How to make strong magnets?

May 26, 2005 10 Replies

I would appreciate if anyone can advise as to how to make magnets. I have an electronic engineering background, but have never done this before. I want to make tiny magnets, say size of 4mm x 4mm or 6mm x



6mm, of the power of 4000 to 5000 Gauss (higher the better)..

What material should I use ? What coating should I do on that material for corrosion protection ? What would be the thickness of the coating ? Should I do coating before / after magnetizing ? What would be the coil / dc power setup ? How do I measure the strength afterwards ?



Any advise would be great.



Thanks Mike



In response to what siliconmike posted in news: snipped-for-privacy@z14g2000cwz.googlegroups.com:

Search ebay for neodymium

Joe Soap. JUNK is stuff that you keep for 20 years, then throw away a week before you need it.

My wife buys 4mm R/E magnetic clasps for her Bead work. Don't know strength but sure beats the older styles for grip. Test by loading the clasp and note total weight required to uncouple the clasp.

Yukio YANO

Find some dead hard drives and pull the magnets from them. I don't know what kind they are but they are very powerful, keep them very far way from credit cards... I found that out the hard way! Hold them up into a fluorescence light ballast, they will easily pick up the 60Hz hum and quiver in your hand like theres no tomorrow.

The motors in the drives are rather powerful too...

Reasonable advice. I haven't pulled any from hard drives, but I have pulled them from old (dead) CD-ROM drive heads. And they are pretty nice! About .22" x .29" x .12" in size. And very strong.

Jon

I got a few out of old 5.25" full height drives. First time I let the

2 pieces get close together with my finger in between, I had black and blue bruise for several days. Bring it within a foot of CRT (TV or monitor, doesn't matter as long as it is CRT) and you get multi-colored lava lamp impression.
When you hear the toilet flush, and hear the words "uh oh", it's already too late. - by anonymous Mother in Austin, TX To reply, replace digi.mon with phreaker.net

Model flyers rewind them and use them to fly small RC model planes.

Check out this source:

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and this forum:
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especially the indoor and microflight. search for magnet sources, out runners. Richard

Pardon my comment, but why on earth would you want to make specialty, rare-earth magnet yourself when there are very wel qualified companies with vast experience at the process? Sounds kin of like wanting information on how to make an integrated circuit i your basement

I am an inveterate Do-It-Yourselfer, but there are limits. You ar

unlikely to save money by trying to make magnets at home. I requires knowledge of and sources for the specific, exotic material and the appropriate mix/alloy for the properties you want, sinterin furnaces, dies and presses, precise temperature control, ability t apply the correct magnetic field while the material is above th Curie temperature, specialty coatings and ability to bake them o (if you use powder coatings) without depolarizing your magnet, etc. etc

"Physics Today" 2003 Buyers' Guide lists a dozen or two magne

manufacturers. Go to

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select (M)agnets permanent (or the category you want), and you get the list

"magnets, permanent" brings up

Angstrom Sciences Inc.

Dexter Magnetic Technologies Inc. Global Equipment-Magnetics Division Integrated Magnetics MagnaPlan Corp. Magnetic Component Engineering Inc. Magstar Technologies National Imports LLC TeachSpin, Inc.

One or more of them may even have what you need as a standard item i

their catalog, or at least have dies to make what you need.

Good luck

awrigh

What's that Lassie? You say that siliconmike fell down the old sci.electronics.misc mine and will die if we don't mount a rescue by

26 May 2005 03:13:16 -0700:

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Dan

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