Fire in Microwave

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Hi,
Make, model#, approx age of the microwave?
Most newer ( 10 years and under ) microwaves will boil cold water in a coffee mug in approx 3 minutes....test and if the microwave boils the mug of water in that time or longer, it is not cooking faster as she thought it was.
jeff. Appliance Repair Aid http://www.applianceaid.com /
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jeff wrote:

3 minutes is too long. Our 1000W microwave boils a full cup of cold water in about 1 min 55sec. Takes about 2-1/2 minutes in the small unit in our travel trailer.
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warm
until the

than
things in

of
Three minutes is likely long enough in some ovens for a cup of coffee to explode in your face from superheat if it fails to actually boil prior to taking it out....
--

SVL





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Standard microwave check is 3 minutes for water to be boiled! Longer is often a weak microwave. Shorter can be one of the newer high output microwaves ( no make or model# posted by OP ) but the standard time still is *approx* 3 minutes for most microwaves. http://www.microwavecookingforone.com/Charts/Wattage.html
jeff Applaince Repair Aid http://www.applianceaid.com /
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to
But you seem to have entirely missed my point..........
Under certain conditions, microwaved water and other substances can and sometimes will become signifcantly hotter than their own usual boiling point, and without ever actually coming to a boil.
http://www.llnl.gov/es_and_h/lessons/MicrowaveHeating.html
At this point, it can be quite dangerous, and a slight shock or or other mixing of gaseous subtances, particularily air, into it will initiate a sudden eruption of the liquid into a violent boil, spewing hot liquid and vapor outside of the container and possibly burning an unsuspecting individual.
This condition is known as superheating, and is the reason I wouldnt recommend anyone should continue with application of microwave energy into a container of liquid just because it hasnt yet come to a "boil".
=== While on the thermodynamic properties of water--heres an interesting site perhaps for some, click the various links to learn about the different types of ice and their physical properties as to pressure, density, temperature and atomic structure :
http://www.lsbu.ac.uk/water/phase.html
"Ice-seven has known triple points with ice-six and ice-eight (5C, 2.1 GPa), ice-eight and ice-ten (100 K, 62 GPa) and liquid water and ice-six (81.6C, 2.2 GPa). Interestingly, at high pressures (~ 2.3 GPa), liquid water can be made to freeze at over 100C (to give the more dense ice-seven). The dielectric constant of ice-seven is about 150."
=== Cheers,
--

SVL









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jeff wrote:

Mine does in it 99 seconds. Not a good test, unless she has a timed test for hers prior to the event.
--
Joseph E. Meehan

26 + 6 = 1 It's Irish Math
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I just read more than I want to know about microwaves at the stupid microwave tricks site a poster provided. The reading made me understand that you can superheat water in a microwave without it EVER boiling. So, I believe your 99 second time trial may vary with another cup of different material or shape.
Steve
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A standard 6 to 8 ounce mug of water should boil in about 2 minutes in a 1400 Watt microwave oven, if it is working properly. Take care to not super-heat the water. At this point it can erupt, thus causing sever burns. At over 2 minutes, this quantity of water may be super-heated.
In some makes of microwave ovens, the service manual gives a test procedure where the tech would put in a mug of a particular quantity of water for a particular cooking time, in to the microwave oven at a specific position. After the set amount of cooking time has taken place, he then removes the mug of water, and must take a temperature reading. The different models may have different temperatures, therefore this test is model critical. This is a fairly good way to test the performance from the reference of the unit under test.
--

Jerry G.
=====


"jeff" < snipped-for-privacy@hotmail.com> wrote in message
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[snipped]

Hello Jeff,
It is a 700 watt Sharp Carousel II. It was built in 1989. She bought it new. I don't know the model number. Next time I am visiting I will look it up.
Regards, Newby
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Newby wrote:

