# Silver Cell details



## Junkman Jim

Here are some pictures of my silver cell. I constructed it with a container I bought at Walmart, the container is 7"x7"x7". I drilled holes to accept stainless steel rods to suspend the polyester canvas bag, cathode, and anode. The spacing between the cathode and anode is about 3".
The electrolyte is 68% nitric acid saturated with 20 or so ounces of silver. I'm using 1.25 volts measured at the cathode and anode bars. The source is 3 10 to 12 ounce bars of silver and that is plated onto 3 strips of stainless steel 1" x 4", .030" thick. The attached cell pictures are after about 6 hours of plating, the long crystals grow after about 10 hours or so. (see additional pics.)


----------



## Noxx

Very nice ! I love the crystals shape.


----------



## Anonymous

how many amps is you cell running? Nice by the way. Were did you get a power supply at that voltage? Sorry for asking so much but I can see were your dissign could be useful to me.

Jim


----------



## Junkman Jim

I'm not sure how much current the cell takes. The supply is capable of about 80 amps at 0 to 5 volts. I built the supply myself to include the transformer.
I started with a transformer capable of a couple hundred watts, I removed the secondary and replaced it with 8 turns of No. 8 insulated wire with a center tap. I put a 2.5 amp variable tranaformer on the input of the stepdown transformer.
One day when I find some spare time I'm going to hook up an ammeter as I'm also curious how much current this thing draws. The supply doesn't even get warm , I'm guessing it only draws around 10 amps.


----------



## Anonymous

Looks real nice, did you build the diode bridge also? I have diodes from microwaves and think they should be ok.

The transformers I have are 2000 watts so I know that I can get the power, I was also thinking of several taps for different voltages. I have already taken the old secondary out because I made a small spot welder with it.

Jim


----------



## Shecker

A very nice little system. If you were using impure silver Dore that contain gold, pgm as your starting put, the precious metals other than silver would remain behind in the bag. Only palladium, if present, would build up in the electrolyte.

Randy in Gunnison


----------



## goldsilverpro

Very nice, Jim. About 1 gallon. Twenty oz of Ag/gal. Seems like the parameters you've chosen have solved the problem of producing large crystals. How large is the crystal in the 2nd photo?

How did the Copper get into the cell? Did you add it intentionally or did you use sterling as a source of silver? If you added it intentionally, how much did you add?

You can get a close approximation of the amperage by weighing the silver output over a period of time. One amp for one hour (an amp-hour) will produce about 4.02 grams of silver, at 100% cathode efficiency. The actual efficiency should be about 96-99%.


----------



## Anonymous

GSP, is it amperage only that matters when comparing the amount of silver deposited or will higher voltage have an effect?


----------



## Junkman Jim

james122964 said:


> Looks real nice, did you build the diode bridge also? I have diodes from microwaves and think they should be ok.
> 
> The transformers I have are 2000 watts so I know that I can get the power, I was also thinking of several taps for different voltages. I have already taken the old secondary out because I made a small spot welder with it.
> 
> Jim


The power supply is full wave, one 40 amp diode on either side of the center tap. You can see the studs of the diodes sticking out the back of the supply (lower left of picture). Generally the larger the tramsformer the fewer volts per turn. You may only need a couple turns to get the necessary voltage. I thought about taps but a variable transformer is so much more convenient, this supply goes from zero to five volts. I can do copper at .3 volts, silver at 1.25, or silver strip at 4 volts. Alternator diodes should work fine.


----------



## Junkman Jim

goldsilverpro said:


> Very nice, Jim. About 1 gallon. Twenty oz of Ag/gal. Seems like the parameters you've chosen have solved the problem of producing large crystals. How large is the crystal in the 2nd photo?
> 
> How did the Copper get into the cell? Did you add it intentionally or did you use sterling as a source of silver? If you added it intentionally, how much did you add?
> 
> You can get a close approximation of the amperage by weighing the silver output over a period of time. One amp for one hour (an amp-hour) will produce about 4.02 grams of silver, at 100% cathode efficiency. The actual efficiency should be about 96-99%.



The large crystal is just over an inch.
I used silver salvaged from tanalum capacitors for my electrolyte, the green color of the electrolyte is probably iron as there was a steel washer in each capacitor. The electrolyte also contains some tin, lead, and a little bit of copper. The electrolyte in the cell in the picture has produced 120 troy ounces of silver.


----------



## Junkman Jim

james122964 said:


> GSP, is it amperage only that matters when comparing the amount of silver deposited or will higher voltage have an effect?



If you increase the voltage other metals will plate and contaminate your silver


----------



## goldsilverpro

Are you talking about the electrolytic tantalum/silver capacitors with the red or green plastic plug on one end? If I remember right, the red ones ran 40% silver and the green ones ran 25%.

Do you have proof that increased voltage affects the purity? If so, how did you determine that? The standard cell runs at 3V and produces 999.9 silver. The anode current density is about 50 amps/sq.ft. Only certain specific impurities, such as Pd or Cd, cause problems. Of course, large quantities of any metal will cause purity problems. The limit on copper is about 12 oz.gal. Of course, the main purpose of a standard cell is to produce pure silver and not to produce pretty crystals.

Do you know the total running time to produce the 120 oz?


----------



## Junkman Jim

goldsilverpro said:


> Are you talking about the electrolytic tantalum/silver capacitors with the red or green plastic plug on one end? If I remember right, the red ones ran 40% silver and the green ones ran 25%.
> 
> Do you have proof that increased voltage affects the purity? If so, how did you determine that? The standard cell runs at 3V and produces 999.9 silver. The anode current density is about 50 amps/sq.ft. Only certain specific impurities, such as Pd or Cd, cause problems. Of course, large quantities of any metal will cause purity problems. The limit on copper is about 12 oz.gal. Of course, the main purpose of a standard cell is to produce pure silver and not to produce pretty crystals.
> 
> Do you know the total running time to produce the 120 oz?



