About metal in microwave ovens

[jw]

We are not supposed to put metal in microwave ovens, and I know all too well what happens if someone does do it. It's a pretty wild show of sparks if metal is put inside.

Anyhow, I'm puzzled about something. Metal put inside when the oven is on, will blow sparks, but the bottom of my microwave is made out of metal. It's a type of steel, which I know because where the glass pan rotates, it's worn off the paint and is rusting. Anyhow, how come that metal dont spark?

While I'm here, to repair that rust on the bottom, can I use spray paint? Do I need a special paint such as a high-temperature paint?

Thanks

[Ed Pawlowski]

It won't spark because it does not have another piece of metal to jump an arc to. Modern microwaves can have some metal in them. Flat tray is OK, but a spoon sticking out of a cup is like a lightening rod. Small pieces of foil used to cover certain areas is OK also. Often used for the corner of a tray of brownies or the tips of a chicken leg. OTOH, I'd not MW a chicken anyway.

I would thing you'd want some type of epoxy paint, but I've never tried it.

[Frank]

We had same problem and wife was concerned. We had constantly used appliance touch up paint but corroded area was on ring where tray rotated and would wear away in a short time. I was about to go to the hardware store to look for a special, durable paint when wife went out and bought a new oven. For less than $100, microwaves are like toasters to be discarded readily.

[Colbyt]

Ed, I suspect there is slightly more to it than that.

While working at a single house over the winter I stocked up on some MW food supplies. One of the soup brands is a composite container with a metal crimped top and pull ring. 90% of the top is removed when opened but there is a metal ring remaining. They heat just fine with no arcing. I have not taken the time to research why.

Colbyt

[Art Todesco]

A lot really depends on relative amount of metal compared to the amount of food. If the food absorbs the microwaves and thus heats the food, there will be little to reflect by a small piece of metal.

[LSMFT]

My wood fired microwave doesn't spark.

[Tony Hwang]

Hmmm, MW is focused EM beam.

[Steve B]

I have a convection microwave. I don't understand that there is a metal turntable and rack, and there's no arcing there.

Steve

Heart surgery pending?

Heart Surgery Survival Guide

[Steve B]

I tell you what, you can definitely set a bag of popcorn on fire in a microwave. I hadn't cooked any for a long time, and put it for a minute or two longer than it was supposed to go. Soon, my dog was barking like crazy. I came in, and the mw was smoking like hell. I opened the door, and WHOOMPH, the air hit it, and the flames came. I grabbed a couple of oven mitts and took the glass tray and burning bag out the door. The smoke was so thick you couldn't see anything from waist up. The smoke detectors were all going off. I opened the doors, and the neighbors came, but no one called FD.

"Stuff" can catch fire in a microwave very easily, and if it doesn't, just leave it in there for a few more minutes. This was a 1400w. microwave.

Steve

Heart surgery pending?

Heart Surgery Survival Guide

[Roy]

=3D=3D I put a refrigerated peanut butter jar in the MW for about 20 seconds to warm and soften it and didn't notice a small bit of aluminum foil around the top edge. I had one very nice "torch" for a while. I learned my lesson on that one. =3D=3D

[Twayne]

The real reason is the cabinet is grounded and the tube also uses gnd for a reference, so there's no jumping inside it. What you put into it though, isn't grounded.

I'd use an epoxy myself but I don't know that's the right answer; just what I'd try first.

If you want a pretty show, put a CD or DVD into a uWave. Very pretty, lots of colors. Doesn't hurt the uWave either. I have an old one I've been trying to break and it just keeps on ticking!

Twayne`

[DerbyDad03]

I've tried to soften Peanut Butter in a MW and the tiny bits of foil spark like crazy.

On the other hand, I can soften frozen juice mixes in those cardboard containers with the metal ring around the bottom. In fact, it was the manual for my Sharp MW that suggested that.

The same manual also says that I can use strips of foil to cover the edges of chicken cutlets, etc. when defrosting.

So the question is this:

Why do microwaves hate Peanut Butter?

[Steve B]

"Roy" wrote

I put a refrigerated peanut butter jar in the MW for about 20 seconds to warm and soften it and didn't notice a small bit of aluminum foil around the top edge. I had one very nice "torch" for a while. I learned my lesson on that one.

Me, too. I thought, wtf could go wrong with peanut butter. I missed a couple of bits of foil from the seal. It's amazing what a small amount of foil will do, and the sound and lighting effects are pretty amazing, too.

A CD for three seconds is pretty cool, too. Make sure it's not a good one.

Steve

Heart surgery pending?

Heart Surgery Survival Guide

[robb]

I've seen many steel/metal/chromed/brushed nickel racks/shelves in=20 microwaves. I regularly leave forks and spoons in the food while heating and have=20 had no sparks or explosions

however, if you don't mind some wear and tear on the microwave oven=20 there are many objects that cause some pretty cool light/electric=20 shows google cool things to put in microwave will probably find the site=20 that has video and ideas.

I've done the cut grapes and CD... those were fun

This site (as do many others) explain the metal in microwave issue.

[aemeijers]

I don't have a merry-go-round in my micro (I think it has a spinner in the output waveguide), but it does have a metal grate to set the food on. There is a Z-shaped jog in the thick outer bars on the ends, and I always wondered if that was something added to eliminate sparking, somehow.

-- aem sends...

[zek]

Epoxy paint seems ok. What not many mention is metal and wavelengths. If you don't know antennas and wave guides, the physical size of the piece of metal is what's most important. Like the seal around the door is 1/4 wavelength so the 2.4 ghz radiation stays inside the container.

The 1000 watts inside is what we used to send to the moon to the astronauts, but with a big directive dish. The frequency to the moon was also very close to that 2.4 GHz was

2.275 GHz.

I used to like to see metal foil ho ho's arc in the microwave.

I built my first microwave, Heathkit, in1971. My buddie had one Amana in, 1967.

The heath kit had a poor design on the front door. Too much leakage!!

Greg

[Pete C.]

Urban legend mostly. You most certainly can use metal in a microwave with no issues at all, as long as you understand a few guidelines.

- No thin metal bits such as metallic decoration on plates, or wire twist ties

- No metal with sharp points (concentrates microwave energy)

- No metal too close to the edges of the microwave

- Enough food mass to properly absorb the microwaves

Thus, metal bowls with rolled edges that are small enough to not get within a couple inches of the edges of the microwave are fine to use. Spoons with rounded handles in cups or bowls that are again, not too close to the edges are fine.

Some microwave ovens come with metal racks for two level cooking, some with metal temperature probes, etc. Microwave instruction manuals have long instructed to use aluminum foil to shield thin parts of the food to prevent overcooking.

[DerbyDad03]

If no thin metals bit are allowed, why can I use small strips of aluminum foil to cover the ends of meats while defrosting?

[Don Klipstein]

I have tried breaking eggs open and dumping them into a microwaveable container to cook them with a microwave.

Results: Apparently, the stuff cooks OK until interior of a portion that solidified becomes superheated. Visually and audibly: BOOM! and mess, though not as loudly and forcefully as I imagine could be the case with an unbroken egg.

[JoseGomez]

Want to see a real explosion, put your testicles in a microwave. KABOOOOOMMMMMMM.....