FAQ - Frequently Asked Questions
Can I send magnets by mail?
Yes, if you package them appropriately. You have the following options:
- Arrange magnets antiparallel
- Increase the distance between magnets and package
- Shield magnets with iron sheets
Table of Contents
If you airfreight the package, you need to adhere to strict rules. See airfreight.
If you send the package with regular mail, the rules of the postal service apply, which are different in every country. Some don't even have regulations regarding the shipment of magnets.
Nevertheless, we recommend considering a few rules, since improper packaging can lead to shipping problems. You could damage items in other packages (credit cards, hard discs, monitors, etc.) or cause disruptions with the sorting machines of the postal service. Your package could also get caught on a metal piece and content could be pulled out.
To avoid such damages you should package the magnets appropriately for shipping. You have three possibilities that you can apply separately or combined:
Arrangement of magnetsIf you send several magnets together you can massively reduce the magnetic field through the proper arrangement of magnets within the package. Two or more magnets should be arranged in a way that half of the magnets are parallel to the other half, the poles pointing in opposite directions.
For instance, if you want to send 50 disc magnets with a diameter of 10 mm and a height of 3 mm, these basically arrange themselves into a "bar" of 50 x 3 = 150 mm length. However, you should not ship this bar like that, but break it up in the middle, so that the north poles of 25 magnets point into one direction and the other half lays parallel to them, but with the north pole pointing in the other direction. This way, the magnets will be "short circuited" and the magnetic field of the package will be almost zero. Naturally, you can arrange four, six or more "bars" parallel to each other.
If you only have 2 magnets to send, it is possible that this arrangement is not stable, meaning that the magnets don't want to stay in this anti-parallel position. You can arrange the magnets on a piece of metal sheet - one magnet with its north pole towards the metal sheet, the other one with its south pole towards the metal sheet. This way, the magnets can be stabilised and the magnetic "short circuit" is even better with the metal sheet, meaning the magnetic field will decrease massively.
The magnetic field of a magnet decreases with increasing distance very quickly. Therefore, it is advisable to pack a rather big package and position the magnets in the middle of it. It doesn't matter if you fill up the space with paper, Styrofoam, bubble wrap, cardboard or wood. Except for sheet steel, other materials are no barriers for magnetic fields. Only the increased distance is responsible for the reduction of the magnetic field.
Of course, you'll have to retain the magnets in the middle of the package, so they won't travel towards the sides of the package during the course of the transport. Therefore, the shipping of bigger magnets in an envelope is not advisable, since the distance to the outer surface is too small.
Shielding with sheet steel
If the "cheaper" methods of neutralisation or oversized packaging are not sufficient, you are left with utilising sheet steel for shielding. Sheet steel can be bent around a big magnet. It is not necessary that the sheet and the magnet touch each other, but it is important that the sheet steel induces a "short circuit", meaning that it reaches from the north pole to the south pole of the magnet. If you only place a sheet on the north pole and another one at the south pole and the sheets are not connected, this doesn't produce any shielding. The ideal shielding constitutes a box of sheet steel that totally encompasses the magnet. The stronger the magnet and the more complete the shielding should be, the thicker the sheet steel would have to be, so it does not reach a magnetic saturation and can induce a "magnetic short circuit".
Paper clip testIn order to check if a package is not overly magnetic, its surfaces would have to be measured with a teslameter and an acceptable critical value would have to be determined. This is often not possible. An every-day-life test is the paper clip test:
You put a paper clip to all sides of the package and it should not stick, but fall down. If you want to be even stricter, you can hold the surface not upright but at an angle of e.g. 45 degrees and see if the paper clip slides over the entire surface. If this test is successful, you should not have any problems during transport and the package should arrive safely without getting caught or damaging other items.
Shipping of different magnet typesDuring transport, these minimum distances between the different magnet types need to be observed to prevent damages and mutual demagnetisation:
|Ferrite||-||22 mm||0 mm|
|Neodymium||22 mm||-||43 mm|
|AlNiCo||0 mm||43 mm||-|