New way of making a ferrofluid. Costs less than 3$!!!

Picture of New way of making a ferrofluid. Costs less than 3$!!!
Ferrofluid - a substance that's liquid under normal conditions, but turns solid in the presence of a magnetic field.

I found new way of making home made ferrofluid and I want to share it with you guys.

The advantage of my project is cost. It's way cheaper than all other methods online and it is indeed very simple.

My ferrofluid consist only two inexpensive parts, you only need old record tapes and a bottle of acetone!
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Step 1: Materials

Picture of Materials
ring ferrite.jpg
You will only need ACETONE, record TAPES, cooking OIL and MAGNET.

---500ml/16 fl. oz. Acetone. (1.50$)---
Acetone is high flameable be careful with it. You can get it at department store. It cost around 2$.

---10 music tapes or 4 video tapes. (0.00$)---
Use old music or video records tapes.You can get them virtually in any basement...

---5ml/0.2 fl. oz. Cooking oil. (0.00$)---
Every house has a secret room...The Kitchen...

---1 big strong magnet. (0.50$)---
You can get it from any old speaker in your house. Just take it apart and use it!


Step 2: Prepare tapes

Picture of Prepare tapes
The tape itself is actually very simple. It consists of a thin plastic base material, and bonded to this base is a coating of ferric oxide powder. The oxide is normally mixed with a binder to attach it to the plastic, and it also includes some sort of dry lubricant to avoid wearing out the recorder.

Ferric and iron oxides:
Iron oxide (FeO) is the red rust we commonly see. Ferric oxide (Fe2O3) is another oxide of iron. Maghemite or gamma ferric oxide are common names for the substance.

More info how tape work:

We need separate Ferric oxide from plastic tapes. Acetone will melt binder and separate Ferric oxide. But first we need to smash and break tapes!

Step 3: Melt binder and separate Fe2O3

Picture of Melt binder and separate Fe2O3
Find large enough bowl. Put all tapes in and fill bowl with acetone. Wait few hours. You should close bowl with something to keep acetone from vaporising.
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andytangtsk3 months ago
Fe2O3 is red rust. Fe3O4 is the thing you made, great i'ble still
grokcore2 years ago
You can't make nanoparticles out of casette tapes, sorry.
It's neat, but it's not true ferrofluid, it's some kind of ferrite suspension, but you can do something this with rust/iron filings and oil (and a really strong magnet).
Oh - but you can make it though (but expect some nasty nasty fumes)
Ironious grokcore3 months ago

This is the method I use, but use half the amount of kerosene or else too watery and wont spike.

nro.slm5 months ago

I've seen commentators on other projects note that cooking oil will go rancid after some time and recommend mineral oil. That's what I'm going to try today, hope it works! And thanks for the great write up, I never would of though of covering the magnet with plastic.

Hi, I started this method with a VHS. Then while the tape was in the acetone, I read the comments and saw that it doesn't work with VHS.

So I thrown the video tape in my BBQ and put it on fire because I was very angry.

I've lost a part of my arm hair...

Then I took the ashes and realised it could still work with it.

