Scary smoke and sparking in microwave--help?
November 30, 2014 8:11 PM   Subscribe

I had repeated sparks and smoking coming from the upper left side of my microwave when trying to heat a bag of popcorn and some soup (I immediately stopped it of course). However, after a thorough cleaning the problem seems to have stopped. Is it safe to assume the microwave is fine?

To be fair the microwave was pretty disgusting--food stains and even some debris (food particles only) but there was no metal or anything. I cleaned the microwave pretty thoroughly and tested it with a mug of water for 10 seconds, then 15, then 30, then 1 minute with zero issues. Can I assume I'm good to go? (Optional: If so, why did cleaning help what seemed like a severe hardware issue?). Thanks!
posted by hejrat to Home & Garden (19 answers total)
I wouldn't trust it. Buy a new one!
posted by Chocolate Pickle at 8:18 PM on November 30, 2014 [7 favorites]

No. Fire bad. Shitcan and replace.
posted by vrakatar at 8:25 PM on November 30, 2014 [15 favorites]

And absolutely unplug it in the meantime.
posted by stormyteal at 8:42 PM on November 30, 2014 [8 favorites]

Just get rid of it; spending $50 to $100 on a new microwave is worth reducing the possibility of a FIRE breaking out. Plus, imagine how stupid you would feel if your kitchen went up in flames after you ignored such a big fat warning.
posted by jessca84 at 8:57 PM on November 30, 2014 [9 favorites]

Throw that fucker out, it is waiting for you to drop your guard so it can burn down your house.
posted by Sternmeyer at 9:25 PM on November 30, 2014 [13 favorites]

Throw it out.
posted by Confess, Fletch at 9:31 PM on November 30, 2014 [1 favorite]

Micrwaves cheap. Houses and lives expensive and valuable. You do the math.

When you throw it out, make sure you mark it "fire hazard" or "does not work" or such, so no one takes it. It might be worth taking off the door and throwing that out separately.
posted by If only I had a penguin... at 9:42 PM on November 30, 2014 [6 favorites]

Fun fact; Despite what you have always been told about metal and microwaves there is metal in the base part of your microwave popcorn. It's called a susceptor.

Throw the microwave away, maybe even break the door so no one else inherits whatever is wrong, and buy a new one.
posted by vapidave at 11:54 PM on November 30, 2014 [3 favorites]

throw it out / recycle it.

Cut the cord so no one will use it without knowing its history.
posted by bottlebrushtree at 12:19 AM on December 1, 2014 [2 favorites]

Yep. Break the door off & cut the cord & separately dispose of the plate. There may have been a tiny bit of metal in the crud, like the "freshness" seal around the top of a plastic food container and you've now got rid of it. My kids microwaved a tub of nutella with the outside plastic lid on but the residual foil around the mouth of the jar inside still caused sparks and smoke and the inside showed burning. Microwaves are so cheap. Nthing don't risk it.
posted by Hillsbillie at 2:38 AM on December 1, 2014

I think the chuck-it-out brigade is probably overreacting.

The microwave radiation inside an oven can induce eddy currents and/or some fairly extreme voltage differences in conductive substances inside it, especially when you're trying to cook something without enough water content to absorb most of the microwave energy. This is why you're not supposed to put forks and spoons in there.

Eddy currents cause some pretty extreme heat dissipation inside moderately resistive conductors, and extreme voltage differences between nearby conductors causes arcing. This is why microwaving CDs is so spectacular: the thin foil layer melts and burns almost instantly due to eddy currents, and the resulting foil islands then arc across their edges.

If you allow the inside of a microwave oven to get spattered enough to be fairly described as "disgusting", some of that old food residue is eventually going to char. Charcoal is a pretty effective electrical conductor, and behaves much like the foil in a CD: it arcs and spits and sparks, and whatever is immediately next to it gets really hot and smoky really quickly.

I have had housemates skilled in the art of gunking up the inside of the shared microwave at unbelievable speed, so I have seen this happen fairly regularly. The most common place for burnt-on gunk deposits to become spectacular ignition sources is the surface of the little nonmetallic plate that usually covers the magnetron's waveguide outlet into the oven chamber.

If you've got all the gunk off the inside of yours and it's now heating water as fast as it did before it put on its little indoor fireworks display and it's no longer belching smoke: it's probably fine.
posted by flabdablet at 4:19 AM on December 1, 2014 [11 favorites]

Microwaves are about $19 new.

Throw it away with extreme prejudice.
posted by Ruthless Bunny at 6:21 AM on December 1, 2014

I'd keep it. If you do throw it away, keep the plate, you might be able to sell it. When I broke the plate for my microwave, I found out it would be $40 to buy a replacement!
posted by catatethebird at 7:02 AM on December 1, 2014

Seconding flabdablet. A little stray bit of char or metal will do exactly what you found.

Just monitor the microwave when you're using it from now on (i.e. don't turn it on and walk away, stick around and keep an eye on it).
posted by JoeZydeco at 7:14 AM on December 1, 2014 [1 favorite]

This would make me nervous too and with all the microwaves out there you can get a new one (along with piece of mind) for a good price. That being said, I work at a large apartment complex and our maintenance crew has told me that sparks in the microwaves a lot of times just means that they need to be cleaned (VS. being replaced, which they'd rather not do so take that with a grain of salt), especially the wheels underneath the plate I think. I'd probably just get a new one but YMMV.
posted by Shadow Boxer at 8:54 AM on December 1, 2014

which they'd rather not do

All the maintenance folks I know are heavily biased against wasting fully functional equipment for essentially superstitious reasons.
posted by flabdablet at 10:05 AM on December 1, 2014

Sounds like there's an exposed piece of metal there, and you can't find it.

A new microwave costs less than $100. Is your house worth more than $100? Is your life worth more than $100? Replace the microwave with a new one.
posted by tckma at 11:11 AM on December 1, 2014

I had a microwave do this when I wasn't home, the wife got the fireworks. Being a lazy shiiite at the time, I didn't replace it. It ended up lasting about 5 more years, or, 3 years longer than the marriage lasted.
posted by rudd135 at 4:26 PM on December 1, 2014

Best answer: OK, I'm coming back to this due to a MeTa thread. I typed up an answer yesterday but a posting glitch ate it and I didn't have the time to retype. I'm not going to say either side is wrong on this but here's what I think:

The OP was unclear on two things that I think are salient to an answer: 1. Were there any "failing electrical device smells" at the time of the arcing? e.g. fried electronics or melting plastic? If Yes then I'd lean (heavily) toward disposal. If No then 2. Was there any metal in the food/packaging being heated (see the susceptor comment above) or traces in the cleaned-out gunk? If Yes then I'd lean toward keeping it. If No then ?

And everybody should have an fire extinguisher in their kitchen. I was going to say an ABC one, but TIL there is a "K" designation too (I guess if you don't have big pot lids?).
posted by achrise at 1:28 PM on December 2, 2014

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