GOLD SMELTING FLUX
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This post is very interesting. I strongly advise those of you that do any smelting to investigate the concept.
One note. In the video, the operator is shown stirring the material mid way in the operation. The harsh reality is that induction melting (that's what a microwave is, a small induction furnace, albeit high frequency) does not require stirring. The eddy currents developed provide almost violent stirring action.
This setup could be the solution for those that have a desire to do their own assays, but do not have the capability to melt. It would not serve for cupelling, however.
Harold
One note. In the video, the operator is shown stirring the material mid way in the operation. The harsh reality is that induction melting (that's what a microwave is, a small induction furnace, albeit high frequency) does not require stirring. The eddy currents developed provide almost violent stirring action.
This setup could be the solution for those that have a desire to do their own assays, but do not have the capability to melt. It would not serve for cupelling, however.
Harold
samuel-a
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Harold_V said:
May serve well with PGM's black, won't you say so Harold?
I had a thought once of maybe using microwave for melting/smelting, but tossed that idea right out of my head, maybe it time to explore it again...
It seems too easy though... what are we not knowing?
A
Anonymous
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About 6 months ago,I built several different microwave kilns,using different products.I did not purchase anything from an online seller,I made them myself.They work well if all you are trying to do is melt something.In order to smelt something,it requires a powerful microwave.And Harold is correct,it does not work for cupelling.Harold_V said:
I do not advise using this method for anything we do,that is why I never mentioned that I had built several different versions.If you have a high power microwave,it is a neat experiment,but it had better be a disposable microwave,or you had better plan on not doing it very long,or often.
As someone that has succesfully done this several times.....I'll stick to my torch and kilns.
Acid_Bath76
Well-known member
I looked into this less than a year ago, and dismissed the idea after reading some of the initial responses on this forum. Too bad I didn't research further. I have to say, this might be a viable option for someone looking for a compact, low profile, way to melt. I might give this a shot with one I can get from a thrift shop, or goodwill. Well see, right now I have enough on my plate. Interesting stuff though!
A
Anonymous
Guest
Yes...If all you needed was something to melt your refined gold,then it would work pretty good.I used various ceiling tiles and got good results,but you can try different materials and it will still work.
Geo
Well-known member
i talked to a guy that has done this and he used Cellpak insulation around the crucible. its made from newspaper impregnated with fire retardent chemicals. you cant burn this stuff with a torch.
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It may have that capability, but you'd have to use a crucible that is capable of withstanding the temperatures involved. Those assay crucibles would most likely fail, leaving you in one hell of a mess.samuel-a said:
If you're not familiar with induction heating, as particles get smaller and smaller, higher and higher frequencies are required. Most any substance can be heated, assuming you provide the proper power and frequency. Given the fact that microwave oven operate at a high frequency, they just might be a natural for the PGM's black, assuming you could work out the issues with excessive heat.
Key to success, at least in the one presented, is the extremely well insulated module that is used to house the crucible. Without that, you'd most certainly experience rapid failure of the oven.
Harold
samuel-a
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Good points to consider Harold. Thanks.
I'll sure build a kiln to protect the inner casing of the oven, that very easy thing to do.
Powders ware the first thing that came to mind when you mentioned high frequencies.
I actually have some white clay crucibles, i'm not sure of the composition, i think it's mixture of clay and Kaolinite... anyway, they hold up preety nicly, only start to liquify when Pt does with the oxy torch.
So i assume, since refacory materials do not run currents, the only heating of refactory will occur dou to projected heat of the metal. In any case, i don't mind if Pt / Ir button will get buried in the crucible, they come very cheap for me.
The only thing i can't wrap my head around is the dynamics during the melting, when the metal is molten, how does it still get inspired effectifly by the high frequencies?
I'll sure build a kiln to protect the inner casing of the oven, that very easy thing to do.
Powders ware the first thing that came to mind when you mentioned high frequencies.
I actually have some white clay crucibles, i'm not sure of the composition, i think it's mixture of clay and Kaolinite... anyway, they hold up preety nicly, only start to liquify when Pt does with the oxy torch.
