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My children always leave silverware in the microwave and all of my microwaves stopped working. Is there a microwave if you accidentally leave silverware in that will not cause sparks?

esther
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    Not an answer, but important: "all of my microwaves stopped working" is a relatively lucky outcome. If your children regularly put metal inside the microwave oven, it could easily result in a house fire. – Stef Jan 07 '24 at 14:27
  • Whether you see sparks or not you're still damaging the magnetron. Look into a June, which everything except a microwave. Then they can just burn themselves instead. https://juneoven.com/ – Mazura Jan 07 '24 at 15:33
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    Have you investigated whether it is due to negligence because kids are kids, or intentional because watching sparks is fun? – PTwr Jan 08 '24 at 07:37
  • No microwave but there are other types of ovens such as steam-driven which do not have this issue. – JimmyJames Jan 08 '24 at 15:50
  • It may be worth getting someone good at appliance repair to look at them and figure out in what way they "don't work". I have a 2009-vintage microwave where several cheap components have failed over the last 14 years or so. Every of those components was under $10 - a thermal switch failed open, the capacitor failed short, and the rectifier diode has failed open. Even a magnetron replacement is cheap if someone at home can safely replace it. – Kuba hasn't forgotten Monica Jan 08 '24 at 19:02
  • @Mazura Sparks indicate extreme RF load impedance mismatch. Metal that doesn't spark is of no consequence. And even then, the concern is the magnetron's glass envelope (very little of it) heating up so much that it loses vacuum and the magnetron stops working. The cathode is heated and doesn't care, and the anode is a big chunk of copper with air-cooling fins on the outside. A little bit of sparking shouldn't kill it anytime soon, at least not in my experience. – Kuba hasn't forgotten Monica Jan 08 '24 at 19:06
  • Why do microwave ovens, with metal walls, not blow up? Right... the chunk of copper doesn't care. The plastic tho: "tried to cook a burrito wrapped in aluminium foil ... plastic lining of the microwave ... melted. Despite the damage, the microwave remained functional." – Mazura Jan 08 '24 at 19:21
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    Consider that the manual almost certainly warns against putting metal in the microwave, and that it's unlikely that the manufacturer's insurers will pay out if something goes wrong when an oven is abused. Keep doing this and you are at risk of losing your house- and possibly your family. Your problem: fix it. – Mark Morgan Lloyd Jan 09 '24 at 08:52
  • @Mazura I looked at that June Oven... are they serious about the prices? Maybe when they have an 80% off sale... – End Anti-Semitic Hate Jan 10 '24 at 03:13

6 Answers6

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The sparks you describe are inherent in the microwave technology. There isn't any microwave oven that can avoid the sparks. Worse, there is a risk that the microwave will fail in a way that's way more dangerous to silently stop working. So, if you want to have a microwave oven, you absolutely have to make sure it will be used without metal inside.

As a side note, by asking about a microwave "without sparks", you're looking for a technological issue to a social problem, and such strategies usually don't work. You probably need to address the problem at a different level, together with your family.

