# Deplating Silverware with H20 cell



## Dach Savage (Jul 11, 2014)

Hi all, I have been working on trying to deplate silverware as simply and inexpensively as possible; when I ran into Modtheworld's H20 cell idea. I set up a 12 cup coffeepot with with a thick sterling rod as a cathode and the to be deplated item as anode. Started with RO water to keep it fairly consistant and my 13.3 V x 30 amp bench top power supply. When I switched on the power the handle on the plated knife started to develop a white "cloud" within a few minutes. After a few hours the item showed evidence of deplating and developed a blackish grey coating that would easily wipe off with a paper towl. After I looked at the residue on the towel I realized it looked like graphite so I decided that I would simply just brush off the yuck with an old toothbrush that I cleaned off in the electrolyte (H20). I continued processing a half dozen more knives and the all seemed to deplate well but still had the problem with the blackish residue that would only come off with a scrubbing. At this point the electrolyte was dark blackish grey and fairly opaque with a black mud forming on the bottom of the container. On the last few items I used a bait bucket aerator to see if agitating the solution would help but it didn't seem to help with the anode scum. I forgot to time the last few knifes with agitation but got a vague impression that the aeration might have slowed down the reaction. I am really hoping to find the magic answer that will allow me to simply dangle the silverplate items in electrolyte bath and pull out clean (wishful thinking?) Any thoughts on what the anode scum might be or how to keep it from building up (possibly lower the voltage)? Secondly any ideas what the blackish precipitate might be at the bottom of the container and how best to reclaim the silver values from it?


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## solar_plasma (Jul 11, 2014)

All answers are given in some of my last posts in this thread. They have not been commented very much, so far it will be the best answers, you will find. I just refined approx. 100-150g of gray silver powders from the black mud. I went the AgCl-NaOH/Karo syrup route with extended HCl and hot H2O washes of AgCl. The HNO3/cementing on copper route might be better. Hard to tell.


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## Dach Savage (Jul 11, 2014)

solar_plasma said:


> All answers are given in some of my last posts in this thread. They have not been commented very much, so far it will be the best answers, you will find. I just refined approx. 100-150g of gray silver powders from the black mud. I went the AgCl-NaOH/Karo syrup route with extended HCl and hot H2O washes of AgCl. The HNO3/cementing on copper route might be better. Hard to tell.



Hi Solarplasma,
I did indeed read everything I could find on GRF forum postings but I apparently missed yours. I don't think I am adept at navigating this site yet. Anyway, 100-150 grams? Wow, how many lbs / kilos of silverware did it take to yield this much silver? I also used a purified water as I agree, there is likely some chlorine in Mod's tap water. Did you have a problem with the black sludge on the deplating items? Any success in eliminating or dealing with this simply? I tried agitating the electrolyte with air and am thinking of trying heating the solution. Any thought on heat? Maybe a temp suggestion? If I come up with something that works I will post results. Thanks Dach.


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## solar_plasma (Jul 11, 2014)

a 2,3 kg silver plated tray, all in all I calculated 180g silver

The method I used on this run:

filtering the dark mud (mostly Ag2O, some AgCl), clear electrolyte back to the cell
let it sit for a couple of days in HCl (actually some weeks I think)
wash, wash, wash...first HCl, then hot water until no copper can be detected anymore
NaOH/karo syrup method
let it sit for a day, decant, wash until filtrate is clear, colorless and neutral

this results in gray silver powder, but yet I can't tell how pure it is


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## Dach Savage (Jul 11, 2014)

By the way, on the voltage question I have a power supply that I built years ago for charging my EVs that will allow me to go 0-60 Vdc in 10 x 10 steps and amperage capability up to 20A on the top end, so I can experiment with various voltages if anyone wants to chime in on this thread. My hotplate will easily boil the pot full of water so temp is also controllable. Dach.


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## solar_plasma (Jul 11, 2014)

I would not use over 25V DC! I stated this also in the other thread. DC is more dangerous than AC, you will cling to the cell until dead, if you should touch it.


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## crbaker41 (Jul 12, 2014)

I use a computer power supply and a crock pot on high it deplates in a hour but you need to flatten the silverware


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## Geo (Jul 13, 2014)

DC current is less dangerous than AC current as long as the amps are low enough. Even DC is dangerous at higher amps. A taser uses DC current as well as automotive systems. Anyone that has been knocked stupid from a spark gap of a running engine can tell you how strong the current is. One volt can kill with enough amps.


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## solar_plasma (Jul 13, 2014)

> that will allow me to go 0-60 Vdc in 10 x 10 steps and amperage capability up to 20A



In our schools, over 25V are forbidden to the pupils. 60V with up to 20A (don't know how much will go through the skin) is a lot.


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## solar_plasma (Jul 13, 2014)

> A taser uses DC current as well as automotive systems.



They are pulsed! Not like the DC current from a steady power supply.

I just don't advise it. Not more, not less.


