# Silver Cell Tweaks



## rfd298 (Aug 2, 2010)

Here is the background:

I have tweaked Lazersteve's recipe a bit from his Silver Cell video. My cell consist of 3L of electrolyte, from which I used 9 oz of .999 Canadian Maple Leafs to create. The actual cell is a couple of Walmart mini plastic tubs (I two plied the tubs in case of failure). The basket is another plastic tub with holes drilled in the bottom to allow the fluid to flow. I placed 4 stainless steel studs in the basket to allow the basket to slide across the top so I can scrape. The basket is lined with a reusable Polypropylene shopping bag cut to fit. I am using Sterling as my silver formed into anodes of around 4-5 oz each. ( I also understand that Sterling will pollute my electrolyte quicker than a better grade of Ag). My cathode is a 3" x 1.5" x 1" piece of graphite. Amps normally start out around 6A but falls to 3.5-4 A when the graphite cathode gets covered with tiny silver crystals. My output is about 1/2 ounce per hour.

I am quite happy with the output, but can I tweak anything to get additional output. Bigger or smaller cathode? More or less voltage, or Amps? A larger or smaller Anode? Just curious. Is there a formula or something to help guestimate what the expected outputs of a cell of a certain size should be running at?

Thanks for your input,
Ken


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## goldsilverpro (Aug 2, 2010)

Your cell is closer to a traditional Thum cell than any I've seen anyone else build, which is good. To prevent the solution from getting too hot, 6 or 7 amps is about right for a 3 liter solution. I wouldn't push it much higher. The 30 gallon cells I ran produced about 20-25 oz/hour, depending mainly on the starting Ag purity. How much voltage are you using for the 6A? It should be about 3-4V? What sort of power supply are you using?

I would suggest that the cathode be about at least twice the anode surface area. I would also use 300 series stainless. I don't really care for the large stringy crystals - too easy to short out. I would shoot for a smaller, harder crystal. Why the blue mesh (it appears to be an open mesh?) bag? I would think that any undissolved material from the anodes would go through the bag and contaminate the crystal. Traditionally, a double layer of 100 thread count unbleached muslin is used. There are many other types of cloth that can be used, however. Generally, if you want more production, build a bigger cell.


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## rfd298 (Aug 6, 2010)

I have been pushing the voltage a little higher than the normal 3-4 volts to get the Amps up on this Power Supply. My power supply is a 0-30V / 0-10A Linear DC Power Supply.

The cloth is a mesh Polypropylene shopping bag but it is tighter than it appears in the picture. I was thinking of switching to two ply polyester shower curtain but I don't know how well it would handle the solution so I shall acquire some unbleached muslin. Like I said before I am pleased so far with the results. My next cell will be bigger. Thanks for your input.


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## Oz (Aug 7, 2010)

You are right that the amps are what does the work if you wish to increase production, but I would not push them by increasing your voltage. You defeat the purpose of the cell doing so as it will affect your final purity. 

As to your anode basket, I use muslin from Walmart as it is cheap and effective. Further you need to consider the processing of your slimes if you plan on doing more than sterling a few times. The muslin burns even half wet due to the nitrates with little ash, try that with polypropylene.

I am curious as to your anode to cathode gap seeing your thready crystals. They are a short and hole waiting to happen in your anode basket. If all other parameters are in balance in your cell thready crystals are also indicative of a contaminated solution. In this case though it is probably due to over voltage based on your comments. 

Both GSP and Harold have helped me greatly in my learning curve.


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## lazersteve (Aug 7, 2010)

Oz said:


> ... The muslin burns even half wet due to the nitrates with little ash, try that with polypropylene.



I use a polypropylene cloth that is completely resistant to AR and is cleaned by boiling in AR. I can then re-use the cloth.

Steve


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## Oz (Aug 7, 2010)

I had not considered having washable basket cloth. That should be fine with AR as long as you are not having any rhodium in your silver anodes.


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## Lou (Aug 8, 2010)

Polypropylene is pretty chemical resistant. Polyester of any sort is NOT. 

Keep polyester, polyamides, and any other condensation-type polymers out of acidic or basic environments.


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## 4metals (Aug 9, 2010)

I've been sending clients to this guy for anode bags http://www.anodeproducts.com/anodebags.html
His prices are good, he makes any size custom, and the orders don't have to be terribly large either.


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## bmgold2 (Mar 4, 2014)

Has anyone ever used Tyvek as a silver cell anode bag? Just in case anyone doesn't know what Tyvek is, it is used for house wrap, disposable coveralls, and those envelopes you get sometimes that can't be ripped.

I haven't done any experimenting but one site I found online talked about using Tyvek in a divided cell. The only problem I can see (if it works) is if the electrolyte gets hot it might melt. That particular property of this stuff might be useful to make the bag though instead of sewing it.

