Craft & Design Fun & Games
How To Make Ferrofluid At Home

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Ferrofluid is one of the neatest things to see in action. Suspending liquid through the use of magnets? Super neat! Ferrofluid is a colloidal suspension of ferrous, which contains iron, and a liquid. (Some kind of oil since we all know what happens when you mix water and iron).

There are generally two ways you can make ferrofluid. The more expensive way (around $100 per cartridge of magnetic primer toner and some vegetable oil), and the cheaper way which is a little more difficult to make, but will only cost you about $10. You’ll need about 10 cassette tapes, some acetone, a strong chemical resistant bucket (this is very important), plastic wrap, vegetable oil, and magnets. Earth magnets are the better choice because neodymium magnets aren’t as good at stripping ferric oxide off of the tapes. To make, you’ll want to step outside as inhaling acetone is not favorable. You’ll break apart your cassettes and throw the tapes in your chemical resistant bucket. You’ll mix your acetone in, cover it with plastic wrap, and let it sit for an hour. When you come back you’ll have a fine black powder in the bottom of the bucket, and your tapes will look clear now. Wrap your magnet in plastic wrap and push your tapes to the side. Collect the ferric oxide with the magnet and place the powder in a small container off to the side to dry. Once it’s dry, add your vegetable oil (approx. 1.5 tsps of vegetable oil to 1 tsp of ferric oxide) and then you have your ferrofluid!

23 thoughts on “How To Make Ferrofluid At Home

  1. don’t have any old cassettes laying around…but have an embarrassing number of VHS…hmmm
    what should I look for to determine if it is a “chemical resistant” bucket?

    1. Large glass or pyrex bowl. Not plastic. I also wouldn’t use metal as this will hinder picking up the oxide.
      Vhs tape should work just as well.

  2. (Rare) “Earth” magnets aren’t really necessary, at least per the instructions. The oxide is already off the tape, and sitting on the bottom of the bucket of acetone.
    I have a bunck of both cassette and VHS around. A few boxes of floppies, too!

  3. ” (around $100 per cartridge of magnetic primer toner and some vegetable oil), ”

    If I understand the reference correctly, you can use magnetic printer toner.. which is laser printer toner or laser copier toner. (not inket copier ink)

    http://en.wikipedia.org/wiki/Toner

    If that is the case then rather than buying a full retail laser printer toner cartridge there are two other less costly and easier ways to get your hands on the powder.

    1) Laser printer/copier refill kits use bottles of toner for refilling existing cartridges. You don’t even need to buy the kits. You can just buy the bottles of toner through vendors on Amazon or copier refill supply vendors. You can buy a 5 ounce (140 gram) bottle for as little as $6.00 shipped. You can also buy the powder in C,M,Y, and K (black) colors

    2) Laser printers and laser copiers are equipped with systems which collect the “waste” toner, the powder that is sent through but is unused in making a print. Although the toner is no longer “virgin” it is still perfectly usable and more than sufficient to be recycled into this project.

    Specific laser copier and laser printers us different systems to collect the unused powder. Some collect the powder in a “waste” bottle which is emptied or replaced by the technician when the machine is serviced. Other systems send the unused powder into a waste reservoir of the cartridge it came out of originally. Your mileage may vary/ You’ll have to figure out where the waste toner is collected on your machine.

    Care should be taken when handling the powder. You should take steps to avoid breathing it and avoid getting it on any clothing or surfaces which could be stained.

    On the plus side of method #2,

    2a) the powder doesn’t cost anything
    2b) You are recycling good material
    2c) You don’t need to use any special buckets or
    deal with toxic chemicals to harvest iron oxide from VHS or audio tapes.
    2d) It would be far less effort than the tape harvesting.

    1. Regular laser printer toner won’t work. You would need the special toner used for printing the magnetic MICR codes (like are used on the bottoms of bank checks). These toner cartridges are pricy, hence the $100 cost mentioned in the article.

      1. Thanks for clearing that up Hank Cowdog,

        Forget everything I wrote about copier toner.

        Regular copier toner contains iron oxide.
        Could that be extracted and made magnetic?

        MICR toner is available in bottles for from Amazon $19.00 shipped.

        1. I’ve used my old cartridges from hp laser jet printer to make ferrofluid many times. It worked. I’m an amateur and every batch was different but still fun. I wanted different colors but only had black printer. Didn’t think of the color printers! I’ll try them. I’m looking for a way to make clear ferrofluid, any thoughts?

  4. Where I live acetone and chemical resistant buckets are not easy to come by. What do I do? (are there substitutes?)

    1. any home improvement store are paint retailer (like house paint, not art supplies) will carry acetone if they are even just adequate stores. also as for the chemical resistant bowl, there are specific plastics designed to withstand acetone which are relatively cheap, but you’d need to look up the classification system for plastics which is annoying so cooking glass ware (as in it can be used in an oven without shattering) will work. theoretically any glass ware will work, but better safe than sorry.

  5. This did not work for me. The video tapes I used I bought from the thrift store and were from the 80’s and early 90’s and the ferromagnetic particles were embedded in the plastic tape that was resistant to acetone. richard simmons survived another day.

  6. Couldn’t you just use finely powdered iron or steel and mix it with mineral oil? This method of using tapes seems like a lot of work and as you mentioned acetone isn’t the safest liquid to be messing with.

  7. Also wondering if the yellow and red iron oxide powders I found when I did a search could create some more colorful ferrofluids than the basic black I’ve seen to date.

  8. I think it matters what kind of tapes you use. Probably you don’t want to use Chromium Oxide tapes (Chrome tapes), and I don’t know what metal tapes are made of. Probably this is best for common, cheaper tapes.

    Don’t sacrifice your cassette collection for this. They might not even be the right kind of tapes.

  9. is it necessary to add citric acid? my ferric oxide seperates from the oil when comes in contact with magnetic field

  10. Hey Ferric Oxide is very caustic and reactive if i remember correctly, dangerous stuff. Don’t let it touch your skin or breath very fine dust when dry. avoid it . or be very very careful. it can kill you.

  11. Can’t you just buy the ferric oxide? 1lb Synthetic Black Iron Oxide (Fe3O4) – 0.30 micron particle size is $10-12 on Amazon.

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Cosplayer, writer, craftswoman at Ruby Fern, and co-founder of the non-profit The Geek Foundation. I love creativity and being a maker!

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