How to make strong magnets?

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

Reply to
siliconmike
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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,
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Reply to
Joe Soap

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...

Reply to
Nikolas Britton

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

Reply to
Yukio YANO

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.
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When you hear the toilet flush, and hear the words "uh oh", it\'s already
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Reply to
Impmon

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

Reply to
Jonathan Kirwan

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

Reply to
CWatters

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

Reply to
spudnuty

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