So i assume, since refacory materials do not run currents, the only heating of refactory will occur dou to projected heat of the metal. In any case, i don't mind if Pt / Ir button will get buried in the crucible, they come very cheap for me.
The only thing i can't wrap my head around is the dynamics during the melting, when the metal is molten, how does it still get inspired effectifly by the high frequencies?
When heating items in a microwave you are actually passing a physical wave through a substance. Like shooting an arrow at a target. That’s why a microwave door has all them dots on it. It’s to stop radiation leakage. The cooking chamber itself is a Faraday cage which prevents the microwaves from escaping. The door usually has a window for viewing, but the window has a layer of conductive mesh some distance from the outer panel to maintain the shielding. Because the size of the perforations in the mesh is much less than the microwaves' wavelength, most of the microwave radiation cannot pass through the door, while visible light (with a much shorter wavelength) can.
When heating items with induction heating there is no physical wave. The waves are generated by induction, hence the name. It’s like waving a magnet in front of a iron bar and the electrons aligning to meet the pull of the magnetic field. Remember the trick in school where you run a magnet down a nail in one direction to make the nail a magnet? All the electrons orient themselves from the north and south or vice versa. Now do that 400,000 time a sec !!!! Both are done with magnetics so to speak, but one is bombarded with physical waves while the other occurs within the electromagnetic field itself.
When heating items with induction heating there is no physical wave. The waves are generated by induction, hence the name. It’s like waving a magnet in front of a iron bar and the electrons aligning to meet the pull of the magnetic field. Remember the trick in school where you run a magnet down a nail in one direction to make the nail a magnet? All the electrons orient themselves from the north and south or vice versa. Now do that 400,000 time a sec !!!! Both are done with magnetics so to speak, but one is bombarded with physical waves while the other occurs within the electromagnetic field itself.
The kiln looks like it would be relatively easily crafted from lightweight insulating firebricks, much like LaserSteve's minifirebrick furnace. The firebricks are quite readily available (refractory supplies in the phonebook) and fairly easy to work.
Acid_Bath76
Well-known member
if anybody is using this method, what are you using for the insulation housing within the microwave?
I have not tried melting metal powders in microwave.
Acid_Bath76, please study microwaves well before trying anything, even though we think them safe being used in our kitchens, these are very dangerous if the safety's are compromised.
I use to build and work on communication towers, the AM radio towers set on a porcelain ball, with porcelain insulators in the guy wires, the whole tower is the am antenna, we would have to jump from the ground to get onto the tower to climb it, they told us that if we touched the tower and the ground at the same time we would be fried like a bug in one of those electric bug zappers, once we were on the tower we would have to keep constantly moving or changing the hand we held onto the tower with, as if you held your hand in one spot too long it would burn you, and if you let go with that hand and did not have your self belted to tower you could fall 500 to 1000 feet depending on the tower and how high you were, my hands were burned several times, but never did let go with both hands, they told us it was burning us from the inside out, but we only felt it when it burned the nerve endings on our outer portion of our skin, was also supposed to make us sterile, but I had children so that did not happen, on TV towers there were two types of antenna’s bat wing and monopole, these are poles on top of towers, one you can climb Hot as long as you do not touch certain parts of it (instant death if you did), the monopole type you could not climb and had to keep several foot from antenna to avoid being fried.
since I am talking towers, years ago had a job to put up two antennas, and coax on a 500 ft tower, I was riding a winch line up, with the two antennas and coax up a 500 foot tower, got 60 foot up and the splice on winch line came apart, dropping me 60 foot to hard ground, me tied to a 150 pound weight I bounced about four feet after hitting the ground, had about 1000 feet of 3/8 winch line falling from the tower on top of me beating and cutting what was left of me, first thing I did was look over at the kid who was running the winch (also the college kid who spliced our winch into the tower line I was riding) he just sat starring at me, I kept hollering at him, finally after what seemed like a long time he realized I was hollering at him and run over to where I was and said what do I do, I told him we had a two way radio in the truck call somebody, (funny he went into shock but I did not, later when he visited me in the hospital ask asked him why he just sat there and froze, he said He knew I was dead, then he realized I was yelling at him) I powdered both femur bones in my legs broke some bones in my back. and was cutup pretty good, took four operations before I could walk on my own two feet without canes or crutch or wheel chair, even with rods in the bone centers, worked with four other men good friends who were not so lucky they fell to their death two over 250' and two over 500', as dangerous as that job was I miss it and would still like to do it again.