And it worked :D

thecrazylol11 months ago
how much ferrofluid can you make with one video tape?
nerd74732 years ago
Newty6 years ago
This does look easy. But I'm not sure I'd call $200 per cup a "very low price" when a $60 per cup result tops a Google search for "buy ferrofluid". Does this instructable produce better quality stuff? To whatnot: The dish soap is the surfactant and also emulsifies the oil and water. Apparently you can make magnetite more soluble in oil or kerosene using oleic acid, or more soluble in water with citric acid. I'm also reading a journal abstract here where they got crazy and dissolved in water particles made of magnetite+styrofoam, coated with oleic acid, surrounded by oil, coated with dodecyl sulfate.
hcaz-301 Newty2 years ago
You can buy it for about £10 per 30ml on ebay
Good comment , compliments.
beehard44 Newty5 years ago
yes, it is cheap, but you forgot onne thing, Delivery price. Maybe it is no big deal if you live in the US, but change the setting to the philippines, it's a different story...
Zujus (author)  Newty6 years ago
he he ;D This is one of my first instructables, actually it is way better to buy thing if your point is quality. ;) I made better one "Real" ferrofluid so this is very simple and basic version. But still pretty cool ;)
moris_zen2 years ago
I tried same thing but burned the tapes .. I got a lot of ferrite fluid but quality was low - Couldn't get any shape like you show in the beginning . you sure this is fluid you made this way ?
Darmago7 years ago
Could you be a little more specific on how you "magnetize" the ferrofluid, I'm a little confused at this point. Also, why does size matter and not strength for magnetizing it?
another good substance is to ask mates or uni ("borrow") finished toner cartridges! there is still always at leased a table spoon of toner powder left in them!! (toner is a magnetic ink) mix this into the substance too. it adds to the effect really well. !! dont make it too weak cause it just flops about after the magnet then !!
i didn't know that regular toner cartriges use magnetic ink a.k.a. toner...
i thought that a special toner is used for that one...
Me neither , Are you sure that toner is megnetic ? I thught it was som kind of organic. Anyway iron must be just a part of the compound
Zujus (author)  last_decoy6 years ago
Yea, there was popular instructable about that. :)
ok the way he made the ferrofluid is by putting amagnet underneath thats what he means by "magnatize" and you do want a strong magnet but you also want one that covers a big surface area so you get a big affect Cheers
-Aj-6 years ago
good idea, greae use for all those dead floppy disks and cassette tapes! can also use mentholated spirits. should work. it is abit less evil on your head + less flammable. also dissolves in water dont know if acetone does if that helps at all. im off to pilfer old video tape now!
Acetone seems to have failed to dissolve video tapes for me. Did 'mentholated spirits' work for you? If so, what are they and where can I get them? Thanks.
Acetone failed to dissolve my viideos too. I kept tapes in acetone a night long and nothing happened. Tapes were all of the same set. Acetone was clear , no iron oxide dust appeared, I guess tapes differ in some kind of wear protection. I' ll try with some other different set of cassettes. I tried to add nitro paint diluent but nothing happened. What about gasoline ?. Anyway I got rid of that junk at last.
What about tumbling mineral magnetite in a pop bottle with little round quartz stones. Quartz stones are free and harder than black magnetite that is free also.. You can collect nagnetite in many river sands using an magnet. That's just a last minute idea , I didn't try to tumble magnetite jet.
At your local bar xD
Never do this to a tape that still works. If you do, i'll be around your home tonight... Just kidding, but never use working tapes. VHS? Go ahead, they still make them.
does it have to be written over before i do that to it? i put a small strip of VHS which was a movie in there too and when i run my finger over it really hard, my finger turns a little black. the other tapes are completely new and have never been written over
magnet183 years ago
most rust is actually fe2o3, dosen't change anything, just sayin...
mrmorose3 years ago
Great idea, but it doesn't seem to work very will with VHS tapes (no clue why). We couldn't get the ferric oxide to separate from the film using acetone set for about two hours. shrug*
Same problem; audio cassettes worked fine, but I have a bucket of videotapes I could seemingly just respool and watch again. Anyone know how to do this with VHS tapes?
r-philp6 years ago
I tried dissolving the iron oxide off a video tape with acetone, but it did not work. Is the manufacturing process of video tapes different than audio tapes?
Zujus (author)  r-philp6 years ago
It could be chrome based video tape or something simply went wrong.
Same problem. I don't know if they're chrome-based vid tapes or not. They look old, standard, and cheap. I found a bunch on the street, bought a gallon of acetone, let it soak over nigh, and nothing!. ALso, wasn't clear from your instructions: Do you let the acetone evaporate before trying to harvest your ferric powder? (Not that I had anything to harvest.)

I put a lot of time and effort into this and I don't want to give up. Could it be that the room temperature wasn't warm enough? Will waiting longer help? Or do I just have to throw away the whole ugly, stinking mess?
Try using toluene.
death1923333 years ago
Just spit balling here, but wouldn't used hand warmers work? They use iron powder that then oxides and produces heat. Thus spent ones contain mainly iron oxide with a small amount of impurities.
kretzlord3 years ago
I made similar stuff with silicon oil and some magnetic powder that came with a laser printer service kit, its called developer. Worked out pretty cool, was able to get some nice effects. best of all, no acetone required
Have someone tried other than edible oil? Like motor oil...
thank you
Frankiescou4 years ago
How much Fe304 Do you need for 1 ml? I need a bigger amount of ferrofluid and its for my science fair project.
Please Reply. (I got tons of Fe304 and vegetable oil).
can u use nail polish remover?
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