rumtscho
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  • No metal inside at all? I've been using an old (25+ years) Bosch microwave oven for two years now, and I always leave the (iron?) baking rack inside to keep the food in the middle. (It does not have a rotating glass plate at the bottom, like my previous one.) I never noticed anything wrong ... – Glorfindel Jan 08 '24 at 17:40
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    there is a risk that the microwave will fail in a way that's way more dangerous to silently stop working I'm an engineer, and would love to hear about this failure mode. Seriously. – Kuba hasn't forgotten Monica Jan 08 '24 at 19:07
  • @Kubahasn'tforgottenMonica I've heard of microwaves blowing up because of metal forgotten inside. Is this a myth? I admit I haven't seen it happen myself. – rumtscho Jan 08 '24 at 20:41
  • Small amounts (in comparison to the quantity of food/liquid) of metal in the microwave are OK and sometimes even recommended. It is often recommended to leave a (tea)spoon in a body of liquid when boiling to "help" the formation of bubbles and avoid "flash boiling" when removed (if the liquid is super-heated). You can wrap small parts of the food in aluminium/tin foil to prevent over cooking or accidental cooking when defrosting. @Glorfindel – MrWhite Jan 08 '24 at 22:07
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    @Glorfindel, you can put metal in the microwave under the right conditions, but figuring out the right conditions requires a degree in the subject. It's far safer just to tell everyone "no metal". – Mark Jan 09 '24 at 01:38
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    @rumtscho, it should be possible to design a microwave that can detect the sparks and shut itself off, just like how my microwave can detect that it's being run empty and shut itself off (also a dangerous situation). – Mark Jan 09 '24 at 01:41
  • @Mark Computing out the exact behaviour of an arbitrary shape in an arbitrary rotation requires some significant electromagnetics and mathematical knowledge. But using metal for various purposes in a microwave without destroying anything is fairly simple. A bag of microwave popcorn for example has a piece of foil in its bottom to concentrate the heat generation and pop the fresh kernels before burning the popped kernels at the top. Many microwave cookbooks over the years have had instructions for using foil to control heat allocation as well. Keep the shapes simple and they stay predictable. – Perkins Jan 09 '24 at 03:23
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    Re: "you're looking for a technological issue to a social problem": But the only reason it's a social problem is that we don't have a technological solution. If the OP could buy a microwave that didn't have this problem, then it wouldn't be a social problem anymore. (In that case it would be no different than, say, the kids always leaving silverware in the fridge.) – ruakh Jan 09 '24 at 08:44
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    While I agree that in this particular instance there is not technological solution to the social issue, in general there are plenty of instances where a technological solution to a social issue is the by far best and easiest solution. – quarague Jan 09 '24 at 09:25
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    "Don't put metal in the microwave" is a simple, easily understood rule that anyone can follow, so it makes sense to use this rule rather than trying to explain to millions of people the much more complex reality that microwaves can and do work safely with metal in some conditions. There are microwave ovens whose entire interior surface is metal. I had a microwave with a metal turntable. The biggest problems are caused by metal that is very thin, such as foil or wire twist ties, objects that are long or oddly shaped, and things with sharp points. – barbecue Jan 09 '24 at 19:03
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Purchase a 120V 20A (or if in a different locale, 220-250V 10-15A) Key Switch (or Locking Switch) and install it (or have it installed) on the circuit for the microwave. Do not allow the children to have keys.

Locking Key Switch Locking Key switch UK/Aus format

Or, simply don't have a microwave oven at all until they become responsible.

Ecnerwal
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No, there are no microwaves that can detect if a metallic container has been placed in it. (The sparks are caused due to the presence of metal cutlery or metal in a vessel).

Please teach your kids to not use any metals in a microwave as it can cause a fire. Emphasise this strongly to them that they may burn down the house if they are not careful about this. Set aside some glass bowls and plate and teach them to use only these vessels in the microwave. Also teach them to never open the microwaves when it is running as these are harmful to us (may cause burn injuries or make us sterile).

While modern ovens have a system to stop the microwave when the microwave door is opened, I recently experienced a failure where this system wasn't activated. The microwave was still active and didn't stop and it actually damaged the touch button circuitry on the oven as these metallic parts suddenly became exposed to the microwave. Luckily I heard the crackling sounds of sparks within a few seconds and immediately switched of power, and escaped harm, and only had to spend money on repairing the microwave.

P.S: Some microwaves come with a "child lock" feature. Maybe you can consider these to ensure the young kids cannot use the microwave without adult supervision.

(If you are not sure how to talk about this with your kids, please ask for tips from https://parenting.stackexchange.com/ ).

