Ferrofluids are really cool. They are liquids that change properties when introduced to a magnetic field. They have been a big part of some recent research on things varying from space shuttles to body armor! Usually they are very expensive and complicated to make, but we have found a way to make a simple mid-quality ferrfluid out of household items quickly, easily and very affordably. You probably have all of the materials at home, and it can be done with little to no effort or time.
Acetone is high flammable so be careful with it. You can get it at most department stores or beauty supply shops..
Music or video records tapes. You can get these oldies almost anywhere. You probably have a few laying around your house.
Every house has secret room...The kitchen...
You can get it from any speaker in your house... Be ingenious... Or look online for some neodymium magnets.
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. It also includes some sort of dry lubricant to avoid wearing out the recorder.
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.
We need separate Ferric oxide from plastic tapes. Acetone will melt the binder and separate Ferric oxide. But first we need to smash and break tapes!
Find a big bowl. Put all tapes in it and fill the bowl with acetone. Wait few hours. You can close bowl with something for a better effect. Make sure that you are in a well ventilated area away from open flames! Acetone is dangerous- read the bottle.
4) Collect the ferric oxide
Get a magnet. Roll it with paper (paper is needed to separate ferric oxide from magnet). Collect all your Fe2O3. Let it air dry and put it in a safe place.
If all of the oxide did not separate from the tape, you can repeat the procedure with acetone few time to have a better effect.
Mix three parts ferric oxide with one part cooking oil. If it's to viscous add a drop of water and a drop of dish soap and mix everything again. It will be good.