A Way to Cover Powerful Neodymium Magnets




Neodymium iron boron (NIB) magnets are extremely powerful. Even moderate-sized ones can be amazingly dangerous to handle at first.

In this project I demonstrate a simple, cheap, relatively effective way to cover 2-inch (5cm x 2.5cm x 1cm) NIB magnets. This size is commonly used in home wind-generator projects.

Materials: aluminum foil, duct tape, masking tape, double-sided tape.
Tools: scissors

Step 1: Safety Precautions

Part of the reason I came up with this covering system was because these magnets are so powerful that they can easily injure you. The covering as shown makes them much safer and easier to handle (though caution is still required).

If you've had experience with NIB magnets you've already learned this, and probably the hard way: these things are very dangerous if not handled properly!

Be careful with NIB magnets of any mass...any magnet larger than a penny is definitely dangerous (and even smaller ones can be if they slam together and shatter). These magnets are sintered, which means that they are not a solid mass of metal or ceramic, but are rather compressed powder. Thus they splinter or shatter very easily.

Additionally, they are so strong that two (or more) of them can react while several inches apart, and these two-inchers could easily rip one's flesh off if they pinch together right. They will also attract iron-based metal objects from a distance: scissors, knives, or other objects will unexpectedly be attracted.

So when working with these, before you begin make sure you clear your work area of any metal objects. Work with one magnet at a time until you become very certain of your procedures. If two of the magnets used in this project slam together, there is essentially no way to get them apart without damaging them (actually I'm sure a way could be found to separate them, but it's certainly best to not let them join).

When cutting the tape off the ends there is a special technique I use to prevent letting my scissors attach to the magnet, which I will explain directly

Step 2: Gather Materials

- Standard duct tape (I used black)
- 1/4" masking tape.
- Double-sided tape (I used 3M brand)
- Aluminum foil (4" square)
- Small scissors (larger ones will be more strongly attracted to the magnet)
- Magnet (keep far away from scissors or any other metal objects, except intentional attachment)

Step 3: Wrap Magnet in Foil

The foil is simply used to prevent the tape from sticking to the magnet. The cover can then be changed or removed as desired in the future.

Wrap tightly, then pinch the ends closed. Don't pinch tightly or the foil will tear at the corners as they are sharp. The excess at the ends can be torn off carefully, or cut with scissors, leaving 1mm or so overhang that is then folded down and compressed.

To cut with scissors: grip magnet tightly in a fist so that the edge of the magnet is 2 or 3mm below the thumb-side of your closed fist. Rest the scissors against your hand...you will feel the magnet pull the scissors tightly against your hand. Keeping a firm grip on the magnet, angle the scissors slightly up so as not to cut any of your skin; cut the aluminum.

(Use this same technique for cutting the excess duct-tape in Step 6.)

*In this picture I'm a little too close to my clipboard...moving that magnet 1cm to the right would cause an unwanted attraction.

Step 4: Add Double-Sided Tape

The double-sided tape is around a millimeter thick. The small amount of distance diminishes the at-surface strength by a surprising amount (since the intensity of the magnetic field diminishes with distance according to an inverse square law i believe).

Coulomb's law?

This tape will make it easier to remove the magnet from a flat surface or dense ferric object, and will protect the surface from rapidly accelerating objects.

For some applications you may want to leave the double-sided tape off of one or both polar surfaces to maximize the magnetic field; the other layers will provide some surface protection.

Step 5: Cover One Side With Duct Tape

Cut a 12 inch or so piece of duct tape in half so that you have two pieces of equal length. Turn one piece over so the sticky side is up. Center the magnet over the duct tape and set magnet down; press for full adhesion. Leave duct tape flat.

*I wrapped the outer edge of this magnet with masking tape because the foil was a bit torn. Normally this isn't necessary. I tried tearing the foil rather than cutting it as I usually would; tearing didn't work too well.

Step 6: Place 2nd Piece of Duct Tape; Join Both Pieces. Cut Ends

While looking straight down over the magnet and duct tape, align the other piece of duct tape from above and place it on the magnet. Try not to let the ends of the two pieces of tape make contact yet - just let the tape touch the magnet. Once they have adhered well, fold up the sides of the bottom piece of tape along the long edge of the magnet; if the magnet is centered properly the tape should reach nearly to the top surface.

Fold down the long edge of the top piece of tape, and allow the ends of the top & bottom tape-pieces to meet. They may meet in a very sloppy fashion but this won't matter. Sometimes I strive to make them line up or fold over very carefully but the end result isn't much different.

Finally, cut the ends of the tape with scissors. Grip magnet tightly in a fist with your non-dominant hand so that the edge of the magnet is 2 or 3mm below the thumb-side of your closed fist. Rest the scissors against your hand...you will feel the magnet pull the scissors tightly against the circle of your thumb and forefinger. Keeping a firm grip on the magnet, angle the scissors slightly up so as not to cut any of your skin; cut the tape.

(This technique is also used for cutting the excess aluminum foil in Step 3.)

Step 7: Wrap Edge With Masking Tape

This step is mostly cosmetic. However the duct-tape join is sticky and thus the edge-wrap prevents unwanted duct-tape adhesive from getting on your hands or any objects the magnet is attached to. Definitely provides a neater and more finished appearance.

This is 1/4-inch tape and is approximately the same width as the magnet and works perfectly; I think it's from an art-supply store but it may be sold at hardware stores as well.

Step 8: Finished!

I bought these magnets for a generator project I re-considered and wondered what to do with them...they were so strong that attaching them to a flat metal surface was very problematic (if I ever wanted to get them off). They were also very prone to cracks and surface damage from attraction-impacts.