GSP,
These capacitors are 3/8" in diameter and about 3/4" long and have a slug of solid tantalum immersed in potassium hydroxide. There's a steel washer with a green or red glass insert surrounding the kovar lead that connects to the tantalum slug. The washer is soldered to the case which is almost pure solid silver. It only takes 15 or 16 cases to make a Troy ounce of silver.

I was told by a 74 year old friend who's lifetime livelyhood has been recovering precious metals that increased voltage will plate other metals which seems reasonable since different metals require different voltages.
Oh, by the way try to find those voltages on the web or even in Hoke's book. Since you mentioned it, I might try the higher voltage although I'm getting tremendous results at 1.25 volts.

I haven't kept track of the precise time but the cell produces 6 to 12 Troy ounces in a 24 hour period.

One problem I have is connectivity, I drill my silver bars then screw a stainless steel hook into them and hang them on a stainless steel bar. I need a better way of making that connection, I've tryed other metals, you just can't keep the corrosion away.


----------



## scrapman1077

could you post a pic of the capacitors? Thanks


----------



## Anonymous

If you bent your anode hooks a little different you could use split bolts to 
hold them down and get better conductivity. Also, maybe a conductive grease.

or instead of round bars use square and hold with clamps for better conductivity.


----------



## Anonymous

So the large transformer is stepping down the smaller variable transformer or are you using the output from the variable transformer to choke the larger one?


----------



## Junkman Jim

scrapman1077 said:


> could you post a pic of the capacitors? Thanks



Scrapman,
Here's a couple pics of the solid tantalum caps to look for, the two on the left have solid silver cases (worth more than a buck apiece), the next one is silver plated brass (worth much less), the two on the right are solder plated brass (only worth the value of the tantalum), and the case on the one in front is solid tantalum.
I tryed to find the price of scrap tantalum, as near as I can tell it'a somewhere around $45.00 per pound.


----------



## Junkman Jim

james122964 said:


> So the large transformer is stepping down the smaller variable transformer or are you using the output from the variable transformer to choke the larger one?



Jim,
Put the variable transformer on the primary of the step down transformer.
If the step down transformer is capable of 200 watts output that means the input is 200 watts. If you want 0 to 5 volts wind the secondary for 5 volts, the variable transformer will then take the input of the step down from 0 to 120 volts taking the secondary from 0 to 5 volts. 200 watts at 5 volts is 40 amps. Be sure the wire you use is capable of 40 amps, I used two windings of No. 8 copper.
Hope this helps.
Thanks for the ideas on the anode hooks,
Jim


----------



## goldsilverpro

Try this. Grind the hooks so they form a knife edge where they make contact to the bar.


----------



## Anonymous

GSP I think that is an excellent idea.


----------



## scrapman1077

Junkman Jim, Thanks for the pics.


----------



## Anonymous

is the tantalum a solid chunk inside the capacitor? do you know were to sell the tantalum?

thanks.


----------



## Junkman Jim

james122964 said:


> is the tantalum a solid chunk inside the capacitor? do you know were to sell the tantalum?
> 
> thanks.



Jim,
Yes it is a solid chunk, the size varies with the value and voltage of the capacitor. I did a bit of research on the web but could not find anybody that was buying it. One site said if was worth $100.00 per kilogram. Tantalum is heavy, 16.69 sp. gr. and melts at a very high temp 5463 degrees fahrenheit. If you find a buyer let me know.
Thanks,
Jim


----------



## Lou

I know of a buyer. Here's their number: 1-779-297-6591

Other people: http://www.centauruk.co.uk/tantalum.html

Pure tantalum is worth much more than $100/kg. Also be on the look out for hafnium too (min. 300/kg).


----------



## Junkman Jim

Lou said:


> I know of a buyer. Here's their number: 1-779-297-6591
> 
> Other people: http://www.centauruk.co.uk/tantalum.html
> 
> Pure tantalum is worth much more than $100/kg. Also be on the look out for hafnium too (min. 300/kg).



Thanks for the lead Lou, speaking about hafnium, I have a small amount, just less than an ounce. How do I melt it without it oxidizing and bubbling? It may not be quite pure but at the temperature that it melts everything else should have vaporized.


----------



## Junkman Jim

Lou said:


> I know of a buyer. Here's their number: 1-779-297-6591
> 
> Other people: http://www.centauruk.co.uk/tantalum.html
> 
> Pure tantalum is worth much more than $100/kg. Also be on the look out for hafnium too (min. 300/kg).



Lou,
I tryed that number, I can't get through, they want a remote personal ID number. Any ideas?
Jim


----------



## Lou

Beats me really, I just had the number in my rolodex with "tantalum buyer". Albeit the number could be very old. 

The other people were recommended by a friend.

As for melting hafnium...you don't. It's very, very hard to melt, and it will form a durable oxide long before that. Only way you'll be melting it and keeping it pristine is in an inert atmosphere via arc or ebeam melting. Maybe induction might work.


----------



## Anonymous

Your transformer must be larger than it appears. I cut the secondary out of one today 70va and tried to wrap with #12, I could only get 5 wraps in the space and .345 volts so I went down to #18 and managed to get .876 volts. The primary amp draw was only .01 amp.

