Secure transport for N42 magnets 1

[koutetsuhane]

Is there a way to dampen or suppress the magnetic field of a N42 Neodymium magnet for safe travel without the heighten threat of flying objects or wiping computers. I know that there is no way to completely suppress the field, but slightly suppress around 10%-25% less powerful?

 

[prex]

They are normally grouped into boxes, then the boxes are covered inside all around by a carbon steel sheet, with a thickness in the order of 0.2 to 0.5 millimeters.
However this may be not sufficient for aviation regulations.
A better protection with not too much weight added is achieved by putting two layers of carbon steel sheet separated by a thickness of one to two centimeters of a packing material.
Of course the magnets must be firmly held in place by a suitable filling inside the box.

prex

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[MJR2]

A few inches of wood or cardboard around most magnets will make them safe to handle. Tape the package securely.

If you are transporting by air you will need to set them up in a very magnetically clean room with a sensitive gauss meter and experiment with shunting the field.

Mike

 

[MagMike]

In addition to prex's recommendations: Make two stacks of magnets, one with North pole up, the other with South pole up. Bring them together (carefully) so the North & South poles attract (you can add a non-magnetic spacer so the end-user can pull them apart). A substantial portion of the magnetic field will travel to the neighboring stack of magnets instead of out of the box/crate.

If you try this, it's very important for the stacks to have the same number of magnets. If one stack is longer by one magnet, lots of extra flux will travel out of the box.

If the quantity of magnets is large and two stacks is unwieldy, make 4, 6, 8, etc. stacks and stick them together (magnetically). It's important for each stack to have a neighbor.

Also, prex mentioned this but it is worth repeating: There are strict aviation regulations regarding shipping magnets by air. Each box must be tested for stray flux.

Mike

 

[IRstuff]

You can short out the fields coming out of the ends of the stacks pretty easily. I can't remember what type, but I think it's a high-Nickel steel. They can be found inside hard drives backing the head positioner magnets.

So a slab about 0.1" thick on each end will pretty much zero out the end fields with alternating poles. Then some thin sheets of the same material on the sides should eliminate the remaining fields.

TTFN

FAQ731-376