Need basic construction details to build storage container with flux shielding for small magnets.

[ToddB66]

Hi !

I have (4) rectangular-shaped magnets that appear to be made of compressed powdered-iron. They all measure 1.875" L x 0.875" W x 0.375" H. I recovered these out of some old discarded plastic pin-holders from my wife's sewing room and thought they might come in handy for a science project or other.

I would like to build a storage container with flux shielding for these magnets. I have searched the Internet extensively for basic construction details and in doing so, have acquired quite a bit of knowledge about magnetism and flux-shielding materials. However, even after watching many YouTube videos and reading several dozen website articles on the subject, I have not come across detailed information on the construction of a storage container with magnetic flux shielding.

I did find out that magnetic lines of force (e.g. the magnetic field) cannot be totally shielded or stopped and will always return to the opposite pole. However, the field can be re-routed into and out of a shielding material before it returns to the opposite pole. This fact provides the possibility of building an enclosure that will subdue most of the magnetic force field from getting outside of the storage container and causing damage to electronic equipment or other items that are affected by magnetism. While there are shielding materials on the market like Magnet Shield which has a high permeability number of 4000 and others for applications requiring high protection shielding materials, they are more expensive and for my application soft steel or iron being economical in small sizes will suffice.

Permeability: the property of a magnetizable substance that determines the degree in which it modifies the magnetic flux in the region occupied by it in a magnetic field.

Any help will be appreciated !

Thanks,

ToddB66

[6666]

All you need to do is put the magnets in any type of big enough box to have a physical separation from any electronic equipment and those evil magnetic lines of force , use a compass to test.
If you want to see the lines of force just use iron fileings and a piece of paper.

[Funfinder]

Thanks for the info.
What counts is the magnetical field strenght and how thick is the shielding material of the box.
Another method is to "shortcut" permanent-magnets with big enough iron pieces but most of
the time you only need enough distance.
I am using some very powerful but small and flat magnet from an old harddrive
to clean out digging holes full of very small and or rusty iron parts.
Yaming around the hole and the magnet is full of even powder-small pieces
which no pinpointer ever would detect.

btw. the disks of harddrives also have to be secured from too strong EM-fields
and loud music or ground (body) -noise-vibrations and the enclosures often just are
made of pretty thin metal.

And another interesting thing:
Its possible to communicate with RFID chips even if they are inside a closed metal-box.
And just a very thin alu-foil will not shield reliable passports etc. with such chips inside.

I wonder if its possible to detect noble metal if its inside a fully closed iron-box.
Usually not because of the eddy-currents coming mostly from the surface.

[Qiaozhi]

I would like to build a storage container with flux shielding for these magnets. I have searched the Internet extensively for basic construction details and in doing so, have acquired quite a bit of knowledge about magnetism and flux-shielding materials. However, even after watching many YouTube videos and reading several dozen website articles on the subject, I have not come across detailed information on the construction of a storage container with magnetic flux shielding.

Hi Todd,

This might seem a stupid question, but (if the magnetism is a problem) why don't you simply build the container out of something non-magnetic?
What are you wanting to store in it?

[Orbit]

Of course himself of magnetic storms, lead protects against radiation, box of of lead half a meter walls and enjoy ,magnetic force destroying magnetic force !

[Koala]

Big strong magnets normally don't cause any problems. I have a large guitar amp with a very large ceramic magnet in the same room as my electronics as well as some neodymium magnets stuck to the front of a meta self that holds my computer.


if you make cabinet out of steel I don't see how you can test it easily. A compass sill be attracted to it even without any magnets in it.



The strong field is fairly close to the magnet. You could put them in the centre of a polystyrene cube inside a metal filing cabinet.

[Funfinder]

Creating a generator environment also should weaken the field-strenght
because the magnetical field-lines then must interact with the electrons
inside of the copper-coils.

But I guess the most effective solution is to shortcut it with a
second magnet of the same shape and size. plus to minus and minus to plus.

btw. some scientists claim that the spin of the electrons creates the magnetism.
If thats right if would be some very special centrifugal-powers which creates
special force-lines inside of the time-space continuum. I find it still fascinating
and wikipedia is far away from explaining how magnetism really works and why it
can attract almost magically distant stuff. Electrostatic magnetism also is interesting.
A heavy mountain-thunderstorm can make the hairs going wild into direction sky.

[ToddB66]

Need basic construction details to build storage container with flux shielding for small magnets.

Greetings !

Note: The addresses below are both hyperlinked (just click-on to display pages.).

I believe the following website page address will help to explain how shielding material would work as an enclosure to subdue the field lines of a magnet. http://www.lessemf.com/faq-shie.html

When you arrive at this site page, look at the FAQ list on the left and click-on "Why can't I just use Lead or copper or aluminum foil for magnetic shielding ?" (at bottom of list.).

Also, you may have to scroll to the right to move the page left and see the first diagram of a magnet inside of a tubular shield, showing the field lines traveling through the tube walls and returning to the opposite pole of the magnet.
__________________________________________________ _______________________________________________

Here's another good website page address with an animated display that should help to understand magnetic shielding. https://www.kjmagnetics.com/blog.asp...ding-materials

When you arrive at this site page, scroll down to the sub-title "How thick should my shield be?"
__________________________________________________ _______________________________________________

Hope this helps !