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## butcher (Jul 13, 2014)

It is current (amperage) that is dangerous, not the voltage.
We can have a high voltage (AC or DC) with a low current and it just hurts when we get shocked, Example thousands of volts with an extremely low current, will just give you a good shock, but it will not stop your heart.

A small current and even a very low voltage can kill you if the current is more than a few milliamps. Resistances of skin, dry more resistance, wet less resistance. the resistance of your body, can determine how much available current flows through your body or your heart.

A higher voltage can make it easier to get past that resistance, for the current to flow through your body of heart.
Just a few milliamps of current can easily stop your heart, no matter how high the voltage is, or whether it is from an alternating or direct current, how easily this very small amount of current will stop someone’s heart can also depend on the persons physical condition, or the condition of their heart, and at what part of the heartbeat this small current is applied to. 

Current will also contract our muscles. As the AC voltage alternates back and forth, in my country at 60 cycles or Hertz HRZ or 60 times a second (60 positive pulses and 60 negative pulses a second) it would contract my muscles 120 times a second, if I am standing in water and pick up an electric saw the AC shock makes my arm muscles, and hand muscles constrict and grip on the saw 120 times a second, making it hard for me to shake the saw out of my hands, (not a fun feeling I can tell you from experience), DC voltage will not pulse your muscles, but can make your muscles clamp them down on the saw, making it even harder to shack it of your hands grip.

You heart is a muscle, that pulses or beats, an externally applied current can make it beat at the wrong time or constrict the hearts muscle not allowing it to beat or pump blood, or make it stop beating by pulsing it or shocking it at the wrong time of its normal beat.

AC current will pulse the heart muscle from the externally applied source current, DC can constrict the heart muscle from the external DC applied current not allowing it to beat...


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## the iron dwarf (Aug 26, 2014)

Geo said:


> DC current is less dangerous than AC current as long as the amps are low enough. Even DC is dangerous at higher amps. A taser uses DC current as well as automotive systems. Anyone that has been knocked stupid from a spark gap of a running engine can tell you how strong the current is. One volt can kill with enough amps.



the supply to an ignition coil on an engine is normally 12v DC but the output is not, it is many thousands of volts at only a couple of milliamps caused when the field collapses in a tesla coil

these days it is done electronically but on older systems the contact points open breaking the circuit to the coil primary and that causes a huge spike on the secondary , it is a very high voltage but a very low current, a high current but low voltage will not cause a spark at the plugs so the engine will not run but a high voltage can cause a spark to jump the gap.
lightening is at a very high voltage but also a relatively low current, shorting out a low voltage high current supply like a car battery will cause sparks but unless shorted out a spark will not jump across your battery
electric fences and tasers also have a dc supply but the output is nothing like the same as the input and all work on the same principle as a tesla coil
check the resistance of flesh and see how few millimeters apart electrodes have to be for any current to flow, you can quite safely place your hand across the terminals on a car battery that can easily put out 500 amps or more ( but drop a big spanner across them and it will melt ).

of course if you were to place electrodes on your heart within a few millimeters of each other a lower voltage will affect you more, from outside your body 48v DC is not likely to do you any harm unless you have had an inverter surgically implanted in you.
check Ohms law for current to voltage to resistance and measure the resistance from your right hand to your left hand, wet or dry, then try the same from your thumb to you little finger on one hand wet or dry, then try it from one side of a finger tip to the other and note the resistance, you can they work out what voltage you need to get a current to flow in any of those distances, it does not matter if the supply can be 500 or 1000 amps the current taken will be dependent on the resistance and voltage and for one volt to affect your heart first your heart would need to be squashed to probably less than a millimeter thick in which case you would not be concerned about electricity

how do you think people change a rod in a stick welder putting out 48 to 75 volts at 250 amps ( and that is not a large one either ) older oil cooled ones were often switchable from 55, 70 or 90 volts output as well as current control


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## Geo (Aug 27, 2014)

The skin is a great insulator. Have you ever placed the electrodes of a small 9v battery against your tongue? It has a jarring effect to say the least. The tongue is wet and the saliva has salts which lowers the resistance. All of the amps stored in the small rectangular battery discharges into your tongue. It's a very wicked shock and not something you would like to repeat. It's the same with electrodes inserted under the skin. I have gotten a shock from touching the positive on a car battery but my body was against the body of the car. Even though the shock was only a tingle, it was still very unpleasant.


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## DNIndustry (Nov 17, 2014)

i have some 5v 60 amp powersupplys would they work? make less gas? or is 12v required.


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## solar_plasma (Nov 17, 2014)

Might work a little slow.

This method is different from our other cells. Here we use the anode to produce oxygen, which reacts with the silver layer (anodizing). So, up to maybe 12 to 24V (depending on the electrode distance and conductivity of the water electrolyte - i used 2-4cm in my experiments) most of the oxygen will react with the silver.

Only my two cents founded in my observations and the documents posted in this thread.


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