Sorry, but that's an immediate PAT test failure because of microwave
leakage. You need to render it unusable (cut the mains cord off right
up against where it enters the case) and dispose of it. Repairing it
safely and correctly would be much more expensive than a replacement.
[email address is not usable -- followup in the newsgroup]
On 16 Jun 2007 16:51:24 GMT, firstname.lastname@example.org (Andrew
Okay, okay, hofficer! I'll come clean! Look, no guns! No, that's just
a table leg! I was trying to render the microwave unusable. ID card?
DNA sample? What else do you need? Oh, my fingerprints. Right-o.
replying to MM, John A Knight wrote:
I know this is a very dated post, however I'd like to post a more constructive
Q: how to "*/_repair_/*" a hole in a microwave oven?
The internet is a network of information, unfortunately we did not find it here,
I will continue my research into this topic, I will update my reply when I have
a tried and tested repair method(s), ***for now, for all of us who share this
problem I recommend following the warning signs on the kitchen appliance (do not
place mental or foods that increase in pressure has they cook ect.) if the hole
in the microwave oven is bigger then 2 inches for your safety I recommend
*/_not_/* using the microwave oven, if the hole is 2 inches or smaller I
recommend keeping it isolated (away from anything that's a fire hazard), putting
it in a clay or dish tray and leaving the kitchen while your meal is prepared.***
This is just my opinion and I do not wish to impose it on to anyone, it's easy
to through money at problem rather then maintain it, I believe there's no harm
in trying to be self-sufficient and acquire a new skill.
I hope this helps everyone a bit.
Thank you for the thread MM.
On Thu, 19 May 2016 10:04:14 -0700 (PDT), email@example.com wrote:
Clearly the OP needed to buy a new microwave, but from an RF
perspective the information on that scienceabc.com page is actually
I thought it was complete bollocks too; it treats microwaves as if
they're tennis balls, but I'm no microwave expert. If it's not
bollocks, and if microwaves can't leak out of a hole smaller than 12
cm. why all the fuss in the past about microwaves leaking around
ill-fitting doors, and why the need for a fine mesh across the window
in the door? If the article is OK, you barely need to shut the door,
let alone worry about leaks around the edge, and wide-mesh netting
would do in the window allowing a much better view of the contents.
What am I not understanding?
This issue is nothing specifically to do with microwaves. It relates to
*all* sorts of waves and their behaviour. Look up diffraction. I'd do
it meself, but SWMBO has just announced that the scoff is ready.
Anyone who slaps a 'this page is best viewed with Browser X' label on
a Web page appears to be yearning for the bad old days, before the Web,
OK. I know a little about diffraction (A-level physics circa 1962 but
not a lot since), but I looked it up on Wiki anyway. It says, amongst
other things, that diffraction is most pronounced when the width of
the slit or aperture matches the wavelength of the radiation, which is
the situation in this case. But the aperture doesn't block the
radiation completely. You just get a pattern beyond the aperture of
alternating destructive and constructive interference, either side of
the main beam. I wouldn't want my kidneys positioned either in the
main beam or at a point of constructive interference, while watching
my supper cooking. And it doesn't answer my point about gaps around
the door, or the screen mesh across the window.
The issue us not diffraction, but reflection.
You don't need a perfect surface to reflect.
Its the same principle as using a yagi array or similar. The presence of
the metal bits affects propagation around a far greater volume than they
physically occupy, because a field is induced in the nearby areas.
"When one man dies it's a tragedy. When thousands die it's statistics."
If considerable energy can diffract or otherwise pass through wide
mesh netting, and I don't doubt it for a minute, how can a bloody
great hole 12cm across not be a major hazard, as the article linked to
at the top of this thread said wasn't? (hope I've not got double
negatives there, but YSWIM!)
well 2GHZ is around 3.75cm for a quarter wave..
so its of the order of a wavelength anyway.
I am fairly sure that diffraction is a bit of a red herring though.
Its one of those lectures I probably didnt pay much attention to, but I
think its a matter of reflection.
You can build a radar reflector adequately out of chicken wire..
"It is an established fact to 97% confidence limits that left wing
conspirators see right wing conspiracies everywhere"
I found this:
I guess the implication is that although the wavelength is a few cm,
the mesh has to have small holes to sufficiently reduce the radiation
that would diffract through the holes.
"... you must remember that if you're trying to propagate a creed of
poverty, gentleness and tolerance, you need a very rich, powerful,
As anyone who has ever tried to make an RF-tight screening box will
know, the problem of totally confining the RF energy bouncing around the
innards of such an enclosure so as to eliminate unwanted interference to
other kit or other modules within the apparatus is not quite so simple to
solve as it may appear to the uninitiated (I had quite a laugh at the EMC
'measures' being introduced in the construction of personal desktop
computer cases nearly two decades ago).
Whilst a screening mesh with a hole (or a few holes) less than a
wavelength in diameter makes a reasonably effective screen, it's not
perfect, merely 'perfect enough as makes no difference' in practice.
Such a screen won't totally stop such radiation passing through, it
merely attenuates it to a much lower level (maybe 40 to 60db per sub-
wavelength hole?). This is usually more than enough when the waves only
get one chance to pass through the screening mesh. However, in the case
of the cooking cavity, they'll get hundreds, if not thousands of attempts
at leaking out as they bounce around the low loss cavity.
The food will absorb most of this energy... eventually but there will be
eigentone pathways not obstructed by the food where the levels of
radiation will be magnified hundreds to thousands of times the average
level in the cavity. Quarter wavelength diameter holes in the viewing
screen mesh won't offer sufficient attenuation, halving the diameter of
these holes will require a quadrupling of said holes which counters the
improvement in screening to some extent, hence the *very* small size
compared to the wavelength involved to sufficiently attenuate radiation
leakage to below a level deemed to be acceptably safe.
The smaller the holes, the better and the most likely reason for their
extremely small size is probably more to do with the lowest size possible
without offering too much obstruction to viewing the contents rather than
a maximum allowable size to contain the microwave leakage to an
The issue of holes in Microwaves does beg the question how did the hole get
there in the first place of course. I stand by my method. I assume one can
still buy those microwave leak detectors. The most likely place for the
microwaves to leak is at the door bottom which tends to rust away.
Short term, ie ten seconds or less exposure is not going to do you much harm
as you measure the leakage.
Remember its a party trick in radar labs to heat up your sandwhiches using
the open end of a waveguide when it is connected to a magnetron. :-)
This newsgroup posting comes to you directly from...
Fuck off homeownershub.com
Future generations will wonder in bemused amazement that the early
twenty-first century’s developed world went into hysterical panic over a
globally average temperature increase of a few tenths of a degree, and,
on the basis of gross exaggerations of highly uncertain computer
projections combined into implausible chains of inference, proceeded to
contemplate a rollback of the industrial age.
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