Can you tell me the VA rating of your transformer, please :wink:


----------



## Junkman Jim

james122964 said:


> Your transformer must be larger than it appears. I cut the secondary out of one today 70va and tried to wrap with #12, I could only get 5 wraps in the space and .345 volts so I went down to #18 and managed to get .876 volts. The primary amp draw was only .01 amp.
> 
> Can you tell me the VA rating of your transformer, please :wink:



Yes it is bigger, I believe it's about 200 VA, it's about 4 inches on all sides. Be careful, the current carrying capacity of No. 12 in a transformer is only about 9 amps, if you build a full wave rectifier with two diodes, one on each side of a center tap that figure doubles.
Looks like your transformer delivers .07 volts per turn, larger transformers deliver more voltage per turn. The secondary on my transformer is only 4 turns on each side of the tap, that means about 1.25 volts per turn. The wire of choice for a transformer would be enameled copper, I didn't have any No. 8 enameled so I went with insulated stranded. Insulated stranded wire is much easier to work with, it's much more flexible and enameled wire is susecptable to scuffing increasing the chance of a short. You could put several secondaries hooked in parallel to obtain the desired current. Be sure all have the same number of windings.
Hope this helps,
Jim


----------



## netseeker

I know a buyer for Ta scrap. Exotech, Inc in Pompano Beach, Fl. buys Tantalum and other rare metals including Hafnium. Been doing business with them for several years. David Gussack is my contact. Their phone # is 954-917-1919. They also also have a web site. They have always done well by me and I've sent them a LOT of scrap so they've gained my trust. David is always interested in buying scrap.


----------



## Junkman Jim

netseeker said:


> I know a buyer for Ta scrap. Exotech, Inc in Pompano Beach, Fl. buys Tantalum and other rare metals including Hafnium. Been doing business with them for several years. David Gussack is my contact. Their phone # is 954-917-1919. They also also have a web site. They have always done well by me and I've sent them a LOT of scrap so they've gained my trust. David is always interested in buying scrap.



Thanks for thr lead, he wants Ta by the ton.
Jim


----------



## Anonymous

Junkman Jim said:


> scrapman1077 said:
> 
> 
> 
> could you post a pic of the capacitors? Thanks
> 
> 
> 
> 
> Scrapman,
> Here's a couple pics of the solid tantalum caps to look for, the two on the left have solid silver cases (worth more than a buck apiece), the next one is silver plated brass (worth much less), the two on the right are solder plated brass (only worth the value of the tantalum), and the case on the one in front is solid tantalum.
> I tryed to find the price of scrap tantalum, as near as I can tell it'a somewhere around $45.00 per pound.
Click to expand...


Hi, I am total n00b to this stuff so please bear with me if I ask dumb things!
Where would one look for these types of caps?

Thanks!


----------



## Junkman Jim

BCBUD said:


> Junkman Jim said:
> 
> 
> 
> 
> 
> scrapman1077 said:
> 
> 
> 
> could you post a pic of the capacitors? Thanks
> 
> 
> 
> 
> Scrapman,
> Here's a couple pics of the solid tantalum caps to look for, the two on the left have solid silver cases (worth more than a buck apiece), the next one is silver plated brass (worth much less), the two on the right are solder plated brass (only worth the value of the tantalum), and the case on the one in front is solid tantalum.
> I tryed to find the price of scrap tantalum, as near as I can tell it'a somewhere around $45.00 per pound.
> 
> Click to expand...
> 
> 
> Hi, I am total n00b to this stuff so please bear with me if I ask dumb things!
> Where would one look for these types of caps?
> 
> Thanks!
Click to expand...


These capacitors were made in the 1960s and 1970s and since replaced by solid tantalum caps dipped in plastic (orange drop). Look for old surplus military or FAA equipment.


----------



## usaman65

I would try ebay on the hafnium .......

kev


----------



## Anonymous

Could you elaborate a little more on your design? This might work for something I am working on.


----------



## Refiner232121

Question 1.
would it not be enough to buy a battery charger like this one
http://cgi.ebay.ca/Deltran-Battery-Tender-12-Volt-1-25-Amp-2-Bank-Charger_W0QQitemZ130312741769QQcmdZViewItemQQptZMotors_Car_Truck_Parts_Accessories?hash=item1e573ea389&_trksid=p3286.c0.m14&_trkparms=65%3A12|66%3A2|39%3A1|72%3A1215|293%3A1|294%3A50

and connect it to the anode and the cathode


Question 2.
What kind of a metal it the cathode

Also 
I cant understand what these terms are doing in this subject
capacitors,transformer,diode, tantalum, hafnium


----------



## Junkman Jim

Refiner232121 said:


> Question 1.
> would it not be enough to buy a battery charger like this one
> http://cgi.ebay.ca/Deltran-Battery-Tender-12-Volt-1-25-Amp-2-Bank-Charger_W0QQitemZ130312741769QQcmdZViewItemQQptZMotors_Car_Truck_Parts_Accessories?hash=item1e573ea389&_trksid=p3286.c0.m14&_trkparms=65%3A12|66%3A2|39%3A1|72%3A1215|293%3A1|294%3A50
> 
> and connect it to the anode and the cathode
> 
> Answer 1. Too much voltage, not enough amperage. It only takes just over one volt to plate silver. The power supply that I built varies from zero to five volts at about 80 amps.
> 
> Question 2.
> What kind of a metal it the cathode
> 
> Answer 2. Stainless steel.
> Also
> I cant understand what these terms are doing in this subject
> capacitors,transformer,diode, tantalum, hafnium



The tantalum capacitors are where I obtained the silver. The transformer and diodes are part of the power supply.
Regards,
Junkman Jim


----------



## Refiner232121

Hi Jim
Thanks for your reply I really appreciate that.
I guess I can buy one of these contraptions from Ishor or an jewelry tool suppliers
Thanks again


----------



## Refiner232121

Hi Jim
1 other thing
I am not sure about this
The unrefined silver that's hanging in the cell looks like when the silver was in an molten state you placed a peace
of steel that's has a hook shape. 
Is this correct or did you do something else
Thanks


----------



## Junkman Jim

Refiner232121 said:


> Hi Jim
> 1 other thing
> I am not sure about this
> The unrefined silver that's hanging in the cell looks like when the silver was in an molten state you placed a peace
> of steel that's has a hook shape.
> Is this correct or did you do something else
> Thanks



I poured the bars then drilled a hole in the end. I then screwed the stainless steel hooks into the bars. The hooks can easily be made from a one eighth inch stainless steel welding rod. Keep the rods out of the electrolyte, they will desolve into the solution.


