Stacking magnets

[Ozoned]

I have a lot of small rectangular magnets that are 1" x 2" x 1/2". I have built a case to hold all of them and to turn them into one large magnet. How do I stack them for maximum strength? Do I just stick them all together, or is there a special arrangement for this? The inside dimensions of the case will be 6" x 48" x 1 1/2". The case is built entirely of 14 gauge stainless steel and one exterior surface of the case will be used for scalping metal from grain.


Thank you.

 

[Artofkicking]

Magnets, as you may know, have an invisible field of magnetic "currents" which surround them. This field is what attracts ferrous matials to it (or it ti the metal). I am not totally sure, but I think that "stacking" the magnets will only provide an extra pull if the lines of force (the magnetic field) from each magnet reaches the object to be attracted. In other words, if the field from say the 4th magnet don't reach the object, then it will only be attracted to the 3rd magnet.


P.S. The magnets will let you know how they which to be stacked North to south....

Also, if you have an old crashed hdd, they have some really strong magnets in them.

 

[TuxDave]

I would say stack them. If I pull together whatever's left from my physics knowledge, I have an idea that stacking magnets is like loops in an inductor. If you assume very little flux leakage between the loops (or the magnets in your case), the flux will be additive until the very end, thus creating a stronger magnetic field. I need silverpig or drpizza to verify this for me.

 

[Dinominant]

I have about 80+ Hard Drive Magnets stuck to my wall right now, these magnets are pulling the screws out from under the paint! anyways, after about 20 stacked on top of each other, they didn't really get noticeably stronger (I just ended up having more ). After they started loosing streignth, I "folded" the tower in half. My goal is to move the north pole to my bedroom. BTW, keep these magnets FAR away from computers; my stack will effect a CRT from 1m away.

I have successfully formatted a 120GB Maxtor in 2 seconds with these magnets. It no longer works.

Dinominant

 

[oldman420]

i think that if you were to put them all stacked together in the way they stick best and then place them in strong ferrous case it would act as one huge magnet

 

[DrPizza]

Hmmmm.. I've only done minimal work with magnetic fields during the past few years.. But, from my observations, I believe that Artofkicking may be correct.
If I knew where my magnets went to, I'd test the idea right now..

But, since I don't know where mine are off the top of my head.. (but strongly suspect my children have something to do with their absence), I'll just suggest to you to figure this out experimentally: Take one magnet.. bring it closer to a paper clip. Note the distance away at which it will finally attract the paper clip. Now, repeat this with 2 magnets.. then 3, then 4. At some point, I suspect, you'll observe that no matter how many more magnets you add, the distance at which the paper clip is attracted will not increase.

And, if you want some REALLY strong magnets, get some of the neodymium magnets (can be found from several online retailers, and easily found on Ebay)
Magnets are fun toys...
Larger, stronger neodymium magnets are far from toys - you WILL get hurt if you're not careful with them.

Also, if you're willing to do a little bit of work, you might consider making an electromagnet.

Regardless, get a pile of small neodymium magnets.. they're a load of fun to play with!

Oh, and a warning that everyone seems to overlook... if you're playing with neodymium magnets.. even the tiny little ones... DO NOT PUT THEM IN YOUR POCKET THAT YOUR WALLET IS IN!! I have erased every magnetic strip on every credit card, license, etc that I have. Keep them away from the computer monitor.... one neodymium magnet a few inches from the monitor can result in hitting the degauss button approximately a bazillion times to clear up the screen. They make cool fake piercings, but don't pretend that your septum (middle of your nose) is pierced by putting to magnets on opposite sides... otherwise, you'll swear that they magnets ARE piercing your septum from the force they exert on each other... BIG ouch!!!

 

[TuxDave]

Originally posted by: DrPizza

But, since I don't know where mine are off the top of my head.. (but strongly suspect my children have something to do with their absence), I'll just suggest to you to figure this out experimentally: Take one magnet.. bring it closer to a paper clip. Note the distance away at which it will finally attract the paper clip. Now, repeat this with 2 magnets.. then 3, then 4. At some point, I suspect, you'll observe that no matter how many more magnets you add, the distance at which the paper clip is attracted will not increase.

