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A Foundry in Every Kitchen
WolfWithoutAClause writes "Bored with making the same old food or
plasma in your microwave? David Reid sounds like he is. He's using his domestic microwave oven to melt iron, silver and bronze! Over 900C! I don't know about you, but I'm going to be checking the temperature of my pizza rather more carefully in future..."
Try putting in a CD (Yet another use for those AOL 7.0 discs that they keep sending)
:-)
A burned out light-bulb causes some interesting things to happen as well
Jesus used to be my co-pilot, but we crashed in the mountains and I had to eat him.
This is sweet! I could forge my own One True Ring - Deep inside Mount Panasonic, a master ring was made on High-Power to rule them all!
I don't know about you, but I'm going to be checking the temperature of my pizza rather more carefully in future...
Who in the world microwaves pizza? It gets very soggy and loses almost any redeeming qualities.
"It must be stated that, at the out-set of these experiments, the researcher was completely ignorant of microwave technology."
Ack, I'm caught between rolling my eyes and saying "Well, a lot of progress is made by people who don't know what they shouldn't be doing."
What the hell, good luck guys. If you plan on reaching 900 degrees, I strongly suggest tearing apart that microwave and rebuilding it out of stuff that can take the heat.
Democrats or Republicans. They are both taking us to the same place and they are not afraid of us anymore.
Now you can steal gold and silver jewelry and smelt it to some other form within minutes of returning to your evil lair. On the legal side of things, perhaps there will be no more waiting a week for the dentist to make a gold crown. Simply make the ceramic mold, insert gold alloy, microware for a few minutes. Viola, instant gold crown.
Article X: The powers not delegated... by the Constitution...are reserved...to the people
microwaves are high voltage, high current devices. they can kill you EVEN IF THE POWER IS OFF AND THE DEVICE IS UNPLUGGED (ex: by discharging of a large capacitor). Unless you really know what you are doing, don't open one up. i've been trained in servicing electronics, and even i wouln't go near one of these things.
see: Notes on the Troubleshooting and Repair of Microwave Ovens for more information.
When you are cooking pizza in a microwave oven, it won't reach such great temperatures because pizza is not a very efficient absorber of enrgy, newer microwave ovens have sensors inside to prevent the microwave from getting that hot, and if you removed those sensors, by the time the pizza actually got that hot, it would be a nice balck colour. However, when something such as water ( a very efficient absorber of heat is used ) care must be taken to prevent something such as this [abcnews.go.com]. ( Water being superheated then flash boiling when something is placed in it )
And so we go, on with our lives
We know the truth, but prefer lies
Lies are simple, simple is bliss
This ranks right up there with using liquid oxygen as charcoal lighter. The mpeg is quite impressive, though.
The dogcow says "Moof!"
well, this is fine indeed. I can finally realize my dream of melting basalt at my house. But now what to do with all those old CDs I was keeping to make a solar oven with?
Info on the elements, OT but close (no bronze or basalt, but iron: http://www.speclab.com/elements/ Has melting points and a lot of other data apparently cribbed from CRC.
P.S. don't forget this
There's nothing wrong with heating up a metal in a microwave, that in itself will not ruin the unit. What is a big problem is the heated item melting the inside floor of the oven due to (drum roll, please), HEAT! The item gets hot, and melts a big hole in the floor, therefore ruining it. So go ahead and heat metals in your microwave, just don't let it touch the insides directly. That means using a plate, cover, etc.
Damn ... now does anyone have an Open-Source ceramic shell slurry mixture?
Karma? Karma? I don't need no stinkin' karma.
Troll or dumb...
I just can't decide...
Tim
Omnia vestra castrorum habetur nobis.
Back in 1981, I built a small clothes dryer from a microwave. I drilled a hole in the front glass, placed a vacumm tube through it, with a vacumm pump on one side, and a vacumm flask in the m-wave. I them tested various fabrics with differing amounts of H20 in them. Amazing that a jean leg dryed in 15 minutes, tee-shirt in 5, a wool sleve in 25 minutes (low heat to avoid shrinkage). Based on energy calculations, it used about 2/3 the power and was running at lower overall temperatues (I suspected that local temps ran over boiling, but then again they do in a dryer).
