OT: More power from Microwave oven - Power to melt metal?

Yes, it is an ordinary albeit big microwave oven.

The trick is that high-temperature foam ceramic and/or fiberglass-like insulation is transparent to microwave energy, while trapping the heat, so the temperature just keeps increasing.

Which brings us to a problem: How do you tell how hot it is?

Not really. Or rather, not enough to be worth the trouble. The magnetron is what it is. Likewise the power supply, and these two are the main cost drivers. Everything in such an oven is exactly as big as it needs to be, and not one iota bigger. It's a very cost-sensitive market, and pennies count.

And this really is one of those if-you-have-to-ask questions: If you don't already know enough about how a microwave oven works to answer the above question, the oven's 2,500-volt 1000-watt power supply is likely to cut your education short.

I've seen some postings on other groups/websites on this, but their consensus was that while it was a cool trick, it really wasn't worth the trouble for real use. For one thing, 1000 watts isn't all that much, and resistance heating is far simpler and cheaper.

Joe Gwinn

I've seen a web article about doing this in a standard microwave. the trick is you need something electrically conductive and about the right size (to couple to the RF wavelength) to absorb the microwave energy. Some ores will absorb enough even when a powder, otherwise you may need to "dope" the ore/raw material with a ring of steel or metal compatible with what you are trying to melt, or some carbon or graphite. Once the metal starts to melt, it will become a conductive single mass and take over the job. Somebody did gold assays with multiple crucibles of ore samples, but he had to add a conductive material to the mix to get it started.

I would NOT recommend doing this in an expensive kitchen appliance, even if you live alone. If there's a "woman in the house", don't even THINK about it! You can likely find an older, big microwave with a trashed electronic timer/control. There should be one big and one small relay or Triac switch. The big one goes to the main power transformer, the small one runs the light and cooling blower. You can bypass these and just put in a big power switch, or clock-type timer. Note that when the electronics board goes belly-up, it will likely cause the "suicide" fuses to pop. By law, microwaves and a few other appliances like clothes washers need suicide circuits to blow "no user servicable parts inside" fuses when a malfunction compromises the safety system.

You just don't want molten steel getting loose in a $900 kitchen appliance. And, if you are melting steel or gold in crucibles, spills, splashes and failed crucibles will eventually happen.

Finally, you can melt, MAYBE, a pound of steel in a microwave, if you are REALLY patient. That could take a half hour, and inches of refractory around the crucible. If you want to melt an ounce of gold or silver, however, it should work quite well.

Jon

Regards,

Boris Mohar

Got Knock? - see: Viatrack Printed Circuit Designs (among other things)

"Bart D. Hull" wrote in news:45bce949$0$93354 $ snipped-for-privacy@news.getnet.net:

Here's a related story.

You sure have expensive taste in kitchen appliances :-).

I could get a decent domestic microwave here for under £100.

Try putting steel wool in an old microwave if you want some fun.

Best wishes,

Chris

$49USD at Walmart

"Deep in her heart, every moslem woman yearns to show us her t*ts" John Griffin

Not me! We still use an Amana microwave we got from my mother in law. It is from the early 1970's. I've made a few repairs to it, but the tube still works!

The original post said "700 watt GE microwave/stove/conventional oven" so I'm asuming this is an all-in-one contraption. Those are expensive.

Or light bulbs, ceramics with gold leaf trim, turkey bags with wire ties, or my favorite -- a friend tried to dry out wet holiday fireworks after a surprise storm. You needen't even ask, only a drunk person could possibly think up such a plan! Results were totally predictable, the friend had to carry the exploding oven out the door to the backyard while all hell was going off inside. (I'm having trouble seeing the screen due to the tears in my eyes right now!) Just too bad I wasn't there, just hearing it retold was enough. I have seen the microwave, however. It actually didn't look as bad as I would have expected!

Jon

One of those induction stovetops might be better suited for heating metal.

Steamed M-80s all around! ;-)

And normally replaced with a conventional gas or electric range and a "Vent Hood" style Microwave oven, and with a LOT of change left over.

We have condo complexes who call as the old All-In-One MWO ranges break in the various units, and they need a new receptacle in the upper cabinet.

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