presence of a magnetic field

Step 1: Intro

This instructable will show you how to make your own ferrofluid. A ferrofluid is a fluid with magnetic particles in it, and if the fluid is exposed to a magnetic field, all the magnetic particles will align with the field lines, and making the fluid much more dense. There's a lot of cool things you can do with this fluid. Enjoy!!!

Step 2: Get the Materials

This is just about the simplest ferrofluid you can make. You'll need two basic materials: magnetic (MICR) ink, and a household oil. I've tried a couple types of oils, and it seemd like a light lubricating oil works best, but any cooking oil will work fine, as well. The amount of oil you have is pretty much the amount of ferrofluid you'll get out--about 50mL is good for starters, but feel free to make as much as you want.
The ink is a dry magnetic ink that's used to print checks and other documents that use magnetic character recognition (check out the wikipedia article at http://en.wikipedia.org/wiki/Magnetic_ink_character_recognition if you want to know more about this awesome technology). You can get a box of it on ebay for about thirty bucks (search for MICR or magnetic ink), and you can also get it at http://www.expresstonercartridges.com/okidata.htm. It's going out of style, so you'll have to poke around a little bit to find it. It's important to remember that you don't want a toner cartridge--just the toner.

Step 3: Mix It!

Pour some oil into a mixing cup. Add a bit of the ink, and stir it into the oil. You're making a suspension, so the ink won't dissolve in the oil. Just stir it. Keep on adding ink and stirring until you have a thick solution. There's no exact science to this. A good guideline for identifying a well-mixed fluid is that if you tip your mixing cup, the fluid should ooze rather than slosh.

Step 4: Play With It!

Grab your favorite permanent magnet and hold it up to the mixing cup (don't touch ithe fluid with the magnet, or even get close, unless you enjoy cleaning). Watch how the fluid turns from liquid to solid as you bring the magnet closer. Show your friends the horrible oily liquid you have in a cup, and then simulatenously slap a magnet onto it as you harmlessly 'dump' the cup over their heads (practice this first). Buy some cheap solenoids from http://www.allelectronics.com and electrically change the consistency of the fluid. Just enjoy!

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....)

Share

    Recommendations

    • Microcontroller Contest

      Microcontroller Contest
    • Casting Contest

      Casting Contest
    • Make it Move Contest

      Make it Move Contest
    user

    We have a be nice policy.
    Please be positive and constructive.

    Tips

    Questions

    110 Comments

    For rare earth magnets cheap, hit up a two way radio shop. I'm constantly replacing speakers in portables (uh, walkie-talkies to those not in the industry). The, more or less, dime sized neo magnets are what I use to hold a lot of tools suspended from the four foot fluorescent light over my repair bench. Drivers, wrenches, a hammer... They're small but powerful.
    Many manufacturers glue speakers into plastic front case assemblies which, labor cost wise means saving the customer $$ by replacing the front case. So be prepared to rip a lot of speakers out. Most magnets are bonded to the spider (speaker frame) so you may have to cut and/or grind the spider away then peel, close to the magnet, with pliers to free the relatively brittle magnet. This is worst case. I've popped hundreds loose with a screwdriver over the years.
    I keep a stack on my bench just to pull steel filings from grille cloth of radios.

    Dude, there's this thing called being smart @AbeC8

    should the magnet must have north and south poles to make it work? or a complete pull magnet will do?

    1 reply

    sorry, but there's no such thing. all magnets, be them ferrous, rare earth metal, electro, are, by the definition of what magnetism is, polarized object. The only sort of mono polar objects are statically charged objects, but to pull neutral iron like that would require a charge so high that i would start worrying about inducing (or producing deepening on the charge) actually dangerous amounts of lighting. think, thunder clouds are one of the biggest and most powerful natural forms of static charge there is and you don't see coins being lifted from the ground.

    There is something wrong with your last two links.

    you may have problems using most laser toner as it is electrostatic not magnetic in its operation.

    i wish it was magnetic as then it would be much easier to clean up when spilled

    So...I made the ferrofluid, bought a 200lb rated, rare earth magnet and it just makes a big bubble without the "spikes" from the magnetic currents, like I've seen here. The fluid does seem to be very magnetic as it should be. Anybody have any ideas of what I might be doing wrong, or not doing?

    Ok some people have been getting no affect and most toner particles are magnetic, the reason for no or little affect is your magnet. The magnet your using should have a pull force of about 100+lbs. If you have a local hardware store you can probably buy a magnet there for 5-20$ and if you don't goto This Webiste and purchase a block magnet with a high pull force and make sure it says diametrically magnitized (that means it has a north and a south side). try to keep it under 200lbs unless you have TOTAL experience handling Neomodyuim magnets. BTW adding some household ammonia will help the particles stablilze so they don't clump add about 2 drops for every once of ferrofluid and make sure you don't eat the ammonia or mix it with another chemical unless its has been approved and is safe to handle.

    Cheers.

    3 replies

    can I have a direct link to a magnet that strong for around $25 OR LESS (hopefully) please? i cant find any of those!

    I have a magnet with a pull force of 250 lbs....that should do it, right? :P I am so making this! I love magnets and stuff like this.

    well you have 2 use a earth magnet

    vivid description on how to make a liquid magnet
    http://blackpegasus.hubpages.com/hub/How-to-make-Liquid-Magnet

    Any thoughts on which might be the best out of this list? And how much?

    1 reply

    (This is a reply to willvb13 - the comment system wasn't letting me reply)

    here is blog on it

    http://blackpegasus.hubpages.com/hub/How-to-make-Liquid-Magnet

    ferrofluid was invented by NASA to move fuel in null gravity.

    this is very cool but it appears your batch doesnt have quite enough oil to be smooth.