Although I doubt any of us have sufficient equipment to do this, I suggest this as an addition to the experiement. Take a stack of two magnets and measure it's relative strength at some distance. Then remove the bottom magnet and remeasure. Replace the bottom to exactly where it was before, and remove the top and remeasure. If my theory that the stack of magnets help 'tunnel' magnetic flux through the core then this is what you should get.

The strength of the stacked magnets at some distance should be stronger than the strength of the individuals added together.

 

[Shalmanese]

Magnetic flux decrease as the 4th power of distance so it could just well be that by the time you've added the nth magnet, it's too far away to affect your object.

 

[tinyabs]

Originally posted by: Dinominant
I have successfully formatted a 120GB Maxtor in 2 seconds with these magnets. It no longer works.

Dinominant

You need a magnet that can suck iron out of your body in order to format a harddisk.

 

[Dinominant]

Originally posted by: tinyabs

Originally posted by: Dinominant
I have successfully formatted a 120GB Maxtor in 2 seconds with these magnets. It no longer works.

Dinominant

You need a magnet that can suck iron out of your body in order to format a harddisk.

I did swipe the drive a few times with about 50-60 of them stacked together (on purpose, not by accident). I have no way of testing the drive, but they certainly broke it, I know that much. I originally thought that the drive was bad to begin with, but only after I made it worse did I find out it was the controller . Of course, I'm not willing to keep these things close enough to my body to find out, I wouldn't be surprised if these magnets could do just that.

 

[DrPizza]

Originally posted by: tinyabs

Originally posted by: Dinominant
I have successfully formatted a 120GB Maxtor in 2 seconds with these magnets. It no longer works.

Dinominant

You need a magnet that can suck iron out of your body in order to format a harddisk.

Are you implying that formatting a disk involves a magnetic field strong enough to suck the iron out of your body?

 

[tinyabs]

Originally posted by: DrPizza

Originally posted by: tinyabs

Originally posted by: Dinominant
I have successfully formatted a 120GB Maxtor in 2 seconds with these magnets. It no longer works.

Dinominant

You need a magnet that can suck iron out of your body in order to format a harddisk.

Are you implying that formatting a disk involves a magnetic field strong enough to suck the iron out of your body?

A magnetic field like that will certainly ruin a harddisk. Just that someone wrote this in this forum some time ago.

 

[tinyabs]

I got very strong neodymium magnets when I was young. I used to crush the ants and little meanies with it.

Stacking them up appear strong but not 2 times stronger.

 

[Calin]

The external magnetic field will "close" much better thru metal things, the iron that is the core of a electromagnet transmit the magnetic field like 1000 times better than the air. This is the reason why in electromagnetic machines (electric motors, generators and so on) the magnetic parts fit so well. 1mm of air in the magnetic circuit is just as worst as 1m of iron.
To improve the "magnetic power" you could build a horseshoe like enclosure (you know, like in Tom and Jerry or something). Use iron blocks to cover the corners. This would improve the magnetic power at the two "open ends" while decreasing it at the rest of the circuit. You should know that a ring of magnets, aligned all north to south won't attract anything ferrous on the sides.
One more thing, you will attract only iron from the grains (no rust, no copper, no lead and so on)

Calin

 

[Calin]

Originally posted by: Dinominant
I have about 80+ Hard Drive Magnets stuck to my wall right now, these magnets are pulling the screws out from under the paint! anyways, after about 20 stacked on top of each other, they didn't really get noticeably stronger (I just ended up having more ). After they started loosing streignth, I "folded" the tower in half. My goal is to move the north pole to my bedroom. BTW, keep these magnets FAR away from computers; my stack will effect a CRT from 1m away.

I have successfully formatted a 120GB Maxtor in 2 seconds with these magnets. It no longer works.

Dinominant

I suppose the magnetic field just dealigned something inside the hard drive, or something. You couldn't do permanent damage to the disks themselves, maybe some mechanical things were "broken".
Anyway, for the hard drives with iron-containing enclosures, that will protect them from constant external magnetic fields, unlike the drives with aluminium enclosures

Calin

 

[Dinominant]

I do have some older >1GB Hard Drives. I'll have to remove a platter, swipe it a couple of times (without touching it), and put it back in. I wonder how durable hard drives really are...