L.Dutch
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sfxedit
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    "may make us sterile" - Source? IIRC, microwaves can only cause damage via heat. You might be thinking of ionizing radiation like X-rays or gamma rays. – wjandrea Jan 07 '24 at 21:53
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    The risk of microwaves is in heating, not ionization. Visible blue or violet light you can see (like the blue sky) is closer to causing ionization induced DNA damage than microwaves. It is when you get to ultraviolet (more "violet" (high frequency) than violet we can see) that each individual photon has enough energy to cause ionization damage to most chemicals (DNA is a chemical). Microwaves are more "red" (low frequency) than the red we can see. They are more "red" than the heat you feel from a fire, which means they can heat/burn below the sensitive layer of skin that would have warned you. – Azendale Jan 08 '24 at 00:04
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    Ok, let's accept that it is impossible to detect metal object inside the oven by the oven itself, but couldn't it be possible for a microwave oven to detect the first spark? – mrq Jan 08 '24 at 09:44
  • @wjandrea Microwaves ovens are completely safe as long as we are not exposed to it for long. I was talking about being exposed to it if the safety mechanism fails. Microwaves emit electromagnetic radiation that may decrease fertility levels. - Can Microwaves Make You Sterile? – sfxedit Jan 08 '24 at 12:03
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    @sfxedit This is true, but misleading. Heat stress reduces fertility, and microwaves heat things (see testicular function in rams, ovarian function in cows). That's possibly all there is to it. I'm pretty sure that article in your comment is blogospam, given how many times it gives somewhat-contradictory variations-on-a-theme answers in the Q&A format. – wizzwizz4 Jan 08 '24 at 14:23
  • All answers here claim that every metal in the microwave is very dangerous and harmful but it is actually often recommended to intentionally insert a spoon into a heated liquid (e.g. a cup of tea). https://physics.stackexchange.com/questions/234042/should-i-place-a-spoon-in-a-cup-of-liquid-before-heating-it-in-a-mircowave https://survivalfreedom.com/is-it-safe-to-put-a-metal-spoon-in-the-microwave/ – Vladimir F Героям слава Jan 08 '24 at 14:45
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    @sfxedit It is the same radiation that radars or mobile phones emit, just with lower intensity. It only heats stuff. Too much heat is not good for the testicles, that's why they are in a scrotum, but that's about it. Men should keep their testicles cool. – Vladimir F Героям слава Jan 08 '24 at 14:48
  • @wizzwizz4 Here's a paper on Radiation and fertility. – sfxedit Jan 08 '24 at 23:44
  • @mrq but couldn't it be possible for a microwave oven to detect the first spark? Yes. But no microwave today currently has such a feature (probably because even without sparks, parts of the microwave oven could still get damaged as metals reflect microwave). – sfxedit Jan 08 '24 at 23:52
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    @sfxedit Those studies either have low sample sizes (n≈8) or massive power (e.g. SAR 1.46 W/kg) which would induce heating, and there conspicuously aren't negative results. Here's a (more recent) systematic literature review which concludes (with limitations): “Scrotal hyperthermia and increased oxidative stress might be the key mechanisms by which EMR affects male fertility. However, these negative effects appear to be associated with the duration of mobile phone use.” I still think a regular oven is just as bad as a microwave oven. – wizzwizz4 Jan 09 '24 at 00:11
  • @wizzwizz4 I agree. Let's just err on the side of caution, I say, till we have a definitive answer. While modern microwaves are relatively safe, and I use it multiple times a day, it isn't inconvenient to keep a little distance while operating it. – sfxedit Jan 09 '24 at 00:45
  • @mrq Detecting sparks in the microwave is easy. You could sense the optical emission of the spark, or sense the RF signal generated as the spark is a non-linear process and would produce a signal at frequecies other that the driving frequency or even sense the acoustic emission with a microphone. A camera could also be used with some software (could even use some machine learing) to sense a spark and turn off the magnetron. – D Duck Jan 09 '24 at 20:11
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Sparks are created because of the sharp edges in conductors (like metals). The inside of a microwave itself is made of metal, but there are no sharp edges, therefore it is OK. You cannot avoid having sharp edges in utensils, but you can avoid them in so-called microwave-safe food bowls. Also, you can use utensils made of ceramic materials instead of metals. You can tell them apart and find in the store because the ceramic ones are not silver, but white.

Moreover, it would be better advised to increase the supervision of the children because they currently are heading a path straight to a set of Darwin awards. May be harsh to put it that way, but this is a serious hazard and you definitely need to hear it from someone with no sugarcoating. I have never heard of that causing a house fire, but these sparks create extremely high temperatures that enable the formation of many carcinogenic chemicals in the food, like polycyclic aromatic hydrocarbons (PAH). In those temperatures, even the gases in the air inside the microwave react to form harmful nitrogen oxides and ozone, inhalation of which causes acute pulmonary injuries and can be fatal. Good stuff! Or maybe not. Just be more careful please, microwave ovens are not toys.