Well enough rambling on.
They use K-Wool fiber blanket insulation. they also do some modifications to the microwave (seems something to do with fan and stir plate, my memory foggy), also they use a suscepter or receptor of microwave energy (can not remember actual name) these are same thing the hot pocket card board coating is comprised of (I believe you could use other metal powders, or possibly graphite although I remember something about carbon not being that good to absorb microwave 2.4 GHZ.
Acid_Bath76, please study microwaves well before trying anything, even though we think them safe being used in our kitchens, these are very dangerous if the safety's are compromised.
I use to build and work on communication towers, the AM radio towers set on a porcelain ball, with porcelain insulators in the guy wires, the whole tower is the am antenna, we would have to jump from the ground to get onto the tower to climb it, they told us that if we touched the tower and the ground at the same time we would be fried like a bug in one of those electric bug zappers, once we were on the tower we would have to keep constantly moving or changing the hand we held onto the tower with, as if you held your hand in one spot too long it would burn you, and if you let go with that hand and did not have your self belted to tower you could fall 500 to 1000 feet depending on the tower and how high you were, my hands were burned several times, but never did let go with both hands, they told us it was burning us from the inside out, but we only felt it when it burned the nerve endings on our outer portion of our skin, was also supposed to make us sterile, but I had children so that did not happen, on TV towers there were two types of antenna’s bat wing and monopole, these are poles on top of towers, one you can climb Hot as long as you do not touch certain parts of it (instant death if you did), the monopole type you could not climb and had to keep several foot from antenna to avoid being fried.
since I am talking towers, years ago had a job to put up two antennas, and coax on a 500 ft tower, I was riding a winch line up, with the two antennas and coax up a 500 foot tower, got 60 foot up and the splice on winch line came apart, dropping me 60 foot to hard ground, me tied to a 150 pound weight I bounced about four feet after hitting the ground, had about 1000 feet of 3/8 winch line falling from the tower on top of me beating and cutting what was left of me, first thing I did was look over at the kid who was running the winch (also the college kid who spliced our winch into the tower line I was riding) he just sat starring at me, I kept hollering at him, finally after what seemed like a long time he realized I was hollering at him and run over to where I was and said what do I do, I told him we had a two way radio in the truck call somebody, (funny he went into shock but I did not, later when he visited me in the hospital ask asked him why he just sat there and froze, he said He knew I was dead, then he realized I was yelling at him) I powdered both femur bones in my legs broke some bones in my back. and was cutup pretty good, took four operations before I could walk on my own two feet without canes or crutch or wheel chair, even with rods in the bone centers, worked with four other men good friends who were not so lucky they fell to their death two over 250' and two over 500', as dangerous as that job was I miss it and would still like to do it again.
Well enough rambling on.
They use K-Wool fiber blanket insulation. they also do some modifications to the microwave (seems something to do with fan and stir plate, my memory foggy), also they use a suscepter or receptor of microwave energy (can not remember actual name) these are same thing the hot pocket card board coating is comprised of (I believe you could use other metal powders, or possibly graphite although I remember something about carbon not being that good to absorb microwave 2.4 GHZ.
NoIdea
Well-known member
Afternoon All - Microwave ovens can be alot of fun, read up on them first, as they have the potential to do great harm.
Metal containers can be used in a microwave, i have dried forage in aluminium pie trays without any problems, it's not until the pie tray cracks then their is arcing.
