# some ideas - not serious



## solar_plasma (Aug 25, 2014)

Just got two funny ideas while driving home....

1) Put gold plated pins in a quarz tube with graphite contacts, pump a weak air flow though the pipe, that is semiclosed at the and with glass wool. Send a lot of amperes through the pins till they are white glowing. The gold should condensate at the end of the pipe and into the glass wool. Basemetals would mostly oxidate. Stop the process, when no visible gold is left in the starting material.

2) same tube, without anything but air flow and an arc between the graphite contacts. The air is lead through flasks with water or hydroxides for making nitrates or nitric.

Ok, those ideas are meant for entertaining, not very serious. But would not wonder, if this works to some degree. Nr. 2 I have tried before. You can measure a lower pH after quite a short time.


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## Geo (Aug 25, 2014)

I have one for you. Since graphite has resistance to electricity, why can't you load a graphite crucible and use it as an electrode to melt your precious metals. Anyone that grew up in the rural south has used the graphite rod from a "D" size battery and a couple of wires hooked to the battery to solder a radiator or heater core on the side of the road. It glows white hot.


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## solar_plasma (Aug 25, 2014)

Yeah, I know this method, as kids we did this in boring school lesson with our pencils 

My idea is to vaporize the gold from the surface and condense it to the glass and glass wool.


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## rickbb (Aug 25, 2014)

solar_plasma said:


> Yeah, I know this method, as kids we did this in boring school lesson with our pencils
> 
> My idea is to vaporize the gold from the surface and condense it to the glass and glass wool.



It would work better under vacuum. The more vacuum you draw, the less current/heat you will need to make a gold vapor and the easier it will be for the gold vapor to deposit, (condense), out on the glass.


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## solar_plasma (Aug 25, 2014)

But copper has a lower boiling point. Maybe in an oxygen flow, burning all base metals to ashes. Vaporizing gold will be caught by the glass wool. The base metal oxides will readily dissolve in almost any acid.

As I said, it's not very serious. I think, I should read a bit about sputtering.


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## solar_plasma (Aug 25, 2014)

Too slow....


But I would like to see some pins burn in pure oxygen and see, where the gold will go.


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## Geo (Aug 25, 2014)

If I'm not mistaken, sputtering is vaporizing a metal in a vacuum with plasma. It then condenses out on your target.


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## Anonymous (Aug 25, 2014)

Along the lines of not necessarily serious I've always wondered if I could make a furnace based around my plasma arc cutters.


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## rickbb (Aug 25, 2014)

Geo said:


> If I'm not mistaken, sputtering is vaporizing a metal in a vacuum with plasma. It then condenses out on your target.



Yep, 3 ways to vapor deposit. 

Evaporation, draw a high vacuum, 10 to the - 8 torr, then heat the source beyond it's vapor point, at that vacuum, which is very different than at 1 atmosphere. Heat up the source and the vapor cloud fills the chamber and coats everything with a condensate.

Sputtering, similar to evaporation but with a gas like argon in the vacuum chamber. Needs less vacuum, about 10 to the -6 torr or so. 

Ion bombardment, or Ion sputtering, again in a vacuum chamber but the source is blasted with an ion beam of some sort to create the vapor particles instead of heating in a crucible. So it needs even less vacuum, about 10 to the -4.

Note the pressures and energy to vaporize the source vary greatly based on the material. And in these examples I'm mostly guessing based on what we did when I worked in the CD plant. We sputter deposited Al and Au on compact discs on the production line. I did nickel evaporation in the mastering room.

The sputter chambers on the CD line used mechanical two stage turbo pumps for speed. And the chambers were really small, just big enough for a single CD and the source, which for some odd reason was called a target in the trade.

The evaporation chamber held about a cubic meter of volume. We used a standard mechanical pump to get the pressure down to the 28 inches Hg, then a cryopump, (liquid helium), took over to take it down the set pressure. Which if my bad memory isn't completely off the wall was 2X10 to the -6 torr. Supposedly it was near outer space vacuum and had only 3 molecules of water vapor in the cubic meter space. Took almost an hour to make a shot of 3 masters, 45 minutes to get it down to the target pressure.

Sometimes I miss that work, but not the company I had to do it for. They were so good they are now out of business. And not because people stopped buying CD's either. lol


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