ToddB66

[ToddB66]

Need basic construction details to build storage container with flux shielding for small magnets.

Hi !

Following is an addendum to my previous post #8.

As you can conclude from the animated display at this address: https://www.kjmagnetics.com/blog.asp...ding-materials , showing how the variation of shielding material thickness affects the magnetic field, e.g. as the thickness of the shielding material is increased, more of the magnetic field is attracted to the shielding as a more economical pathway or conduit than air for returning to the opposite pole.

Note: When you arrive at the site page, scroll down to the sub-title "How thick should my shield be?" to see the animated display.

ToddB66

[Funfinder]

Informative page, thx.

> "Why can't I just use Lead or copper or aluminum foil for magnetic shielding ?"

This reminds me of those guys who think that alufoil-hats will protect them from "evil" radiation!
Depending on the wavelength the rays also will come from below and reflect inside of the hat!


btw. making a magnet rotating ultra-fast also may eliminate its force
because that way plus and minus might "cancel" each others.
But how to make a magnet spin 360° into all directions and also super fast?
Heating and deep-freezing is another question - everything not practical for
normal usage.

The magnets at a smaller iron box which is inside of a bit larger iron box
should work ok in most cases. Some usual money-cassette per instance.

[Davor]

It works fine with superconductors.

[ToddB66]

Thread Sub-title : Making a Flux Shield Storage Container for My Magnets.

Hi !

After compiling my research information from the Internet, I've come to the following conclusions on how to build my first prototype flux shielding container for storing the magnets described in my post #1.

SHAPE: Although a perfectly round spherical (ball) shaped hollow container would be ideal, it would be difficult to make, so the next best design would be a closed cylinder.

Material: Steel or iron thick enough to provide sufficient saturation to subdue and contain the major portion of the magnetic field is required (Very difficult and expensive to subdue magnet lines of flux 100%.). Steel or iron will be more economical than professionally made flux shield materials depending on the application requirements. Testing is required.

Container Dimensions: Theoretical study suggests that for good shielding properties the optimum ratio for inside and length dimensions of a cylindrical shield would be 1:10, e.g. where the inner diameter of the cylinder = 1" and the length = 10", although in practice other ratios have proven as effective.

My prototype container: I've decided to start by using schedule 80 black iron pipe (alternately steel) with male threads at both ends, 1.5" I.D. x 1.900" O.D. x 10" L x .200" wall thickness and screw-on end caps at both ends.

Note - I decided to use a 10" container length as an alternate for the prototype, since the 1:10 ratio would result in a length of (1.5 x 10) = 15"L, which would be much longer than I need at the moment. I can always add a coupling and another piece of threaded pipe to increase the container length for further experimentation if needed. If this still doesn’t provide enough shielding, then I’ll make a larger cylindrical container, with thicker walls, to house the first prototype and re-test.

Testing the container: Since I don't own a Gauss meter and they are expensive, I will use an inexpensive oil-filled compass to estimate the shielding effectiveness of the container. The test steps will be as follows:

#1..First, I will station the compass on a flat level surface. Then with the magnets laying on this surface about 2" away from the compass, I'll slide the magnets right and left, observing the response of the compass needle. By "response" I mean quickness and speed. The compass stays in one position during the test. This will render baseline information to compare with results from the next step and of course I’ll make notes of my observations proceeding through these steps.

#2..Next, I'll insert the magnets inside of the prototype container, having placed thin wooden strips around the magnets to wedge and hold them central within the pipe I.D. and also prevent them from sticking to the inner-surfaces of the container. I'll push the magnets/wood wedges assembly to a position midway between the ends of the container and then cap the open end.

#3..Then, I’ll use a previously-made “container test cradle” (pine board with end blocks having vee-cuts.) to provide for rotation of the container, with the compass stationary at various locations underneath and then compare these compass needle responses to my notes from step #1.

ToddB66

[ToddB66]

It works fine with superconductors.

Davor,

Assume you're joking, Ha!, Ha!

ToddB66

[ToddB66]

Need basic construction details to build storage container with flux shielding for small magnets.

Informative page, thx.

> "Why can't I just use Lead or copper or aluminum foil for magnetic shielding ?"

This reminds me of those guys who think that alufoil-hats will protect them from "evil" radiation!
Depending on the wavelength the rays also will come from below and reflect inside of the hat!


btw. making a magnet rotating ultra-fast also may eliminate its force
because that way plus and minus might "cancel" each others.
But how to make a magnet spin 360° into all directions and also super fast?
Heating and deep-freezing is another question - everything not practical for
normal usage.

The magnets at a smaller iron box which is inside of a bit larger iron box
should work ok in most cases. Some usual money-cassette per instance.

Funfinder,

You're welcome ! (for the "informative page").

Thanks for laughs and the suggestion in your last paragraph !

Do you think my idea in post #12 re "Making a Flux Shield Storage Container for My Magnets." will work ?

ToddB66

[6666]

My prototype container: I've decided to start by using schedule 80 black iron pipe

Before you put the magnets anywhere near the metal pipe test to see what influence just the pipe by itself will have on the compass
as its oil filled it will be a little slower to react, even a steel bottle cap or a AA battery will skew a compass.