----------



## Refiner232121

Hi JIm 
Thanks for your explanation.
I will have more questions later on but for now I am ok
Thanks


----------



## Refiner232121

Hi Jim 
I wanted to know if you tried to refine in this cell with using other chemicals instead of nitric acid
Thanks


----------



## goldsilverpro

With this cell, I think you're stuck with using nitric acid.


----------



## Junkman Jim

Refiner232121 said:


> Hi Jim
> I wanted to know if you tried to refine in this cell with using other chemicals instead of nitric acid
> Thanks



Nitric acid is the best solvent for silver, I don't believe there's anything that would work better.
Junkman Jim


----------



## Refiner232121

These are for plating
Can I use one of these rectifiers for this process



> DPS-5012M 60 Amp- Runs plating baths up to 20 gallon (except rhodium, which is less). Also suitable for stripping and refining.



Can I make do with something cheaper than having to spend $800 dollars

Thank You


http://ishor.com/Rectifiers.htm


----------



## goldsilverpro

The 25 amp rectifier will produce up to 100 grams (3.2 tr.oz.) of silver per hour at about 3 volts. The efficiency is mainly dependent upon the purity of the anodes. For example, running 99% silver is much more efficient than 90% silver, for several reasons. Since it is a 12 volt rectifier, 3 or 4 nearly identical (same size, shape, solution composition, anode size, etc.) cells can be run together in series to increase the silver output 3 or 4 times.


----------



## Harold_V

goldsilverpro said:


> cells can be run together in series to increase the silver output 3 or 4 times.


I assume your comment of running more than one cell in "series" is to imply that they are run in tandem. Series wiring of cells would require a higher operating voltage. In order for the cells to capitalize on the amperage with the same voltage, they would be wired parallel. 
Still operating in tandem, but wired differently. Did I miss this one?

Harold


----------



## goldsilverpro

Harold, I also have to think about which way it is rigged every time I talk about it.

Series.

Amperage is constant and Voltage is additive in a series circuit. You have a 25A, 12V rectifier. You pull about 25 amps @ 3volts for a 3 gallon cell, using about 0.4 sq.ft. of anode area, standard solution composition, and 4.5" anode/cathode spacing. At 100% efficiency, using these parameters, one cell produces about 3.2 tr.oz. of silver/hour. With 4 identical cells of this size, you would apply 25 amps (Amperage is constant) in *EACH* cell @ 3 volts, for a total silver output of 12.8 tr.oz./hour. You would have a total of 12 volts (4 cells x 3 volts, Voltage is additive) in the system. If the 4 cells weren't identical (actually, in practice, they will never be exactly the same), each cell would have a different amount of resistance and their individual outputs would be somewhat different, although the total output of 12.8 tr.oz./hour should be the same, as long as you applied 25 amps and a total of 12 volts to the whole system.

I have assumed 100% efficiency in these calculations. In practice, this will never hold true, especially when running silver anodes of less than about 98-99% purity.

In parallel, the total 25 amps would be divided among the 4 cells and you would only produce 1/4 as much silver as you would had they been in series.


----------



## Refiner232121

Hi Folks
I made an imaginary photo
I am not sure if I did it right


----------



## qst42know

That's a parallel circuit the voltage would be the same in each.


----------



## goldsilverpro

qst42know is right. You have it in parallel.

For series:

It goes (+)~+-~+-~+-~(-) The power supply terminals are in parentheses. The 3 +- pairs are the 3 cells. The ~ symbol represents cables.

The (+) lead from the rectifier is attached to the anode in the 1st cell. 
The cathode in the 1st cell is attached to the anode in the 2nd cell. 
The cathode in the 2nd cell is attached to the anode in the 3rd cell.
The (-) lead from the rectifier is attached to the cathode in the 3rd cell.

Try to make the cables the same length and gauge to help balance the resistance.

Believe it or not, it really does work.


----------



## Harold_V

Refiner232121 said:


> Hi Folks
> I made an imaginary photo
> I am not sure if I did it right


That would be correct if you had a power supply that had limited voltage, but ample amperage. In theory, if you wire the cells in series, each cell would require an increase in voltage of approximately 3 volts, assuming that was the correct operating voltage of the individual cells. You clearly would be limited to the number of cells that could be included, not only by amperage, but by voltage, assuming you had a limited voltage power supply. 

In reality, wiring as you indicated is fine. With a fixed voltage, the amperage will increase with each cell added, up to the capacity of your power supply, and it won't have a significant effect on the voltage (which would likely be near the open circuit voltage). Given the need, and I was to operate more than one cell, that's the way I'd wire them. It has specific advantages. One of them is the ability to disconnect one of the cells for maintenance without stopping all of them. Personally, I'd avoid series wiring for that reason, if no other. One of the other advantages of parallel wiring is the overall reduction of resistance. 

Harold


----------



## Refiner232121

Hi Folks
Thanks very much I really appreciate this


----------



## g_axelsson

goldsilverpro said:


> Try to make the cables the same length and gauge to help balance the resistance.



You don't need to have the same length on the cables. It is a series circuit and the voltage drop will happen outside of the cells. The voltage over each cell is only depending on the total current and the cell conditions, not the individual cable resistances.
Shorter cables would minimize resistive losses in the cables and give higher voltages over the cells.