With this 5-minute covering job these are now serving as holders for things like knives and towels in my kitchen, a crowbar, various small tools, and my retractable dog leash. It's surprising how quickly they disappear as I find previously-unconsidered uses for them.

*The paper in the picture is much larger than 8.5 x 12 so the scale seems off.



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    27 Discussions

    Scientist Smith

    2 years ago

    Hello, I myself am a very young teen, and I am what people would call magneto. I am a magnet nerd. I go to a high school in Utah called Beehive Science &Technology Academy. And I'll tell ya, getting your fingers, or let alone your hand in between two 1by1 inch Neodymium Magnet of a grade N52 really hurts! I have gotten my skin sliced open with them. And I'll tell ya, it's not fun! Especially when you don't have specially made tools to pull the magnet directly off of the skin.

    If you want to learn more, or reference me in any way feel free to. I have helped thousands of people remove powerful magnets from their legs, arms, fingers, and hands. I've also posted a Neodymium magnet article at the link below for those wanting to learn a lot more about these amazing magnets and what they are capable of.

    Link: https://sites.google.com/site/neodymiummagnetsfacts/


    3 years ago on Introduction

    Wow, people need to be careful of these magnets. Someone close to me walked past a metal gate and the magnet smashed her hand up against the iron gate and bruising her finger pretty bad. And she was about 5-7 inches away from the gate just walking past it with the bare magnet in her hand. Take precautions with these things. If the magnet breaks you buy another one, you can't repair smashed or busted fingers like new people.

    As a matter of a fact, J and K magnetics has a magnet seperator they sell, and if you don't want to buy a magnet seperator, they say to put the two magnets against a door frame and push until the magnets seperate, and keep going(trust me keep pushing, it's just safer that way).


    12 years ago

    No, I mean united nuclear's magnets that many inches across. those are the ones that they tell you to plan you path through a room with them so they dont fly across the room and shatter into many peices. They affect magnetic feilds in an entire room and easily crush fingers and arm and make metallic objects shoot twards them at great distances. fun but insanely dangerous;)

    8 replies

    Reply 8 years ago on Introduction

    Hi, i want start working with this kind of super magnet , and want know have you information about them,, like they power of magnets and lifting power and something like that, i really need this info, if you can help me or know somebody who can please tell me by my email :moein_glory@yahoo.com
    im really waiting and tanx a lot


    Reply 10 years ago on Introduction

    Holy Muffin man...

    The is huge!

    You could change the place of the north and place it in the south =P


    Reply 10 years ago on Introduction

    Whatever you do don't do what I did. I bought two of these thinking they would be fun to play with. I put one in my front pants pocket and as soon as I went to put the other into the other pocket I realized that it was a bad idea. That being said and dumb, covering neo's is definitely a must which makes this a very good Instructable.

    John Culbertsonpyro22

    Reply 11 years ago on Introduction

    K and J have even stringer magnets than United nuclear, the big one pictured above is only N45 and no they are "not the most powerful" as UN claims, the scale goes to N50 which k and J just got a huge stock of like this one.

    ImperarJohn Culbertson

    Reply 11 years ago on Introduction

    Actually the scale goes to N52 and the one you have here are smaller in diameter than the other one with being held in the hand.


    Reply 11 years ago on Introduction

    I have 10 of these in my room they totally destroyed my computer and electronic equipment including credit cards


    9 years ago on Introduction

    now that they're covered, are they still harmful to credit cards, computers, electronics, etc.?


    10 years ago on Introduction

    is it better to get magnets at kjmagnetics.com or magnets4less.com?


    11 years ago on Introduction

    I found the best way to prevent chips and make these giant magnets somewhat safer is to coat them in a product called PlastiDip, which you should be able to find at a local hardware store. (It's used for coating metal tool handles with a rubberized grip)

    You'll need some fishing line or thread, and a non-magnetic container for dipping (it comes in metal cans). Give it at least 2 or 3 coats (allow several hours to dry between coats)

    For anyone who wants to buy these magnets to play with, be aware that they can be very dangerous if handled wrong, and for god's sake, if you've never handled neodymium magnets before, DON'T buy two... They are exponentially more powerful when they stick to each other. I've had my keys *embedded* in the back of my hand from careless handling of these things (broke the skin in one place and caused massive bruising). Play Safe!

    1 reply

    Reply 11 years ago on Introduction

    that is a great tip - thanks! so you tie the fishing line around the magnet, then hang it to dry, correct? what do you do with the line once you've made all the coats and it's dry - just cut it off and leave it embedded? also, does the coating tend to pool at the bottom due to gravity? or maybe you hang oriented different ways during the various coats to even that out? thanks again for the useful tip.


    11 years ago on Introduction

    hey guys i live in australia, and i cant buy off unitednuclear because i live outside of th US of A. i was wonderng if i transferred some money to someones account they could but the magnets for me and ship them to austraila.thanks

    1 reply

    Reply 11 years ago on Introduction

    i would recommend buying off of ebay; they have a wide selection and the prices are better than UN anyway. that's where i've bought all of my magnets. just do a search for 'neodymium magnetneodymium magnet' on ebay; various sellers provide quite a wide price- and size-range.


    11 years ago on Introduction

    i saw some N45 neodymium magnet rings on unitednuclear.com and no warnings are given in the ring section. N45 neodymium magnet RINGS!! am i the only one that sees the possible damage that may result from carrying a powerful magnet on your finger everywhere you go? i think they should atleast have some kind of warning


    11 years ago on Step 5

    you can cut the foil with your thumbnail by setting it down on a surface that's not completely hard like a cutting mat and using your 1st 2 finger as guides by pressing them flat against the surface, I learnt this from many things I have done in life considering my slodering iron went missing and I am a lover of match rockets the tine foil makes a great many appearances in my life