Placing objects on top of a microwave oven

Hi,

I have a question about microwave ovens which probably sounds a bit
silly, but here goes...

Prior to purchasing a small microwave from an online store, I needed
to check whether it had vents on top of the unit, as in my small
kitchen it would be on a benchtop and I wanted to use this space for
resting light objects. I've never actually seen vents on the top of
any microwave, but the manual was non-specific and suggested there may
be, so I thought I'd better check. The manufacturer's respresentative,
who'd just returned from speaking to technical support to get an
answer to my question about the vent location (they're on the side),
very strongly warned against placing objects on top. Even small
objects, I asked, like cooking utensils? "No, no, no way! It might
blow up".

Now, I understand these companies have liability issues to worry about
and will warn against pretty much everything. Common sense tells me
that placing a teatowel on the top surface (in such a way that it
doesn't over the edges and cover vents) and resting light objects like
clean cooking utensils on it should not be a problem, but I'm not up
to speed on electronics so perhaps there's a technical issue I'm not
considering. Is any technical reason why I should not place light
objects on top of a microwave?

Ed

 

No. It's a sheet metal box, for heaven's sakes. ;-)

Don't block the vents, or the thermal cutout will make it
stop cooking till it cools, but as far as microwaves, it's
an inert box. Grounded, BTW, so you can even put static-
sensitive utensils on top. ;-)

Bon Appetit!
Rich

 

----------
No, he's as uneducated as you sre, he's just covering his ass.
Remember him the next time your ignorsnce leads you to cover
YOUR ass.

-Steve

 

Thanks, Rich. Sounded like it was actually worth asking about (at risk
of looking like an idiot) after I got off the phone with them, but in
retrospect it does sound rather silly

Ed

 

Ed,

Vent openings should - off course - never been covered. But a microwave that
blows things that are placed on top of it is a very dangerous appliance. It
sure does not fulfil the safety regulations and is not allowed to be sold in
most countries. So I think that representative did not know where he's
talking about like most salesmen often do. The only accident I ever met was
fatal for some pottery placed on top of the microwave. Due to the vibration
caused by the turntable the pottery walked to the edge and beyond...

BTW. Microwaves *never* should leak out of the oven. As fat and grease tend
to conduct microwaves, you have to keep your oven clean. Especially the door
and posts.

petrus bitbyter

 

WARNING WARNING WARNING!

The TOP of your microwave oven could be dangerous, but not for the
reason anyone thinks.

In some ovens (like mine!), the light bulb that illuminates the
inside of the oven is very close to the metal top. In normal
operation this causes little problem. However, if you leave
the oven door open for many hours, the light stays on, and
the metal top becomes extremely hot. Plastic bags fuse to the
paint. Candles turn into pools of liquid wax. I doubt it
could start a fire, but it certainly could destroy a CDROM left
up there.

 

Have you seen the CD inside the oven? Now THAT destroys it.
gg

 

Can someone explain why we worry about door seals on microwaves leaking,
when the door has a metal grill that I can see through!

Peter

 

Because the holes are smaller than the 1/4 wave length of the frequency
in use, so for all intents at the 2.5GHz or so the oven is using the
grill is a solid piece of metal.

 

You might have noticed William J. Beaty's reply. I completely forgot
about the light bulb, so I was wrong. If the light stays on for a
long time, the top of the oven will get hot.

Cheers!
RIch

 

I wonder what size of hole would cause problems? In my old oven,
the 0.25" hole I drilled in the top had no measureable leakage. At the
same time, there were a few mW/cm^2 at one corner of the door, and the
door was NOT damaged or even dirty.


PS

Drill a hole in your oven wall! It lets you reach in with a plastic
stick and poke at sizzling sample-objects. Or stick an NE2 bulb in
the end of a soda straw and explore the 3D hotspot pattern.

 

Microwaves are by no means - my specialty, so my assumption here could be
wrong.... But I'm wondering.... the hole on "top" of the microwave maybe
being "above" the main oven components - was still "shielded" from the
"active" parts? Where as the door was inline with the deflected microwaves?
Just a guess.

As to placing things on top of the oven, I do and have been for a while. No
big deal as most of my cooking time is less than 10 minutes. Now, if it were
to be say an hour, I'd probably move the stuff as I have noticed that the
oven "starts" to get a little warm at the 10 minute mark. And no - the vents
are not blocked. They're out to the sides and rear. There is sufficient
space on the sides and rear to allow for it.

 

Don't drill a hole in your oven.

No, actually, it is because up to a certain size, the microwaves don't
even realize that there's a hole there. It's too small for them to
get through, just like the holes in the door grille.

This is also why ants don't cook. ;-)

Cheers!
Rich