/Göran


----------



## golddie

Hi Everyone

I am trying to build to power supply box for this project

I don't know electronics and it is becoming a big task
If I cant build this then I will have to buy it from a jewelery supply business
Before I buy a rectifier I want to try to build this myself
So I wrote to this company
http://www.addison-electronique.com/

This is what I asked them

--------------------------------
Hi 
I would like to make a cell like this one 
Can you tell me how much a power supply will cost
Here are some details
***********************************************************1.25 volts measured at the cathode and anode bars
capable of 80 amps but 
I'm guessing it only draws around *******************************************10 amps
-------------------------------
This is what they said to me

We carry a lot of parts that can be used for building power supplies. I can only guess from the copper sulfate bath in 
the picture that you want a power supply to feed the anodisation reaction. The tricky part about those supplies is that 
they are current-regulated supplies since the load is pretty much a dead short. Such power supplies are quite expensive 
and can be found in specialized metal working shops. The only option that we have here are variable voltage sources like 
this one :


https://www.addison-electronique.com/catalog/product_info.php?cPath=16_16003&products_id=203075&osCsid=ce4cc9eef1
ddda120bf7b026e52b7b47



The only thing missing is current-regulation, which can be homebrewed by using a pass transistor working in saturation 

mode (and picking a transisitor with the wanted curr

Thanks


----------



## Junkman Jim

golddie said:


> Hi Everyone
> 
> I am trying to build to power supply box for this project
> 
> I don't know electronics and it is becoming a big task
> If I cant build this then I will have to buy it from a jewelery supply business
> Before I buy a rectifier I want to try to build this myself
> So I wrote to this company
> http://www.addison-electronique.com/
> 
> This is what I asked them
> 
> --------------------------------
> Hi
> I would like to make a cell like this one
> Can you tell me how much a power supply will cost
> Here are some details
> ***********************************************************1.25 volts measured at the cathode and anode bars
> capable of 80 amps but
> I'm guessing it only draws around *******************************************10 amps
> -------------------------------
> This is what they said to me
> 
> We carry a lot of parts that can be used for building power supplies. I can only guess from the copper sulfate bath in
> the picture that you want a power supply to feed the anodisation reaction. The tricky part about those supplies is that
> they are current-regulated supplies since the load is pretty much a dead short. Such power supplies are quite expensive
> and can be found in specialized metal working shops. The only option that we have here are variable voltage sources like
> this one :
> 
> 
> https://www.addison-electronique.com/catalog/product_info.php?cPath=16_16003&products_id=203075&osCsid=ce4cc9eef1
> ddda120bf7b026e52b7b47
> 
> 
> 
> The only thing missing is current-regulation, which can be homebrewed by using a pass transistor working in saturation
> 
> mode (and picking a transisitor with the wanted curr
> 
> Thanks



If you look at the previous posts there are some instructions on how to build the power supply. I built the supply with used parts so it cost me very little. If you have a surplus electronics store close they would have everything you need and could probably help with the design. You could monitor the voltage with a cheap handheld multi-meter from Harbor Freight. I could draw a schematic and post it if that would help.
I did not use current regulation, instead I used variable voltage (0 to 5 volts) and allowed the cell to draw as much current as it needed.
Hope this helps,
Junkman Jim


----------



## golddie

Hi Jim
Thank you for taking the time to reply
Like I said when it comes to electronics I am a dummy
Its not something I am proud about
But you cant have everything
I went to Harbor Freight
I found this page
http://search.harborfreight.com/cpisearch/web/search.do?keyword=multi+meter&Submit=Go
If you can draw a schematic 
That would be real nice
I am thinking about making a few cells maybe 4 of them
I don't know if it will make business sense but that's another story
Thanks very much


----------



## Junkman Jim

It will take a little time to draw the schematic, I'll post it as soon as I can.
The $4.99 meter is just fine, they sometimes have that meter on sale for $2.99. 
I'm in Falcon, Colorado, if you're close you could stop by and see my supply.
My recomendation would be to increase the size of a single cell instead of using multiple cells as the electrolyte is very expensive. You might try several rows of anodes and cathodes alternately. My cell was less than a gallon of electrolyte and contained 20 troy ounces of silver.
My supply is more than capable to run four rows of anodes and cathodes.
Regards,
Junkman Jim


----------



## golddie

Hi Jim
Thanks for your reply.
It would have been nice if I lived in those parts but I am really too far away from there.
I live in Canada
I bet it must be beautiful in those parts.
I love birds do you get to see Falcons ,we have Falcons over here.
I like to watch birds and I am amazed at their intelligence.
By looking at your drawing I am not able to figure out what to do.
It seems like a simple project but when a person has not done any electronic project before it becomes 
like a big mystery
I will wait for you to draw the schematic
Thanks very much


----------



## Platdigger

Golddie, that is a schematic.


----------



## golddie

Hi Platdigger 
Now what do I do
I need a simpler schematic


----------



## Platdigger

What part of Canada are you in?
I have a bunch of power suplies, should be something that would work.
How big are you trying to go?


----------



## golddie

Hi Platdigger
Thanks for your reply
Something like Jims project or maybe 2 times the size of that


----------



## Platdigger

Having said that, and thinking about it further, most of mine go no lower than 5 volts.
I am not sure if just limiting the input voltage on these types of power suplies will work either.
But, if so, like I said, there are several.
There is an adjustment to the 5 volt output. I just don't know how low one can go with this.


----------



## golddie

Hi Platdigger 
I tried to send you a personal message but it did not work
I wanted to ask you for pictures of these items and how much
Thanks


----------



## qst42know

Hello Junkman.

What function does the capacitor serve?


