# cell quit working



## Paige (Apr 15, 2007)

My cell was working fine, followed all directions. This a.m., when I went to pop the top off and strip some more, no fizzing. Should I add more sulfuric acid. I don't think the cell is anywhere near full as the cathode shows vistually no wear.

HELP.

Paige


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## goldsilverpro (Apr 15, 2007)

If it worked before, it should work now. In this corrosive system, the main connections to the electrodes are very easily corroded and often lose contact. Clean the connections. If your power supply has a fuse, it may be blown. Is the cathode submerged in the solution? Do you have power? Are the parts really gold plated? Do you have the polarity right, (+) to anode and (-) to cathode?


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## lazersteve (Apr 15, 2007)

Paige,

Chris is right on the money. I would start with checking for corroded leads. Dip the large positive clip in some clean water and tap off the excess, clip it to a known gold plated part and dip the part into the bath. If it doesn't fizz try wetting the negative clip lead. Eliminate all unecessary leads and clips to verify the base components are functioning. Make sure you don't have any bad splices in your power leads circuit. The lead cathode can also become oxidized where the negative lead clips on. A volt meter can quickly verify that power is coming out of the charger.

Steve


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## dwt9999 (Apr 29, 2007)

I have been running two cells, next to each other so I can hopefully get through a large quantity of scrap prior to melting. I have not been able to get back to the cell as often as I would like(ie a day or two later). My refining is all done outdoors(due to my lack of a garage). I do cover the cell with plastic wrap and then cover with a bucket. 

I find that I am unable to process large qty(ie: more than 3/4lb) without the cell stalling or just stoping, I really don't think I have reached the capacity I should get to.

How much can usually be processed into 2 - 2 1/2 cups of acid?

I have resorted to empting and starting with a fresh batch of acid. Does the process usually slow that much?

I should tell you that I have been using a SS kitchen sink drain screen for the anodes, with a copper wire to hold it.

Perhaps I am in too big a hurry.

Any help would be greatly accepted!!

thanks in advance!

Lew

PS--Does anyone else 'boil' down the electrolyte instead of adding water to precipitate?

Please let me know!!


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## Harold_V (Apr 29, 2007)

Not having experienced these stripping cells, I may not fully understand what's happening, but I have read the original patent on the concept and understand the basic theory on how they work. One of the conditions of proper operation is high current density. Near the anode, the current density is great enough to dissolve the values, but sulfuric acid is unable to keep them in solution when they leave the proximity of the anode, so they should self precipitate. Considering the elements are removed an atom at a time, the precipitate is very fine (colloidal), which accounts for the black/purple color. 

A couple things come to mind. High current density is related to anode size. As the size of your charge increases, greater amperage must be available. Move to a variable voltage power supply that is capable of greater amperage than you have at your disposal and you may well see action where you now do not. As I recall, open circuit voltage should top out at 18 volts. You can raise your voltage that high before you would expect unwanted activity in the cell. When a cell that has been functioning quits, it's a sign of either a bad connection somewhere, or one of two other things, at least as I see it. One of them is the electrolyte is too low in specific gravity, or the power required is not adequate for the anode size. 

As I understand it, the cell quits working when all values have been stripped. The atoms of metal no longer are being carried by the electrolyte, which has an effect on its conductivity, with a resulting drop of amperage. 

If these ideas are correct, they may be helpful in troubleshooting your operation. If they are incorrect, I'd appreciate hearing from those of you that have experience in running stripping cells. I always welcome corrective information when it's dispensed without insults.  

Harold


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## goldsilverpro (Apr 29, 2007)

dwt9999,

Please explain what stalling or stopping means.

If you have too much gold in the solution, the amps won't go to zero when all the gold has stripped. It's been so long that I don't remember how the saturation of gold affected the stripping rate. Does your ammeter go to zero.

Try cleaning all of your connections. They corrode quite easily and lose contact.

The anode is the gold plated parts you are stripping. It is connected to the positive (+) lead. The other electrode, the screen I assume, is the cathode and is connected to the negative (-) lead. Is this how they are hooked up? Both are called electrodes.


Harold,

Please forgive me but I found out, in practice, that the system will strip no matter what voltage you use (almost). I always started the voltage at zero and slowly cranked it up. I was processing large loads and my 200 amp rectifier might nearly peg, at the start, with only 1 or 2 volts. Within maybe 30 seconds, the amps started decreasing and I would slowly crank up the volts to maintain maximum amps. After a few minutes, the voltage was about 6 or 8 and I could walk away safely without worrying about the amps banging the peg and blowing a fuse. I was stripping thick gold braze and, after about 15 minutes, the amps were at zero and the volts were pegged, at 12 volts. All gold was stripped. 