At 15 years, it may be time to retire it. I suspect it is ok, but the event may have done some damage to the oven. Today's models are cheap, more powerful, more features (some of which are acturally useful) and smaller on the outside. I suggest it may be time for a new one.
--
Joseph E. Meehan

26 + 6 = 1 It's Irish Math
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<snip>
And as a plus, they may even last 5 years.
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Ian Stirling wrote:

Acturally they seem to last as long or longer and are less expensive.
--
Joseph E. Meehan

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Ian Stirling wrote:

My huge Litton microwave lasted 25 years believe it or not. I'll be interested to see how long this Kenmore lasts, which is 2 yrs. old now. BTW, it's popcorn button [timer] works as advertised, but I never leave the room, anyway. And it boils water in a plastic cup I use for that purpose, in a minute and a half. Sixty seconds and simmering is fine for me. bj
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Hi,
A copy.....
Approx 2:30min for a 700 watt micro.....from http://www.microwavecookingforone.com/Charts/Wattage.html Instructions: Find the amount of time it takes to boil one cup of water in your microwave oven in the first column, "Water Boils." The number next to it under "Oven Wattage" is a close approximation of what wattage oven you have.
Maybe your friend is "on" to something....burn some fast food burgers in your microwave and it becomes faster ;)
jeff. Appliance Repair Aid http://www.applianceaid.com /
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I don't know how the oven could cook faster, unless something now prevents its power level from being lowered as much or if the moisture sensor became coated with soot and isn't as sensitive (would matter only if programmed timing modes alter the power setting). The only way to be sure is by comparing it with an identical oven that's been used about the same amount (microwave tubes weaken as they age) by heating up measured amounts of water for 60 seconds and comparing each temperature rise (FYI, power = 70 x (temp rise) if you measure in Celcius and use 1 litre; power = 37 x (temp rise) if you use 1 quart and Fahrenheit). Don't touch the insides of a microwave oven unless you know how to work on high voltage devices, and even then you want to avoid touching the microwave portion (big transformer, big capacitor, magnatron) itself because of the extremely high voltage (over 1,000V), not to mention the very strong microwaves. Stick with the lower voltage areas only, like changing lightbulbs or touch pads, but even they operate at enough voltage to kill you. Microwave ovens are so cheap that the only ones worth having repaired any more are the overhead units and the combination microwave/convection ovens. But if a microwave oven has any damage at all to its door or cavity (i.e., smashed or dropped), cut off its power cord and toss it.
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N > A friend put a couple of 'fast food' hamburgers in her microwave to warm N > them but forgot they were wrapped in aluminum foil. When she saw the N > ensuing fire she turned off the microwave and kept the door closed until th
N > brief fire burned itself out.
Correct procedure for the fire.
N > The microwave seems to operate normally but she swears it cooks hotter than N > before the fire. In other words it doesn't take as long to heat things in N > the microwave. Does this make sense to anyone? If it does, what kind of N > repair would be needed to make it right again.
I also doubt it is cooking faster; if anything seems like it would cool slower bcause of the soot coating from the fire.
As for cleaning up after the fire, soap and water should do the trick; nothing abrasive.
- barry.martinATthesafebbs.zeppole.com
* Why is "ABBREVIATION" such a long word?
--
RoseReader 2.52 P003186
The Safe BBS Bettendorf, IA 563-359-1971
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Somebody wrote:

Repair? I'm getting ready to torch some foil covered burgers in mine to see if I can get it to do the same thing. LOL
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Most microwave ovens have a "stirrer fan" at the top of the oven cavity (often hidden by some kind of cover). This stirrer reflects the microwaves around the oven to produce more even cooking.
If something happen to that fan and it is not longer turning, the microwaves may be getting concentrated in certain areas and heating food placed in those areas more than food in the other areas of the cavity.
It is unlikely to be heating more *overall*, but it could be heating more in certain areas and less in others.
JMO
Dan O. - Appliance411.com http://ng.Appliance411.com/?ref411=Sharp+microwave
=~~~~~~
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