----------



## AKDan

It is a smoothing capacitor. It's purpose is to remove as much of the AC component from the wave form as possible so that there is little fluctuation in the voltage of the output. Often there is more than just the one in a circuit when the current draw is high. A bridge rectifier would be better than the full wave in this circuit, and the DC output should also be regulated to keep things as constant as possible. This circuit will work, but there are better ways to do it I am thinking.


----------



## Junkman Jim

AKDan,
I chose this full wave rectifier so I could draw 40 amps from each side of the center tap. A bridge rectifier would eliminate the center tap, double the voltage, but cut the current in half. I wound the transformer spacifically for 5 volts at about 80 amps. If I would have used a bridge I would need two windings of No. 8 wire in parallel, there wasn't enough room on the transformer. The bridge offers a smoother output but in this application a smoother output is not essential. If I needed a smoother DC output (less ripple) I would increase the capacitance. With the Variac on the input of the step down transformer this supply is very precise from 0 to 5 volts. By the way in the past this is the way the big boys designed plating power supplies.
Regards,
Junkman Jim


----------



## AKDan

I can't disagree with anything you say in your response, and was not throwing down on the circuit that you had provided. I can say without reservation that it will work. However, I personally would prefer and probably add better regulation, and more smoothing. I do like the regulation on the primary side.

I really just started to answer as to the capacitor question and got a little carried away in thinking about what I remembered seeing. At least you stepped up and provided a circuit that will work, and is simple enough for the average person to throw together. For that you are applauded.


----------



## qst42know

I was just reading the wiki on bridge rectifiers and they have the capacitor included. They did mention the benefits of a bleed resistor for this capacitor to avoid unwanted surprises. :shock:


----------



## Junkman Jim

qst,
I do have a bleed resistor in my power supply, I just didn't put it on the schematic for simplification. The bleed resistor goes across the capacitor and takes it to zero volts very shortly after the power switch is turned off preventing unwanted voltage at the output of the supply. The bleed resistor is even more important on higher voltage power supplies where the potential for electrical shock is present.
Junkman Jim


----------



## aflacglobal

This may be a bit off topic here, but could a person use a car alternator to power a plating cell or something like that. Output is about 200 amp @ 13v. I've made generators using a 120 v a.c. motor mounted on a board with a belt to an alternator to power it. It's not the most efficient way to go but i made it for like $20 . You can use a circuit to manipulate the voltage and such.

Does it make any sense.


----------



## Refiner232121

This is a fantastic project but anyone that does not know the basics of electronics it is better to just buy a rectifier and get on with business.
You have to remember that when a person is not familiar with the common electronic terms this task becomes impossible.
If anyone can do this in a picture form it would help
For example where does the transformer go in this project where to attach all the wires and things like that


----------



## Junkman Jim

How about some pictures?

Junkman Jim


----------



## Frankk12

Hi JIm
That is fantastic
I will have more questions later on
Thanks very much


----------



## Frankk12

Hi Jim
I named the parts
I am sure that some of them a wrong
If you can correct me on that it would be nice
If you can tell me the power of each part
For example the size of the transformer and the other parts

I wrote what is this for a knob
I am not sure what that does

I could see the on and off switch 

Also where is the negative and positive lead


----------



## Frankk12

Here is the picture


----------



## Frankk12

Here is the picture 
I hope it works this time


----------



## Frankk12

It doesnt look like I can post the picture

I was naming the parts
I said that there was a 
2 meter
resistor
transformer capacitor 


I wanted to know what the knob in the back was
Thanks


----------



## Harold_V

Frankk12 said:


> It doesnt look like I can post the picture


Have you observed the size limitations that restrict acceptable picture posting?

Harold


----------



## Frankk12

Thanks Harold
Here is another try


----------



## Frankk12

The picture is the same size as Jim posted
I made it even smaller


----------



## Refiner232121

Hi Jim
Thanks for hose pictures
There are 3 main parts
1 is the red part
2nd is the blue 
the 3rd is the one in the corner
Can you name them and how powerful they are


----------



## Junkman Jim

All,
The hardest part of this power supply is finding the two transformers. The first is a variable transformer or Variac, I looked on ebay and they are available there. You'll need 2.25 amps or more. The second one will be difficult if not impossible to find so I built my own.
I started with a transformer with a primary (input) of around 240 watts or about 2 amps. The ratings on the secondaries don't really matter. The primary is almost always the closest winding to the center of the core. Very carefully remove all of the secondaries from the core. Now the fun begins, we must find how many turns it takes to get our required voltage. Wind several wraps of wire around the primary, plug the transformer in, and measure the voltage across the secondary. We are looking for just over 3.5 volts AC on each side of the center tap or 3.5 volts AC on two identical windings (for a bridge rectifier) which will increase to about 5 volts DC when rectified and filtered. Now we know how much wire we need. I used insulated stranded AWG 8, it's alot easier to wind than solid AWG 8. AWG 8 is capable of about 25 amps in a transformer. Once you get the secondary wound be sure that the voltage on each side of the center tap or both windings is the same.
Junkman Jim

A note for Refiner232121:
The red part is the homemade transformer explained above.
The blue part is the filter capacitor, 30,000 uf at 10 volts.
The part in the corner is the Variac, 120 volts at 2.25 amps.


----------



## Refiner232121

Hi Jim 
Thanks very much for your help
What you have in the box seems very simple but it requires skilled electrician to get the job done
I will buy a rectifier that is being sold by a jewelery tool suppliers.


----------



## golddie

SILVER CELL PICTURE: http://www.search-nj.com/Pics/Silver_Cell.jpg

This is a picture someone posted in another thread
I am wondering if a powers supply like this one can be used for this project


----------



## goldsilverpro

That's a different deal, golddie. It looks like a tarnish remover to me. Although they call it a silver cell, it bears no resemblance to the ones covered on the forum.


