Author Options:

Magnets in the Microwave, can you do it? Answered

So does anyone know if you can put a magnet in the microwave? Will it cause some nuclear explosion, or rocket me back into time? Or will it just stay on my mug and witness the warming of my beverage?


Dr. dB

5 years ago

No, microwaving a magnet won't send you back in time... that's only if you Xerox a mirror! (Then, to get back to the future, you have to microwave instant coffee or commit some other act of flagrant redundancy.)

Sorry guys its not that dramatic. A magnet in a microwave will cause more damage to the magnet than the microwave. Seriously. Metals in a microwave are ill advised only because it ruins food. You can do some interesting things to metal with a microwave. As far as magnets go: Magnets attract and absorb the microwave radiation given off from a magnetron. Most all metals reflect microwave radiation, yet when magnetized they do the exact opposite. Magnets heat up extremely quick in a microwave and they get extremely hot as well. Anyone who knows a bit about magnets can tell you that when they get hot they loose their polarity. As the metal heats up the poles become less defined and as it cools down again the poles tend to loose coherence. You can try this at home by sticking a small magnet to the side of your microwave. With a few minutes of cooking the magnet will simply fall off. Because they attract and absorb microwaves so well you can use them to smelt metals. Try putting two small magnets on either side of a penny (make sure there smaller than the penny and that the penny isn't solid copper). Nuke em and shortly the penny will ooze like a gusher. I can do it in under two minutes with a 1.5kw microwave.

I could put a magnet in a microwave. It's not a good idea though. :)

like sticking refrigerator magnets to your computer box or monitor is not a good idea.....only the microwave may do more than just "stop working". :-)

Very possible... or at least

Pzzzzztttzzzzz fzzzzt


Wow. See? Instructables saved my life. I have one of those commuter mugs that is rigged up so you can slide a picture or something between the two walls of the cup...I have a really cool kinda flexible elephant magnet I wanted to slide in...but I microwave it, so nevermind...I guess I'll just be satisfied with it on my fridge...Thanks for all your info, everyone!!

you could scan the magnet, and print it so you could put it in the mug.... just an idea if you really want to have it in it.

At very least, it saved you from damaging the microwave. I mean, as someone stated below, if the magnet was very weak, there is a small chance that nothing would happen (with enough "food/water" in the mug) but it sure would not be worth it to ruin a good microwave over, just to find out.

Well...The microwave is great, I wish I didn't use it as much as I do, but it was the magnet I was worried about. It's one-of-a-kind. I got lucky microwaving a hologram sticker, but felt I should get a second opinion on the magnet. Thanks for your info! *I never thought I would be putting such strange things in the microwave...

I have seen stranger things put in them already.....

Wow! That was truly televisual bliss. My favorite for dramatic value was the the alcohol video, it pured out of the microwave like napalm! I also enjoyed the mewtons cradle one...explosions are always fun!

I was rather surprised by the effect it had on a candle, myself. I didn't expect that.

If the magnet is of sufficient size, you may see #1: lots of sparking before the magnetron dies #2: sparks and flame before the magnetron dies #3: an explosion as the magnetron blows it's tube and the door off the machine This is NOT advisable. Metal in very small amounts ( small ratio to any "food" in the microwave) is ok, but not really good in a concentrated area (thus those metalized coatings on some "browners" in the cartons of frozen foods we buy are ok).

A magnet could also, if strong enough, interfere with the fan that spreads the microwaves throughout the machine. danger Will Robinson !

That would cause GRAVE danger. Cold feet this winter anyone?


10 years ago

Only one way to find out, I guess...

If you're up for some experimentation, I would suggest starting with a small piece of a weak magnet - like a snippet of flexible fridge magnet, submerged in a glass of water. The water will absorb most of the microwave radiation, and will prevent any stray sparks. You may want to rest the magnet on a piece of plastic or cardboard inside the water, so it's not in direct contact with the glass, just in case...

I bet that a sliver of fridge magnet in a glass of water will probably not do anything whatsoever. Nuke it for 20 seconds (or until you notice something weird, whichever happens first), take out the magnet and check for heat (don't burn yourself on boiling water!).

If that doesn't do anything, increase the duration, until you get to the point the water starts to boil. Watch out for flash-boiling of superheated water when you take it out of the microwave!

If you don't get anything with the fridge magnet, you can graduate to more powerful magnets, and less water in the glass. Never run the microwave without *any* water (or food) in it though - that's a good way to ruin it. Make sure you have at least a glass of water next to your magnet, to absorb some of the radiation...

Most permanent magnets are primarily composed of iron, metal in general is not advisable to place in a microwave. My brother put one of my mother's china bowls with the gold etching around the rib in a microwave, it threw blue sparks. Never works quite right again, lol. (Blew several fuses in the Micro before we tossed it). All magnets (as far as I know) have at least some metal in them. Simple answer, yes you can put a magnet in the microwave. Is it safe? Not really. If you want to experiment hook up the microwave somewhere safe (ie, extension cord away from structures), and set up a camera (in case it explodes). Good rule with explosions, if you can see it, it can kill you. Have fun, and good luck. You've been warned.

Interesting question, let me go check... Actually I will have to try that, I'll grab a junker microwave from somewhere, neodyium magnets proved a confusing material to microwave, magnetite may do odd things and while Im there I'll microwave an alarm clock for the hell of it.

sounds dangerous if i had an old microwave, a magnet, and somewhere safe to test it. personally, i would do it. but i don't have an old microwave. my luck though, nothing cool would happen. then i'd be stuck with a microwave, and disappointment...

Since a (two) magnets are used to create and control microwaves, I'd guess that a weak magnet would heat up (look up microwave melting of metals, magnetite is a good microwave acceptor) and a strong magnet would affect where the 'hot spot' is, bending the microwaves away from the magnet or, depending on the geometry of the oven and magnet, focus the microwaves threw the center.

Depends: it will do 1 of two things: Nothing -- there was enough other mass to absorb the uwaves and/or it happened to just be shaped in a lucky way to not absorb any. OR Really bad -- it will get enough to be like any other piece of metal in the microwave: spark & heat up. The heating up may damage the magnet, depending on the type & how hot it gets.