So the flux used, may have to contain small very high temp metals or oxides that will create arcing within the flux, the gold powder will also arc until molten, i could be wrong but the arcing could be the key to obtaining the required temperatures, and that's why he had to take it out and stirr. :?:
In saying that, my experiance with microwaves are thus:
Steel wool = loads of sparks,fire, and UV radiation
Blown light bulb(filement detached completely) = tungsten filement melts the glass, preasure inside of bulb blows a small hole, outwards, looks real cool. Show friends and pretend you have NoIdea how it happened :mrgreen:
Metal containers can be used in a microwave, i have dried forage in aluminium pie trays without any problems, it's not until the pie tray cracks then their is arcing.
So the flux used, may have to contain small very high temp metals or oxides that will create arcing within the flux, the gold powder will also arc until molten, i could be wrong but the arcing could be the key to obtaining the required temperatures, and that's why he had to take it out and stirr. :?:
In saying that, my experiance with microwaves are thus:
Steel wool = loads of sparks,fire, and UV radiation
Blown light bulb(filement detached completely) = tungsten filement melts the glass, preasure inside of bulb blows a small hole, outwards, looks real cool. Show friends and pretend you have NoIdea how it happened :mrgreen:
Also read up on microwave suscepter's, these seem to be the key, your powder particle size and amount per microwave wattage, the oxide powders or impurity metals may act as suscepter, but for pure gold powders you would probable need a susceptor in flux that would not render your gold impure, that seems to be a major hurdle, if graphite will not suffice???
it sounds like fun to expieriment with but the ole fashion torch, or gas furnace is just better in my eyes.
it sounds like fun to expieriment with but the ole fashion torch, or gas furnace is just better in my eyes.
Geo
Well-known member
could be aluminum. it decomposes at the temperature that melts gold and has a reducing quality. you have to have aluminum to make good grade steel or the steel will oxidize making carbon. could be the same principle going on here, aluminum powder.
NoIdea
Well-known member
Hmmm, one needs to be careful with aluminium powder and metal oxides, OK if you want thermite, ahhh thermite :mrgreen:
Deano
Deano
I think Butcher and NoIdea are on to something here.
I suspect that the person in the video is mis-using the word "flux" - rather the powder is a good microwave susceptor like silicon carbide. Microwaving heats up the silicon carbide, which is mixed with the gold powder and heats it up.
Not sure if that is a better approach than using a silicon carbide crucible, although SiC crucibles are probably expensive compared to alumina or fireclay or whatever he is using, while SiC powder is pretty cheap.
Now I need to find good insulating refractories and an old microwave in order to try that out...
Gerald
I suspect that the person in the video is mis-using the word "flux" - rather the powder is a good microwave susceptor like silicon carbide. Microwaving heats up the silicon carbide, which is mixed with the gold powder and heats it up.
Not sure if that is a better approach than using a silicon carbide crucible, although SiC crucibles are probably expensive compared to alumina or fireclay or whatever he is using, while SiC powder is pretty cheap.
Now I need to find good insulating refractories and an old microwave in order to try that out...
Gerald
While I'm sure that those writing and experimenting here on the forum are knowledgeable and know exactly what is going to happen I'm still sure this isn't one for the non expert to mess with.
I for one will not be trying any experiments with microwaves and will only even look at this seriously when one of the moderators gives it a full thumbs up as I'm 100% sure this could cause some serious injuries to someone not clued up on microwave energy, but I will continue to follow this thread with interest to see who sorts out the problems and creates the first safe forum model.
I for one will not be trying any experiments with microwaves and will only even look at this seriously when one of the moderators gives it a full thumbs up as I'm 100% sure this could cause some serious injuries to someone not clued up on microwave energy, but I will continue to follow this thread with interest to see who sorts out the problems and creates the first safe forum model.
Acid_Bath76
Well-known member
I'm in the same boat on this one. My interest is peaked, but I'll be watching from the sidelines. If you want it straight from the "horse mouth", give them a call. When I first heard of this method, I did a little research, but microwave technology is a little over my head. For a lot of you guys though, you shouldn't have a problem picking their brain. I would be curious what you could walk away with after that conversation. Anyhow, you guys have a good one. I'm off to class.
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