----------



## Anonymous

Junkman Jim said:


> All,
> The hardest part of this power supply is finding the two transformers. The first is a variable transformer or Variac, I looked on ebay and they are available there. You'll need 2.25 amps or more. The second one will be difficult if not impossible to find so I built my own.
> I started with a transformer with a primary (input) of around 240 watts or about 2 amps. The ratings on the secondaries don't really matter. The primary is almost always the closest winding to the center of the core. Very carefully remove all of the secondaries from the core. Now the fun begins, we must find how many turns it takes to get our required voltage. Wind several wraps of wire around the primary, plug the transformer in, and measure the voltage across the secondary. We are looking for just over 3.5 volts AC on each side of the center tap or 3.5 volts AC on two identical windings (for a bridge rectifier) which will increase to about 5 volts DC when rectified and filtered. Now we know how much wire we need. I used insulated stranded AWG 8, it's alot easier to wind than solid AWG 8. AWG 8 is capable of about 25 amps in a transformer. Once you get the secondary wound be sure that the voltage on each side of the center tap or both windings is the same.
> Junkman Jim
> 
> Hi Jim you did some nice work on your cell and power rectifier. I also like the look of the end product (silver) congratulations..
> Jim I have a question for you. I own this variable12-15 volt 16 amp rectifier, *as you can see it is not this years model lol*. This rectifier as you can see on the front panel has different taps for input voltage. Do you know what will happen if i wire it on the 240v taps and plug it into a 120v socket ? Will I BURN THE COIL ?
> How much will my output voltage drop? What will be the max. output amperage?
> 
> Thank you for your help
> Azrael


----------



## Junkman Jim

Azrael,
First of all use caution, the rectifier is selenium which is poison when over heated. Don't overload this power supply.
If you set the taps for 240 volts and input 120 volts you will get 6 volts at 16 amps at the output.
It looks to me like the transformer is mechanically variable as opposed to an electrically variable one. This type transformer does not have much variation, in this case the variation is only about 3 volts and if you configure it as above it will only have a variation of about 1.5 volts. If you insert a Variac (electrically variable transformer) before the input transformer this supply would output 0 to 6 volts but only at 16 amps.
Hope this helps,
Junkman Jim


----------



## PreciousMexpert

azraelriz 
You must have asked around to see if that thing had a collectible value or not.
What did they say


----------



## Anonymous

Junkman Jim said:


> Azrael,
> First of all use caution, the rectifier is selenium which is poison when over heated. Don't overload this power supply.
> If you set the taps for 240 volts and input 120 volts you will get 6 volts at 16 amps at the output.
> It looks to me like the transformer is mechanically variable as opposed to an electrically variable one. This type transformer does not have much variation, in this case the variation is only about 3 volts and if you configure it as above it will only have a variation of about 1.5 volts. If you insert a Variac (electrically variable transformer) before the input transformer this supply would output 0 to 6 volts but only at 16 amps.
> Hope this helps,
> Junkman Jim




Hi Jim thank you for the information, all your observations on this unit are exact. Yes this is something people must know on this newsgroup, when welding, grinding or heating with a torch any metal contaminated with selenium the fumes are poison. Work safely!

Regards
Azrael


----------



## Anonymous

PreciousMexpert said:


> azraelriz
> You must have asked around to see if that thing had a collectible value or not.
> What did they say



This charger belonged to my father, and my mother who is emptying the basement wants to get rid of it.
I have looked around and haven't found any info on its collectible value.
This maybe the last of its kind. It still works I tried it yesterday.
I will try to find it a home.


----------



## butcher

I like your power supply, thats a nice diode rectifier, what year? I have an old tungar diode tube(they look like large light bulbs), battery charger 1910.


----------



## Anonymous

butcher said:


> I like your power supply, thats a nice diode rectifier, what year? I have an old tungar diode tube(they look like large light bulbs), battery charger 1910.



I do not know. I would say about 195?


----------



## aflacglobal

http://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=39&t=5195

http://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=50&t=3940

http://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=50&t=732


----------



## butcher

That cat's always busy digging up good stuff.


----------



## aflacglobal

You would not believe the reading i do. It's cold and all i have to do right now is read, clean scrap, and read. When i run across something good i bump the thread.


----------



## Refiner232121

I have already made a cell like jims and hopefully I will start refining with this cell.

I used to do Rhodium plating with this machine
It was a while ago and I even forgot how I did the Rhodium plating
The machine is 
VIGOR ELECTRO-PLATER
PM 260 A 
It looks similar to these rectifiers
http://www.shorinternational.com/Rectifiers.htm

There is only one knob for adjusting the volts and an on and off swith
I am able to adjust the volts from 0-12 I see that the max volts is higher but the knob cant make it go higher.

The problem is the Amperes.
It is at zero and it is not adjustable.

Why cant i adjust the Amperes.
Can I do electro refining with this machine.
Is there a way to adjust the Amperes or should I leave it at zero
Thanks


----------



## goldsilverpro

> The problem is the Amperes.
> It is at zero and it is not adjustable.
> 
> Why cant i adjust the Amperes.
> Can I do electro refining with this machine.
> Is there a way to adjust the Amperes or should I leave it at zero


http://www.shorinternational.com/Rectifiers.htm

In my estimation, this is the best type of power supply you could use, for plating or electro-refining. Not necessarily the brand, but the type. How many amps is yours?

Many common plating rectifiers only go to 12V, even though the meter scale goes higher. Note in the Shor link, the first only goes to 10V and the other two to 12V. 12V is plenty for about anything I can think of. The silver cell operates between 3V and 4V.