I wish I had the money back then to persue the idea.
*assuming* that this technique ultimately becomes stable and useable in a home microwave (safety, cost, repeatability, yada yada), this would open up wonderful avenues -- imagine making your own jewelry and robotics parts without building a blast furnace!
I bet there could also be plastics that would be compatible with this process. Excellent for product prototyping.
The reality, though, is that it'll never be commercialized to the extent of becoming a hobbyist kit. Too bad.
... if the microwave ran cooler (pun intended).
If the microwave could somehow have a thermostatic control, I could take a bag of grade-5 bolts and nuke them to a grade-8 tensile strength. The button for 1040-steel alloy can go next to the popcorn button.
:-)
To properly control the grain structure of the metal, the heating & cooling processes have to be controlled precisely for temperature vs. time (very non-linear and not instinctive). Introduce a quenching process in the microwave, and I bet you could make some serious bucks selling/operating this thing.
The dogcow says "Moof!"
Notice how the crucible and insulating assembly looks over exposed in the photos linked from the article. I wonder if this is because they are emitting a large amount of IR? This would be invisible to the eye, but visible to a CCD camera, even through a the cheap plastic filters they use.
Take one green grape (not seedless) and cut it width wise, leaving the skin on one side intact so it forms a sort of hinge. When you lay it in the microwave it should look like a pair of breasts.
Run the microwave for 10-15 seconds. The grape will spark and then burst into flames. Many all-nighters in college were punctuated with breaks to show people this wonderous phenomenon in the dorm microwaves, and now you too can try it at home. yay.
That's what the microwave at work is for!
I'm trying to teach myself to set people on fire with my mind... Is it hot in here?
now on slightly related topic
When food, (containing water, a very efficient absorber), is placed in a microwave field having a frequency of 2.4 5GHz, virtually all the microwave energy is converted to heat.
Now this raises all sorts of interesting safety questions about wireless networking, as well as the current generation of wireless telephones I see down at Staples, etc.
"It is a greater offense to steal men's labor, than their clothes"
You don't melt iron. You melt -steel-, which is an alloy of iron and carbon, with a variable melting point depending on the carbon content(more carbon, lower melting point).
The question about the microwave use is not my issue. ;)
In space, no one can hear you moo.
Other than that, the technique sounds unnecessarily laborious and complex. There are easier ways to melt metal, even at home. Thermite, for example, should appeal to people who like fireworks. Basic textbooks on inorganic chemistry, mineralogy, and metallurgy can tell you how. (Don't people learn this stuff in high school chemistry anymore?)
It's still sacrilege...
Buckets,
pompomtom
"There's an exception to every rule. Except for some rules"
A serious problem with pouring molten metals is the risk of moisture in the moulds. For example, if a fly happened to be in the mould when the metal was poured, the metal would explode from the moisture with enough force to hit the ceiling. I sure don't want to be in a room when its raining molten metal!
Yes, you are right, microwave radiation levels from an oven and the high voltage levels are unhealthy. However these things are usually quite reliable, although there is usually an internal fuse that can blow.
What concerns me more is that the heat build up from a glowing crucible of molten metal is somewhat more than from a pizza. Such heat isn't going to do the cabling or the door much good.
Who needs a blast furnace for making jewelry or robotics parts? Unless, of course, you are making them out of steel and all you have is a bunch of coal or coke and iron ore
would someone please make a 1000 watt wireless radio transmitter.... PLEASE!!
When i used to work as a repair tech for a local clone computer shop, i used to go and grab all the aol disks outta the modem boxes, and nuke em in the back room nuker (5 secs does it nicely), then tack em up on the shop wall. When customers would ask what the hell had happened to the cd's, i said it contained a vicous trojan horse that destroyed your tcp/ip stack (this was back when aol software had a hugely nasty habbit of utterly corrupting your ip stack) and that i was sterilizing the cd so that people didnt accidently destroy their OS. Customers would nod agreeingly afterwards.
Lawyers, MBA's, RIAA? A jedi fears not these things!
