Neodymium itself oxidizes so rapidly that it needs to be stored in mineral oil. It also has many radioactive isotopes that would make a pure samle of Neodymium dangerous to handle. The magnets in hard drives are a Neodymium compound also containing Iron and Boron- NdFeB.
You can buy these magnets here for less than $1 http://www.indigo.com/magnets/gphmgnts/rare-earth-magnets.html

mathgeek

I heard about an artist who uses ferrofluids between two plates of glass along with some mechanically controlled magnets to make these dynamic painting type things.
How do you get ferrofluids? Do you make you own with some clear liquid and neutrally bouyant ferromagnetic metal filings? I never thought of doing that. Sounds like fun.

mathgeek

Another Tip:
I've removed a few hard drive magnets myself (they make great refrigerator magnets, and are great for magnetizing screwdrivers) and the best way I've found to get them safely off of the metal backplates they're epoxy'ed to is:
Get 2 pairs of pliars if you're using the stove, or a bench clamp if you use a propane torch as a heat source.
Now grab the backplate with one of the pliars or in the bench clamp, and use the other pair to apply a shearing force to the magnet by placing the one jaw on the side of the magnet and the other jaw on the side of the back plate as if you were going to slide the magnet on the backplate, and apply a good amount of pressure.
Now, apply your heat to the backplate while trying to keep it off the magnet, as overheating the magnet will demagnetize it.
As soon as the magnet slips on the backplate, as you're still applying the shearing force, you know that the epoxy has been overheated.
Now, as soon as it slips, hurry up and remove the heat source and immediately seperate the magnet from the back plate taking care not to scratch the chrome plating on the magnet. If the magnet stays on the hot back plate too long, the heat will begin to transfer all the way into the magnet and ruin it. After all, that's what we're trying to avoid.
Now be careful, because the back plate will be extremely hot, in excess of 900 degrees, and the magnet will be quite hot, also, although hopefully not hot enough to dissipate the magnetic charge. It's probably also a good idea to have some oil standing by to put the magnet into once it's seperated in order to cool it down quickly, but it shouldn't matter.

I've tried soaking the magnet in gasoline overnight to try and gel the epoxy, but evidently the epoxy they use on these things is really tough, because it didn't help at all.

Another way to seperate the magnet from it's back plate is to shear it off with the blows of a hammer at room temperature. I've tried this method also, but invariably, you will end up either peeling the chrome plating or cleaving the magnet in two. This surprisingly doesn't seem to reduce the strength of the magnet at all, so you can do this if you don't want to go to the effort of preserving the chrome plating. The only thing is that the surface of the neodymium is now exposed to the air and will darken and corrode over time. I've got a few of these on the fridge too because I don't feel guilty hitting them with screwdrivers to magnetize them.

Don't underestimate the strength of that epoxy!

The Lightning Stalker

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