# silver thum cell built, but not functioning well



## pljohnson (Nov 11, 2010)

I put together a 2 1/2 gallon thum cell to refine silver in. Ive got a stainless steel sheet on the bottom, which is bent up the side to make negative connection. I placed about 100oz of 98-99% pure silver in the anode basket with muslin cloth. For my candlestick ive just got a 10z bar of silver with a sterling silver fork handle coming out of the top. For my power I bought a 25 amp plating rectifier. Ive tried setting in on about 3.5- 4 volts, but the amperage and volts do not register on the rectifier when I hook up the positive and negative, so I do not know what is actually going through the cell. As for my solution I did 4 oz copper per gallon and 6 oz fine silver per gallon. After nearly 4 hours all I have is a thin layer of crystals with no build up. It seems after 2 hours I really havent had much more build up at all. Forgive my complete ignorance in this matter as I am new to silver refining, but what could be the reason for my very little growth in crystals?


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## lazersteve (Nov 11, 2010)

Sounds like current is not flowing or not enough is flowing. 

This can be caused by poor connections at the rectifier, cathode, and/or anode, this can also be high cell resistance or a defective rectifier. Verify you have voltage at the ends of the cables with a volt meter.

If you have voltage at the leads, then switch the meter to measure resistance (ohms) and measure across the anode and cathode contacts of the cell with the rectifier disconnected. If you have more than a few ohms on the meter when testing your electrolyte is the problem or you anode/cathode connections. Spacing of the anode and cathode can also increase the cell resistance. Reduce the gap between your anode and cathode and see if the resistance decreases to below 5 ohms, optimally around 1 ohm. Typical electrode spacing is 4 inches.

If all of the above checks out check your rectifier with the volt meter for output voltage and amps output with the cell disconnected.

Steve


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## Harold_V (Nov 12, 2010)

In my opinion, you don't have anywhere near enough silver in the electrolyte. I used to use 30 troy ounces for my cell, which held, at the very most, 2½ gallons. It may have been less. It's been too long to remember.

Harold


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## goldsilverpro (Nov 12, 2010)

Check the fuse on the rectifier.

It is common for the muslin to contain size. Because of this, it can take a couple of hours before you get any current flow.


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## pljohnson (Nov 12, 2010)

well I checked the resistance and if my meter is correct the resistance is 60 ohms. Obviously too high. My electrolyte solution is as I was told to have it, so I have a hard time believing the elecrolyte is bad. I bought 304 stainless for my cathode, any way this could be my problem.


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## Oz (Nov 13, 2010)

Your 304 stainless is fine for a cathode. 

I'm not saying your starting electrolyte is “bad”, but it is not good. It will probably work, but is way off from the norm and will have a short life. I usually start off with 3 troy ounces of silver per liter and if I add copper it is only 5 grams per liter at the most. So for your 2 ½ gallon cell I would have started with 28.5 troy ounces of silver and if I added copper 1.5 troy ounces at the most. 

With your high resistance it is probably the sizing on your cloth that GSP mentioned that is your problem. It can take several hours sometimes to overcome the sizing and get good current flow. 

Another possibility is that all is fine and you are making silver at the cathode only to have it go back into solution. I say this because of your electrolyte composition being off that you may also have made it with a lot of free nitric still in solution. That too would eventually be overcome as the silver levels built up in your cell. Are you having your scrap silver in your anode basket being consumed?

The greater the detail you give us on your set-up and “how” you made your electrolyte, the better we can help you.


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## Harold_V (Nov 13, 2010)

pljohnson said:


> My electrolyte solution is as I was told to have it, so I have a hard time believing the elecrolyte is bad.


Not so fast! 

When all else fails, you should read the book Silver, Economics, Metallurgy & Use, Butts & Coxe. 

If the source of your information is wrong (and I think it is), you need to pay attention to those that have knowledge, not those that think they do. How much silver has your information source processed? There are people on this forum that have processed tens of thousands of ounces. 

Do not be mislead by those that proclaim themselves as knowledgeable in refining. Rarely does anyone know what they're talking about unless they have experience in the field. All too much bad information is floating around and accepted as gospel. I offer you, as an example, the huge number of people that suggest you process e scrap using AR. That is wrong----very, very wrong---with rare exception. 

Prewashing a fabric filter is always a good idea. 

Harold


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## butcher (Nov 13, 2010)

pljohnson,
Something you said above, your power supply about 4 volts on setting and that your gauges volts and amperages do not read on the power supply, did they work before? This leads me to suspect the power supply, or the load (your cell), if you have an amperage scale on your voltmeter you can put your meter in series with say the anode lead and see if you have an amperage draw. Or add a load to power supply like a light bulb and see if power supply will light it, and do gauges on your power supply work with this load?

You said you measured 60 Ohm’s for resistance of your cell, and if you are supplying 4 volts your amperage should be close to---4V / 60 ohm = 0.06 amps or 60 milliamps, this amperage is way too low to move much silver, more silver in solution will lower resistance of cell and increase amperage flow. Here is where the suggestion above of more silver Ions in electrolyte very possibly the problem. And this suggestion came from some very experienced refiners.

I do not have experience with the silver refining cell, but from what I remember reading from those that do, I think they say Amp’s per electrode area, not milliamps.

So here I would suspect maybe your power supply may not be the problem,
Also the connections can affect resistance, and the connection of your candlestick to silver in the cell, poor connections equal high resistance.

Also make sure power supply is working properly, a bad power supply may read a voltage output on a meter (no load to speak of) but can peter out when a load is added to the power supply, bad connections (high resistance) can also cause this. The Voltage should be checked with a load added. 

Good luck keep us posted many of us will learn from this discussion.


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