EDIT: here's a link about this product.

http://www2.dupont.com/Tyvek/en_US/products/product_properties.html

OUTSTANDING CHEMICAL RESISTANCE
Spunbonded Olefin is inert to most acids, bases and salts. Prolonged exposure to oxidizing substances, such as concentrated nitric acid or sodium persulfate, will cause some loss of strength.

I think I may have found the problem with this material:

http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=50&t=16132#p163199



goldsilverpro said:


> Also, if the mesh of the cloth you use for the anode bag is too tight, it can hinder solution flow (but not current flow) and will soon deplete the solution of silver. You can't just use any type of cloth.



The Tyvek would probably not only hinder solution flow but basically prevent it.


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## sharkhook (Mar 4, 2014)

If you want to try it, I still have a pair or two of the coveralls. I had to wear those things 12 hours a day, 7 days a week during the oil spill in the gulf. They are hot, but some air does get through them, only slightly though. Come to think of it they make a great rain suit as they keep water out, might be to tightly woven.


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## bmgold2 (Mar 5, 2014)

sharkhook said:


> If you want to try it, I still have a pair or two of the coveralls. I had to wear those things 12 hours a day, 7 days a week during the oil spill in the gulf. They are hot, but some air does get through them, only slightly though. Come to think of it they make a great rain suit as they keep water out, might be to tightly woven.



Well, I tried a quick experiment to see if the Tyvek might work. I took some salt water in a plastic container and then put the Tyvek bag in the water. I then added some of the salt water to the bag since it is water proof and no liquid got in or out of that bag. I put an electrode in each section (inside and outside the bag) and hooked it to the power supply.

No reaction at all. I moved the outer electrode inside the bag and got an instant chlorine smell and lots of bubbling. Next, I decided maybe it just needed more power so I found a 12 volt battery and hooked that up in series with the power supply. Still no reaction.

Then I accidentally shorted the power supply to the battery and ruined my fancy power supply. Now I'll have to rig up a computer power supply or car battery charger if I need to run my stripping cell.

Oh well, I gotta learn things the hard way. Now I know that Tyvek won't work for a silver cell and my power supply didn't have a fuse to protect it from my mistakes.


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## Palladium (Mar 5, 2014)

Didn't you say you were using a Mastech power supply? If that's the case the cutout relay tends to stick when it shorts out if it's an older model. Try turning it off and slapping the top with the palm of your hand kind of hard and then turn it back on. Sometimes it takes one or two times. They have corrected that problem now.


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## bmgold2 (Mar 5, 2014)

Palladium said:


> Didn't you say you were using a Mastech power supply? If that's the case the cutout relay tends to stick when it shorts out if it's an older model. Try turning it off and slapping the top with the palm of your hand kind of hard and then turn it back on. Sometimes it takes one or two times. They have corrected that problem now.



No, it was a Hy elec model HY1503D power supply. I opened it up and looked to see if anything was visibly blown out and didn't find anything. I tapped on the relay several times and that didn't help. The meters still work but the current never goes completely to zero any more and the voltage control doesn't change anything.

What I did was feed power back into the power supply from the battery so I blew something out. I emailed the company to see if I could get a schematic but don't expect a reply. It wasn't a real expensive power supply so I don't think sending it out to be repaired will be an option even if it was offered. It won't matter that much for the gold stripping cell but the silver cell I wanted to build someday will be tougher now. Good thing this was just a hobby and not how I was making money.

I'm going to try the computer power supply next time I want to strip some parts.


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## bmgold2 (Mar 13, 2014)

I tried my computer power supply with my Micro stripping cell and it works great. According to the sticker on the power supply, it should have a brown wire to supply 3.3 volts. I checked every wire that came out of the box and there is no brown wire and testing the wires with a voltmeter shows that none of them provides the 3.3 volts I would need to run a silver cell. I guess I'll have to find another power supply if I ever build a silver cell.

I did make up a pattern to cut out a tiny cell basket to use in the same type of glass candle holder that I used on my Micro stripping cell. The assembled basket shown is just stapled paper to test the size. I'm not sure if the seams should be inside or outside the bag. Probably doesn't matter if you plan to burn it when done to recover any values it contains.




Keep in mind that I am still in the experimenting mode so all of my refining so far has been very small scale. I don't have a good, warm place to do the refining yet and don't have a lot of material to process. Now I'm trying to decide on a material for this tiny bag. I could just wait until I make it to a fabric store and buy a yard of muslin cloth or get a vacuum cleaner bag but I'd like to use something I already have (FREE) if possible. Would regular cotton cloth, like an old sheet or pillow case, work for the bag? What about a couple coffee filters sewed up? Remember, this is just a tiny scale test and I'm only hoping to refine a few ounces or so of silver in it. I still don't have the good nitric acid either and don't know if I will eventually buy a little bit of it or figure out how to distil my own. Buying it pre-made would be faster and safer but if I could make my own, I should be able to make it whenever I need some fairly cheap once I was set up. Right now, I just want to get the cell figured out and worry about the electrolyte latter.


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