I mean, this is really cool and all -- but i am sure this is violating an EULA somewhere. ;-) Just be glad that GE is not all up on the M$ behaviors
My life in the land of the rising sun.
I've no quarrel with frozen pizza designed to be microwaved. When hunting and gathering one must accept what one finds. But you savages who defile perfectly excellent cold left over pizza have no place in a civilized society. Some social ills make me wonder what horrible childhood pain would cause a person to behave in such a disturbed manner. But those dysfunctional individuals microwaving delectible left over pizza, clearly they must be shot, incinerated, with their ashes encased in glass rods, buried under a mountain or maybe a salt flat, then covered with lye and never spoken of again.
When people ask "What's this world coming to?" you can be sure that people who microwave perfect precious left over pizza are at fault. Filthy animals!
--Jimmy has fancy plans; and pants to match.
Using an industrial microwave (5kW) with Nitrogen piped through a bed of Al powder I got a max of 1470 C before solid Aluminium Nitrate was formed. Temp possibly got up to 1600 C but thermocouple melted. arse. Seemed that key to getting ignition (or melting) was retaining heat. got one reaction at approx 1KW after 15 mins using carbon powder packed between 2 tubes |c| al |c| |c| al |c| Have u tried Au/Ag powders (heat much faster than solids - sorry if already posted)
Microwaves in a microwave oven are using a frequency that matches the vibration frequency of the O-H bond in water. Now if a microwave should be converted into heat, it must hit a molecule, where it can leave the correct energy. This is quantum mechanics, so only the precise amount of energy can be transferred to the vibration. If the wavelength of the microwave doesn't match, energy will not be transferred.
Now the described experiment used several different containers for the metal. These containers absorb the microwave and convert them into heat. To obtain the best container material, you should look for materials whose vibration energy of some of its atom bonding matches that of the O-H bonding in water.
The O-H bond has been chosen as most food contains water. Materials without water will not heat in a microwave oven. (Unless it contains molecules that match the frequency in other ways).
-:) Oh no - not again.
www.rednebula.com
Oh, you're all geeks.... the lot of you... Not nerds like the site says, GEEKS!
The worst thing about this is that some of you here will actually think this will Get you chicks!
Argh! I need my pills? Where are my pills?
/^[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,4}$/i
Didya actually READ the article? Didn't think so. The crucible is specifically designed to absorb the energy of the microwave, so no short circuiting/sparking.
:)
Go read it, you'll learn something!
And the people shall be oppressed, every one by another, and every one by his neighbour Isaiah 3:5
Re, Molten metal will burn through unprotected skin....I sure don't want to be in a room when its raining molten metal!
I have seen it happen on a small scale. One day many years ago we young idiots were casting bullets for the long rifle and poured the lead into the mold while it still had a bit of water in it. It exploded out and a drop of it hit my brother's arm. Yes, it did burn right into the flesh, and that was only lead with its front-porch melting point.
If its trajectory had been slightly different it would have hit his eye.
You be careful, now, hear?
Injection molding is more than just the heat, it's the pressure too. Otherwise the polymer molecules don't line up, and you get weak plastics, especially at bends and corners.
so if the metal doesn't heat up, ummmm.... how does it melt???
The inner layers of the mold (including the cup holding the metal stock) contain carbon fibers and ferrite granules, which absorb the microwave and warm up. From there, the heat has to get into the metal by conduction.
Explanation: microwaves are oscillating electrical and magnetic fields, with a wavelength of a few inches. When these hit a good conductor (the metal stock or the walls of the microwave chamber), current flows just under the surface of the metal, generating electromagnetic fields that cancel the incoming microwaves and transmit them back. In other words, the metal reflects the microwaves, and only a tiny percentage of the heat is absorbed by electrical resistance. So you can't melt silver by just putting it in an invisible-to-microwave ceramic crucible and nuking; you need something that absorbs microwaves instead of reflecting. (Food, water, and poodles are all conductive but too high resistance to reflect microwaves well, so they are good absorbers, but make terrible crucibles. 8-) Reid also tried graphite crucibles, but while graphite is higher resistance than metal, it is still not enough resistance for good absorption.