No current will flow unless you have a load. To test it, turn the rectifier on and then turn the knob completely down to zero - the voltage should read zero. Clip the two leads together and *BARELY* turn up the knob - just a hair. Watch the ammeter while doing this. You should see the amps increase as you turn up the knob. Whatever you do, don't turn it up so much the ammeter pegs. If there is any current flow noted on the ammeter, it's working fine. Turn the knob back to zero and unclip the leads.

If there was *NO* current flow noted by the test above, there is most likely a fuse burnt out. This is very common. In all three photos, I think I see fuse holder at the lower front left of each rectifier. When the leads or electrodes are inadvertently shorted together, the fuse blows to protect the ammeter. Replace the fuse, turn the knob to zero, clip the leads together, turn up the knob a tiny amount, and see if you get current flow. If you don't get any current flow here, the rectifier has more serious problems. Sometimes, this will be a blown ammeter. Also, on some rectifiers, there is a second fuse, usually on the back - check for it. All in all, though, just replacing a blown ammeter fuse (on the front panel) will fix it about 99% of the time.


----------



## Refiner232121

Hi Chris
Thanks for your help
10 amps
20 volts
But i think the meter does not go all the way for the volts

I bought this power supply second hand but it was hardly used
Also I did Rhodium plating but not that much
So it is in good shape.

I accidently had the 2 clips touching each other and the knob way turned on all the way 
and I pluged it in like that because I was not aware of it
There was a buzzing sound but that was about it

I tried what you said


> Clip the two leads together and BARELY turn up the knob - just a hair. Watch the ammeter while doing this. You should see the amps increase as you turn up the knob. Whatever you do, don't turn it up so much the ammeter pegs. If there is any current flow noted on the ammeter, it's working fine. Turn the knob back to zero and unclip the leads.



when I clipped the 2 leads this is what happend
- When I turned the centre knob the amp meter moved but the volt meter just stayed put.

I clip one end to a stanless stell ruler
the other end to a pair of pliers
This is what happend
-the meter for the volt moved and not the amps

If I test this wthout anything on the clips this is what happens
-I am able to adjust the volts from 0-12 
but not the amps

My question is this ¸
How can i get the 
1.25 volts measured at the cathode and anode
2.5 amp 
Like jims cell
Thanks


----------



## AKDan

From your description of the tests you performed, all indications are that your power supply is working correctly.

In this test you performed, unless the steel ruler and the plyers were touching you will see the volts rise, but no current flow jsut as you noted.

"I clip one end to a stanless stell ruler
the other end to a pair of pliers
This is what happend
-the meter for the volt moved and not the amps"

In this test you performed, it is exactly the same as the first test, with the same results.

"If I test this wthout anything on the clips this is what happens
-I am able to adjust the volts from 0-12 
but not the amps"

The way you will get the adjustment in your cell is by simply hooking it up for use and adjusting your power supply voltage to the desired number of volts. As the solution becomes filled with impurity you will see the volts reduce and the current rise.

As the system operates you will simply need to adjust it accordingly. If the amps start going to high, back off the knob, or clean the cell.


----------



## goldsilverpro

> when I clipped the 2 leads this is what happend
> - When I turned the centre knob the amp meter moved but the volt meter just stayed put.


When you turned the knob and the amps went up, the volts went up also, It was just such a small amount (because of the very low resistance) that it was nearly imperceptible to you. 



> If I test this wthout anything on the clips this is what happens
> -I am able to adjust the volts from 0-12
> but not the amps


For any current to flow, you must have a complete circuit. When a plating cell is hooked up between the 2 power supply leads or when you clip the leads to each other, you have a closed circuit. When the leads aren't both hooked to any ONE SINGLE THING, you have an open circuit and no current will flow.



> My question is this ¸
> How can i get the
> 1.25 volts measured at the cathode and anode
> 2.5 amp
> Like jims cell


You can't. It would be foolish to want to do it anyway. In a circuit, there is voltage, amperage, and resistance. The resistance is fairly constant in the system. For a constant resistance, when you raise the amps, the volts will decrease - and visa versa. When plating, you normally set the amperage and let the voltage fall where it may - or, visa versa. In your system, you likely have a different system resistance than Jim does. Therefore, when you set it at 1.25 V, the amps will not likely be 2.5 A. But it makes no difference. If you run a silver cell, set the amps and let the volts be whatever the resistance in your system wants them to be.


----------



## Refiner232121

Hi Chris and Akdan
Thanks for your explanation.
I really appreciate your help


----------



## BusinessMan

Once the nitric solution becomes unable to refine anymore how can I make is so that I collect the silver
Do I hang a copper in there
Thank You


----------



## Harold_V

BusinessMan said:


> Once the nitric solution becomes unable to refine anymore how can I make is so that I collect the silver
> Do I hang a copper in there
> Thank You


A great deal depends on what you have in solution. If silver is but a trace of the contained values, you may be better off recovering with HCl or salt. The resulting silver would be much cleaner. Otherwise, if your solution is quite clean, yes, use copper. When that becomes your choice, make sure you have consumed the vast majority of the free nitric, although a trace is actually desirable. Use large pieces of copper, not wire. Wire tends to break up as it is consumed, making it almost impossible to remove when cementation is complete. That defeats the purpose of the operation. By using large pieces, you can fish them out when all the silver is down. The only exception to the use of wire might be if you have a huge amount of silver in solution and you know you'll consume all of the wire before exhausting the silver in solution. When all the wire is gone, you an then add some large pieces to complete recovery. 

Harold


----------



## metatp

Harold_V said:


> The only exception to the use of wire might be if you have a huge amount of silver in solution and you know you'll consume all of the wire before exhausting the silver in solution. When all the wire is gone, you an then add some large pieces to complete recovery.
> Harold


This is what I do. Not wire wire, but other small pieces of copper. It works very well when you know approximately how much silver is in solution. I also stir the solution every now and then and wait at least a day before I add the large piece of copper.

Tom


----------

