NUKING a Grape in the microwave

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MrAl
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Post by MrAl » Wed Feb 07, 2007 6:36 am

Hi,

I actually had my water in the microwave super heat one time.

I used a glass pot with a single handle and a glass lid.
The water had been heating for some time in the mic, then i
opened the top and dropped in a half tablespoon of salt into
the water. The water gushed up very violently and surprised the
heck out of me because this was before rumors of super heated
water started getting around.
I was lucky though as the pot was still in the oven and although
it was a violent expulsion of water i didnt get any on me or even
on my hand which was in the oven.
Because of this i warn people about using glass cookware in the
microwave. The pots i use now are very different because they
are not as smooth, and the smoother the surface the more
likely the water could become super heated.
LEDs vs Bulbs, LEDs are winning.

High4Volts
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Post by High4Volts » Wed Feb 14, 2007 12:35 am

Anyone ever tried to put an egg in there? Me and a buddy did that once at his house. Blew the door open and egg all over the kitchen cabinets on the other side of the kitchen.

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dacflyer
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Post by dacflyer » Wed Feb 14, 2007 3:44 am

ya i did that..but i poked a hole in both ends 1st thinking that would releif any pressure.....the darn egg still turned into a grenade...lol but didn't blow the door open or off..:P

live and learn !

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GoingFastTurningLeft
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Post by GoingFastTurningLeft » Wed Feb 14, 2007 9:53 am

I remember seeing the flourescent bulb thing on Mr Wizard.

And that Brainiac show is pretty good... Its a couple years old though, an import from the UK. Grabbed a whole bunch with bit torrent a while back.

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haklesup
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Post by haklesup » Wed Feb 14, 2007 12:58 pm

Those Sears guys finally finished with my Microwave. They pronounced it unrepairable and left it in a pile at my house. When we got it open the magnitron was toast as expected. (it emitted a loud arcing noise when operated). The arcing had punctured a hole in the sheetmetal waveguide allowing for escape of microwave radiation. Since the waveguide was an intregal part of the unibody chassis, it is not replacable.

Take a look:
Image

Image

Image

I can't really tell if the dome shaped welt concurrent with the burning was formed by the arcing or if it was part of the original form. I think it was once flat but now is raised about 1/3 of an inch for the area with the whitish burn ash on it and where the paint came off.

Well, I bought it at an outlet store, who refunded my money yesterday. I still have the bad oven and they said bring it to a store or nothing will happen. Hmm, looks like spare parts to me now.

I have a new magnitron also (1000W), I wonder if it is safe to close up the hole with an arc welder and put it back together. Its a shame to junk it, it never even boiled its first cup of water.

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Chris Smith
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Post by Chris Smith » Wed Feb 14, 2007 2:54 pm

Talk about feed back?

A magneton is a great weapon for those who shouldn’t know its really there,... but run any way.

Sounds like a bunch from DC, just jamb the door open and aim it and watch them run like worms!

Doesn’t even need to run, other than the light!

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jwax
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Post by jwax » Wed Feb 14, 2007 3:52 pm

The HV supply makes a nice Jacob's ladder! :grin:

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haklesup
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Post by haklesup » Wed Feb 14, 2007 4:22 pm

I do have a theory. I noted that the magnitron was magnetic. If any steel debris were left in the oven or waveguide, it probably would have found its way to the magnitron output (during shipping) and just stuck there waiting to cause a short that ultimately caused physical damage that led to the continuous arcing failure. Since any metallic debris would have been vaporized, the evidence of the root cause of failure is likely gone now.

I bet I could use the control panel to operate my steam room. I can tell people I converted it into a microwave sauna and watch their faces as fear sets in.

Other than the xfmr, cap, and controller, there's nothing left but some fans, lamps and switches. Ultimately the most useable of the parts.

I haven't decided yet but knowing me it will probably get returned, yet I still wonder.

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Chris Smith
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Post by Chris Smith » Wed Feb 14, 2007 6:18 pm

All energy in any magneton is = to voltage.

MW = Voltage

Any feed back circuit must be resilient to this voltage.

The shellac on a winding is only rated to 600 volts, the magneton at full power is 2.4 thousand volts, assuming its not feeding back into the magneton.

Any mirror of this voltage will result in a feed back to the insulation, cooking, arcing and finally a burn through to the whole system.

Its not rocket science.

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dacflyer
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Post by dacflyer » Wed Feb 14, 2007 8:41 pm

another thing also..since that wave guide is burnt..its likely the inside is toast as well,,the carbon inside it, will be the 1st thing that the mag will look for as soon as its powered up...they love to find carbon !

as for that dimple thats there now,, thats made like that..its head room for the mag antenna.

i'd scrap it..unless you find another microwave like it with a bad mag or control board,,

i have seen murned mica shields on microwaves, but never one that burnt thru the waveguide,, WOW...good thing the cover was on the microwave..secondary shielding... if its plugged into a good ground.

be safe,,scrap it !

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