Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

LPF Donation via Stripe | LPF Donation - Other Methods

Links below open in new window

ArcticMyst Security by Avery

20 Rare Earth Magnets for $1 (dead, now $4)






Bionic-Badger

Bionic-Badger

0
Joined
Oct 26, 2007
Messages
5,438
Points
83
Re: 20 Rare Earth Magnets for $1-great for LED thr

What I hate is how the rare earth magnets are so strong that they actually end up crushing themselves under their own magnetic field, resulting in the nickel plating cracking which causes the rare earth metal inside to corrode.

So if you get these make sure to not keep them in one big "stack" or they'll start killing themselves.
 
TheMonk

TheMonk

0
Joined
Aug 29, 2007
Messages
750
Points
0
Re: 20 Rare Earth Magnets for $1-great for LED thr

How strong are they? stronger than the magnets inside the hard drive?
 
P

phoenix3200

0
Joined
Oct 14, 2008
Messages
233
Points
0
Re: 20 Rare Earth Magnets for $1-great for LED thr

The ones inside a hard drive are neodymium/rare earth magnets.  In fact, sleds have two neodymium magnets (~2x5x10 mm) in them to help with alignment, which to me is the added bonus of getting whole sleds and not just the diodes.
 
sk8er4514

sk8er4514

0
Joined
Feb 28, 2008
Messages
1,809
Points
0
Re: 20 Rare Earth Magnets for $1-great for LED thr

yeah I've seen those magnets in the sleds and they are crazy strong. I've thought about making my own throwies out of those but never have had the ambition or time to do it.

IIRC there are 4 of those magnets in each sled.
 
D

danq

0
Joined
Sep 18, 2007
Messages
835
Points
18
Re: 20 Rare Earth Magnets for $1-great for LED thr

jwc said:
You can also get a pack of 100 for like $6, but I don't know what on earth you would do with that many...
Click to expand...
stick 'em on things? ;-)

I like these. Not as cheap at $12 for 50 - 24c each - but fun! I like to sprinkle them around town - on the sidewalk, backs of chairs, restaurants... "oh no! there's an epidemic of gold nuggets stuck to everything!" ;-)


Bionic-Badger said:
What I hate is how the rare earth magnets are so strong that they actually end up crushing themselves under their own magnetic field, resulting in the nickel plating cracking which causes the rare earth metal inside to corrode.

So if you get these make sure to not keep them in one big "stack" or they'll start killing themselves.
Click to expand...
? I've never had them self-crush while in a stack, unmoved...

but they are a pain in the butt! or can be... magnetize anything ferrous they touch, which is not always a good thing.  

And when I have them on the workbench - which is often, because I use them to hold clip leads onto batteries - I'll be moving some tool, or test clip lead, and get too close to the magnet... so as I'm moving, something gets hung up... then that brings something else into the picture, which hangs on something else... and pretty soon there's this sticky logjam that my meager 2 hands just can't deal with all at once - and if there was a powered circuit in there, well...  ::)
 
yobresal

yobresal

0
Joined
Nov 5, 2007
Messages
4,919
Points
83
My biggest mistake was buying a HUGE one of these magnets. Now whenever I get smaller ones they eventually get crushed by the force of the monster magnet.
 
D

danq

0
Joined
Sep 18, 2007
Messages
835
Points
18
yobresal said:
My biggest mistake was buying a HUGE one of these magnets. Now whenever I get smaller ones they eventually get crushed by the force of the monster magnet.
Click to expand...
that brings up a very real downside to this kind of magic:
they are very dangerous for children!
it may have been at United Nuclear (above link) where I saw the story about a young child getting his hand crushed when bringing a big one too close to another. Apocryphal perhaps, but still... caution is better than sorrow.
 
J

jwc

0
Joined
Oct 20, 2008
Messages
337
Points
0
Re: 20 Rare Earth Magnets for $1-great for LED thr

sk8er4514 said:
IIRC there are 4 of those magnets in each sled.
Click to expand...

Really? I have only found 2.
 
Bionic-Badger

Bionic-Badger

0
Joined
Oct 26, 2007
Messages
5,438
Points
83
Yes, you can get blood blisters, or even broken bones depending on how large/strong the magnets are and what falls between them. But accidents aside, the worst part is when you're showing someone else and you tell them that they are VERY strong--unexpectedly strong in fact--and they STILL underestimate the strength, and you hear the inevitable "clack" of the two magnets sticking together, and hope that neither has cracked. I would suggest dipping larger rare earth magnets in that plastic tool goop so they have some padding.

These kinds of magnets are found in hard drives, albeit the hard drive magnets are much larger than these puny disc magnets. Keep them away from CRT televisions and monitors, though you can see the screen discolor when you do bring them near.

For children, a greater danger than broken bones or pinched fingers is if they swallow the magnets. One can go into the intestine and then connect with another and rip through the intestinal tracts. It was one reason many of those toys from China were recalled.
 
D

danq

0
Joined
Sep 18, 2007
Messages
835
Points
18
Bionic-Badger said:
...and they STILL underestimate the strength, and you hear the inevitable "clack" of the two magnets sticking together...
Click to expand...
oh yeah... how many times... ::)
nowadays I'll only give 'em the magnets that are wrapped in foam padding :p

For children, a greater danger than broken bones or pinched fingers is if they swallow the magnets.  One can go into the intestine and then connect with another and rip through the intestinal tracts.
Click to expand...
I'd heard about that... and since then haven't left any on a sidewalk. I'm pretty sure though that a child young enough to just swallow anything would not be able to pull one off of a metal surface?
 
Swordofsalvation

Swordofsalvation

0
Joined
Nov 30, 2008
Messages
428
Points
18
yeah...i bought a neodynium magnet...it was so strong, it lifted a school desk half a foot off the floor, and caused me to get stuck to a metal pole because it was in my pocket!!! be careful with these magnets, they can easil do damage, especially large ones
 
You must log in or register to reply here.




Top