By mixing carbon fiber into ceramics, Reid made a crucible absorb microwaves, but it wouldn't get hot enough - either the carbon fiber isn't a good enough absorber, or it's resistance changes as it heats up until it isn't effective anymore. So he went for another absorbtion mechanism: under the right circumstances the magnetic field of a magnetic material will oscillate in response to an impinging field. This basically requires the atoms to rotate back and forth, and heat is generated in the process. The magnetic field of the material lags behind the impinging field (called "hysteresis"); plotting the impinging and internal field on X and Y axes, the internal field traces out a rough quadrangle instead of a line and the area enclosed = lost energy = heat.
The magnetic ferrite granules Reid used were not good enough absorbers by themselves; I suspect that the material is too magnetically "hard" so it wasn't responding to the microwaves at room temperature. But a layer of carbon fiber/ceramic warmed up the granules, probably making them "softer", and then they absorbed microwaves quite well. Reid found that the maximum temperature was 1100C, enough to melt cast iron, but not steel. (Excessive carbon makes cast iron lower melting but brittle.) He says the ferrite "fluxes" at this temperature - I think that means it melts. At any rate, all magnetic materials will lose their magetism at some temperature.
So it gets hot enough for jewelry work, and maybe a few other things. (See the article for the practical details of building and insulating the crucible/mold.) Could it get hotter with different materials? You need something that remains a good absorber at high temperatures. Maybe a composite of platinum resistance wire alloy fibers in ceramic?
Water evaporates at lower temperature as the atmospheric pressure reduces. You wanna conserve loads of energy? Pump the air out of the dryer and apply a little heat.
Oh shit, patent, patent...
Government of the people, by corporate executives, for corporate profits.
How does a post that hasn't been moderated get moderated down as "overrated"?
I've had the experience of rating a post at + 1 ("funny", IIRC), clicking the Moderate button, and seeing it actually get moderated -1 "overrated". I'm sure the little rating window was correct before I scrolled down to the bottom to fing the moderate button, so seems like there might be a bug in the code.
Doh.
Government of the people, by corporate executives, for corporate profits.
Great idea until the first article of clothing with a zipper or metallic buttons gets fed in...
Still, perhaps a dedicated sock/underwear dryer would be of some use. You could make a very small combination unit that would wash, then dry, and spit them out - you'd only need one pair of socks!! Or at least be able to get a clear pair of socks in about five min if you realized you needed to do the wash the night before.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
Hmmmm
At my university the microwaves in the student accomodation had warnings on them not to dry cloths as they could catch fire.
Dunno if there is any truth in that, but I suppose in a microwave without a turntable (yes, these were cheap micowaves!), localised points could get very hot....
Anyone quoted by a reporter knows how little they understand
Don't believe what you read is the truth.
Now you can make your very own! The old US penny is made of 95% copper, 5% zinc. The new ones are 97.5% zinc, 2.5% copper (the zinc is on the inside, the copper is in a thin outer layer). Zinc melts at significantly lower temps than copper...so scratch a new penny down to the shiny zinc, nuke it in the crucible, and out will flow the molten zinc, leaving a hollow penny!
Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
More uses: Drying out silica gel and refreshing zeolites. Says so on the can.
More fun: Microwave grape racing. Steam builds up inside, and jets out the stem hole and the grapes scoot around inside the microwave. Ocasionally, the stem hole is too small/plugged with seeds/still has a piece of stem inside, in which case they explode on the starting line.
Cool! How do you recover the zinc? I assume you add a base, and precipitate out the zinc.
Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
Yes. Your clothes will catch on fire.
In a pinch, you can microwave your socks/boxers to kill the little nasties that make them smell funny. Even with a turntable, however, leaving them in for too long *will* result in a fire.
Not that I speak from personal experience or anything. I, uhm, heard this from a friend.
Why learnsomething when you can just ger religous about what somebody says?
Don't give me a lengthy reply, I can't be bothered. Instead, just give me the gist of it.
;)
The Kruger Dunning explains most post on
Whoa glass too? Hmm, now I'm intrigued even more. I really appreciated the original post even if the work isn't totally original. It's refreshing to see people who actually try something without assuming that the experts already have everything all sorted out.