Mad Chad
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With current technology, cooking food with steel-based silverware in a microwave oven will almost always yield sparks. Thus, changing your microwave oven to another microwave oven is currently not an option.

But what is an option is changing you silverware. From what I've researched, you can change to "silverware" made of wheat straw starch. According to the product description, such "silverware" is microwave safe (I have not tried such products myself). Here is an example of this product from the Enormous Ever-Expanding Evil Empire (no affiliation): https://www.amazon.com/Reusable-Portable-Tableware-Biodegradable-Dishwasher/dp/B09ZQFPS5D

End Anti-Semitic Hate
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  • that listing is inconsistent as to the materials (some places saying "wheat straw", others "wheat straw starch", others "wheat straw + starch + PP", and others "Polypropylene, Stainless Steel"). On that basis I don't think it's a reliable exemplar of this concept and would not trust it in my microwave – Tristan Jan 09 '24 at 16:26
  • @Tristan That seems to be a typical Amazon screw-up. I've learned to ignore everything in database fields in Amazon, as they are often wrong. Instead, go with the "About this item" information provided by the manufacturer/seller, which states "Made of natural wheat straw starch pp food grade material. Microwave and dishwasher safe." – End Anti-Semitic Hate Jan 10 '24 at 03:05
  • the only mention of stainless steel is in the database fields true, but sections entered by the seller (e.g. the title of the listing, the about this item section, and the full product description) are still inconsistent on whether the pp (presumably polypropylene) or starch are mentioned, as well as whether this is wheat straw + starch or wheat straw starch. Even discounting the mention of stainless steel, it is impossible from this listing to be confident in what this item is made from – Tristan Jan 10 '24 at 10:19
  • @Tristan Here is a blog that mentions some details if you are interested: https://ecotero.com/eco-friendly-utensils/#7-lnrkai-reusable-travel-utensil-set – End Anti-Semitic Hate Jan 10 '24 at 15:17
  • I'm not doubting that such cutlery exists, I'm saying the link is a pretty poor example given the inconsistency in description of the amterials – Tristan Jan 10 '24 at 15:19
  • @Tristan Maybe you can lend a hand and find a better link. Then you can edit the answer and provide the link you find. – End Anti-Semitic Hate Jan 10 '24 at 15:20
  • your new link would do much better! – Tristan Jan 10 '24 at 15:20
  • @Tristan I see you prefer to complain rather than contribute. Noted. – End Anti-Semitic Hate Jan 10 '24 at 15:21
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As someone always leaving silverware in microwave (despite my parents demanding not to do so) I see no foolproof method to do so. What I learned is to always make sure silverware will not touch microwave walls. But there are rare situations where food becomes burned (black) in contact with silverware.

You have to be persistent with reminders so your children will learn correct behavior.

My suggestion would be to keep microwave cover lid microwave cover lid in microwave and demand using it when heating. This mostly prevents contact of silverware with microwave walls. Having it in microwave forces everyone to do at least something with it and if kids leave it outside you can spot it easily and demand better behavior.

Piro
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    This still requires parenting (ie, you have to police the use of it). The solution is to actually parent the kiddos instead of letting them misbehave. – stanri Jan 08 '24 at 07:45
  • @stanri My suggestion does require some action from children - they have to at least put the microwave cover lid somewhere. Depending on kitchen maybe they will just put it aside but there will be evidence (I do not expect them to put it back inside). But generally I agree. As I said, I always put silverware inside despite being parent myself. – Piro Jan 08 '24 at 08:08
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    I fail to understand the emphasis of "contact of silverware with microwave walls". Metal need NOT touch microwave walls to lead to sparks (and subsequent house fire), so why emphasize this? – Matthieu M. Jan 08 '24 at 10:07
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    @MatthieuM. I think such suggestions are because liklihood for sparks / arcs increase when metal are nearer - What Happens When You Put Metal in a Microwave?. Nevertheless this isn't safe as metals can still damage the microwave oven as it reflects the microwaves. – sfxedit Jan 08 '24 at 12:13