As for the 120, maybe i did just damage some circuitry. But I do know for a fact, that before it worked, and after it didn't. Oh yeah, I swiped along the label, (the top aluminum cover) so I doubt that the drive was protected. If you take any magnets out of a hard drive, you'll notice that they are shielded by two metal plates, so when the magnets are in the drive, they do not interact with anything but the arm itself.

 

[Ozoned]

I have tried the stacking in two different ways. One was with the entire bundle with each row and column sticking to each other. The other was with each row stuck together and columns opposed.
Column opposed showed a little more strength.
The last set-up was with rows and columns sticking to each other with a 1/4 inch thick steel plate at the opposite side of the magnet that will do the work. With no technical tools available to measure the force, it would only be a guess, but the strength was at least double, if not more with this arangement and the addition of the steel plate. I am not sure why this happens, but I did see the same type of steel set-up on many manufactured plate magnets. I did however have to modify my case for the addition of the steel plate.

Thanks to all for the suggestions.

edit; If you want to have some fun some time, enclose several magnets inside of a stainless case and then try to weld a lid on the enclosure.

 

[Calin]

If you take a linear magnet, then the magnetic field lines that exists into the magnet will close thru the exterior air. However, a steel (or iron) bar will transmit the magnetic field 1000 times better than the air. You could see this effect as "channeling" the magnetic field. Imagine that the exterior air has electric resistance, and the magnetic field is no different than electricity (a voltage). This way, a small "magnetic" resistance (the iron bar) will channel most of the magnetic field. Also, as the "magnetic resistance" decrease (as the iron bar conducts better the magnetic field) the intensity in the circuit will increase.
There are also magnetic materials with a max limit of magnetism (the magnetic field inside them will increase linear with the power of the magnet, and then will level at a limit. These materials can be used in a transformer to limit the max voltage (the sinusoidal current entering the transformer will generate a signal like a sinus with the peaks leveled). I had a voltage regulator for the TV, long time ago.
I don't know the names for the "magnetic resistance" and related terms even in my language, so no hope to tell you the english ones. But these things are taught for electric machines in high schools (an engineer in electric machines could help?)

Calin

 

[BespinReactorShaft]

Originally posted by: Dinominant
I have successfully formatted a 120GB Maxtor in 2 seconds with these magnets. It no longer works.

You Da Man....

Question also: How exactly does "magnetic shielding" work? Is it some kind of enclosure made of a specific metal (e.g. aluminium) that prevents magnetic fields from penetrating in? Pardon my cluelessness, but I never thought magnetic fields can be stopped at all. Come to think of it, why are some metals "magnetic" and some not?

 

[TuxDave]

Originally posted by: ming2020

Originally posted by: Dinominant
I have successfully formatted a 120GB Maxtor in 2 seconds with these magnets. It no longer works.

You Da Man....

Question also: How exactly does "magnetic shielding" work? Is it some kind of enclosure made of a specific metal (e.g. aluminium) that prevents magnetic fields from penetrating in? Pardon my cluelessness, but I never thought magnetic fields can be stopped at all. Come to think of it, why are some metals "magnetic" and some not?

I don't think you can just terminate magnetic fields. If anything, you can redirect them towards a different direction using cores or simply another magnet to 'push' the fields away.

 

[BadThad]

Originally posted by: TuxDave

Originally posted by: ming2020

Originally posted by: Dinominant
I have successfully formatted a 120GB Maxtor in 2 seconds with these magnets. It no longer works.

You Da Man....

Question also: How exactly does "magnetic shielding" work? Is it some kind of enclosure made of a specific metal (e.g. aluminium) that prevents magnetic fields from penetrating in? Pardon my cluelessness, but I never thought magnetic fields can be stopped at all. Come to think of it, why are some metals "magnetic" and some not?

I don't think you can just terminate magnetic fields. If anything, you can redirect them towards a different direction using cores or simply another magnet to 'push' the fields away.

Yes, you can only control a field with another field.