After running this thing for years, I have come to the conclusion that if, you have a controllable power supply, it makes no difference how large it is. The only difference is that a smaller power supply will be proportionally slower. Instead of 15 minutes for a 200 amp supply, a 20 amp supply might take 150 minutes. They are both 3000 amp-minutes. I don't think that Mason, who wrote the patent, had a very good feel for how this system works. He probably found something that worked for his narrow application, and Western Electric forced him into a quick patent.

Since I've been on the forum, I've always been against the use of these fixed power supplies. You are so limited by using them because, if you overload them, the power supply could burn out, if there's no fuse. Steve, correct me if I'm wrong about this. If you had a control, you could load the cell with as much stuff as you could squeeze into it. I know that controllable power supplies are much more expensive. On one thread, I suggested that you could plug these into a Variac. But, they're also expensive. On this same thread, Steve suggested another way.

http://goldrefiningforum.com/phpBB3/viewtopic.php?t=226&highlight=variac


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## lazersteve (Apr 29, 2007)

Lew,

For starters, I think you are probably overloading the charger. Does your charger have an ammeter on it ? The unit will protect if it is overloaded and after a short time the resettable thermal fuse inside will cool and reset itself. The unit will work again until overloaded again. Repeated overloads will destroy your charger. 

Secondly, using the screen setup for the anode has advantages and disadvantages. You already know the advantages so I'll skip them. The disadvantages are not readily obvious until you work with it more. Here's what I've found from using the screen in the past. 

1) It slowly dissolves into your electrolyte thereby inducing unwanted contaminants.
2) It partially shields the plated scrap from the current and therefore can slow the overall stripping time.
3) Not all the scrap placed on/in it will strip completely. This is due to the lack of current that passes thru the scrap. The screen in effect is robbing current from the scrap. With a finite amount of current at your disposal, you are losing a portion of it to the screen which extends the stripping time. 
4) Not all the scrap makes good contact with the screen and this slows the stripping as well.


As a test of the above statements pefrom the folllowing tests:

Place the basket *without* any scrap in it in the cell and observe the ammeter and cell reactions. You will notice the ammeter shows a small amount of current flowing with *no* gold in the basket. You will also notice a reaction in the cell with the screen. This should make it evident that the screen may be part of your problem and is inducing contamination as well.

On an up note, Harold has recently posted a suggestion to use a copper basket for the anode. I have yet to try it out, but I did some checking into the use of copper as the anode material and feel it holds promise as long as the electrolye is kept cool.

I hope this helps you find your problem, keep us posted.

Steve


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## goldsilverpro (Apr 29, 2007)

Steve,

What percentage sulfuric are you using for your cell? I assume you are using the same drain cleaner you started with. If I remember right it was fairly low, compared to some of the others out there. I know that the weaker it is, the more likely it will attack the nickel in the stainless screen (I assume the screen is non-magnetic). Nickel has always been the bad actor in this whole system.


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## lazersteve (Apr 29, 2007)

According to the bottle it contains 'concentrated' sulfuric acid. I don't have an MSDS so I can't say for sure. I've heated some for an extended period of time and it lost very little volume. I haven't checked it's specific gravity to date. 

Steve


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## dwt9999 (Apr 29, 2007)

When I mentioned the stalling or stopping, after I have processed about a pound and a half of plated pins then the aid reacts mor to the stainless steel than to the gold. I believe it has to do with the small 'fixed' source of power I am using. I do ensure the lead is cleaned periodically I actually keep a third rod and clean it and wait to put it into the next cell, kind of a rotation of the rods. 

I also keep checking for the continuity of the power, and I have even changed the aluminum foil when needed. Perhaps the ss screens I use get corroded and do not allow good current transfer. The Posts that were in response to the problem have given me a lot to look into and work on.

Thanks again!!

lew


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## lazersteve (Apr 29, 2007)

GSP,

I just found a source on the web that states Rooto Drain opener is 96-98%.


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## Harold_V (Apr 29, 2007)

goldsilverpro said:


> Harold,
> 
> Please forgive me but I found out, in practice, that the system will strip no matter what voltage you use (almost).



No need for forgiveness. I appreciate your input, particularly when it goes hand-in-hand with the laws of electricity as I understand them. 

Voltage is a function of anode/cathode spacing and conductivity of the solution. It won't be the same for every cell, so nothing you can tell me about the applied voltage would concern me---right down to a cell functioning on as little as a couple volts. It's all to do with Ohm's law. Amperage is the indicator of transfer in this case, not voltage. 

I think I'd have to agree with you that there was a bit of rush to judgment when the patent was filed, but one thing is clear. If you run voltage too high, you will have transfer of unwanted elements. Exceeding the 18 volts open circuit is, apparently, that threshold, which is why it was mentioned. In order to have control over how these cells function, it's very important to be able to control voltage. Otherwise you're stuck with what you get, right, or wrong. 

I had a negative experience once with my silver cell. There was some minor bridging of silver from the filter in the basket to one of the stainless screws that held the basket together. The screw was seriously degraded, and the batch contaminated. 

Nothing surprises me anymore when it comes to electrodepositing. 

Harold


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