# How to Assay Silver?



## jedrickj (Feb 3, 2010)

Hey all,

Yes I'm a noob here. But I've been lurking for some time. I've built a nice silver cell and its producing silver for me from sterling scrap. I've read just about everything I can get my hands on here and on the 'net in general but I haven't found anything that describes exactly how one would assay the silver my cell is producing. Can someone point me to a post that describes how I'd do this (if possible) on a small scale? I'd like to know how for quality control. Something I read on the net mentioned "titration", but I couldn't find anything specific despite searches here and in google.

Rick


----------



## jedrickj (Feb 4, 2010)

Hmmm, I found Harold's discussions about taking some of the crystals from the last batch and using them to make the next batch of electrolyte and looking for blue color. So let's assume I do this and notice no blue color, or any color for that matter. Can I assume I'm getting at least 999 fine silver from the cell? I do have a professional assayer I know here in town (Austin, TX) and could go that route every X number of bars.

Regards,
Rick


----------



## goldnugget77 (Feb 4, 2010)

Hi Rick
There are some very good threads on this subject 
I dont have the link but if you do some reasearch you will find them


----------



## jedrickj (Feb 4, 2010)

Thanks Gold I'll dig some more 

Rick


----------



## qst42know (Feb 4, 2010)

I haven't accumulated enough silver to run a silver cell as yet but from what I understand sterling will quickly contaminate a cell.


----------



## goldsilverpro (Feb 4, 2010)

These threads might get you started.
http://www.goldrefiningforum.com/phpBB3/search.php?keywords=volhard&terms=all&author=&sv=0&sc=1&sf=all&sk=t&sd=d&sr=posts&st=0&ch=300&t=0&submit=Search

Basically, this titration method is fairly easy but you have to be very good at it to be able to determine even 99.9% purity. If your silver is actually 99.99% purity, which it could be, considering it went through a silver cell, you won't be able to determine this by titration or by fire assay. About the only way of analyzing high purity metal is to send it to a lab that has equipment that will analyze the impurities in the silver. These impurities are totaled and this total impurity percentage is subtracted from 100%. The result is the silver purity.

Silver must be at least 99.9% in order to be considered "Pure Silver". After melting and casting it into a bar, one can tell by the type of crystal (or lack of) formation on the surface whether or not it is at least 99.9% pure. This is usually what an astute buyer first looks at. Much silver which has this crystal formation is bought and sold without requiring an assay. When it doesn't have this crystal or, when the crystal pattern has been buffed off (never do that), the purity is in doubt and the buyer should require an assay.


----------



## Oz (Feb 4, 2010)

Here are some pics of what Chris is talking about when speaking of the crystallization. These are not fine silver, they are just cast cement silver but do run about .99 as I am rather careful with the washing procedures of my cement. They have also been placed in warm 10% sulfuric to clean off any borax flux. You can see that the crystal structure is finer on the bar on the right, this is because it was allowed to cool more rapidly than the other. Because of the faster cooling it has the typical pitting in the center from the rapid off-gassing of oxygen.


----------



## jedrickj (Feb 4, 2010)

qst42know said:


> I haven't accumulated enough silver to run a silver cell as yet but from what I understand sterling will quickly contaminate a cell.



I've read all I can get my hands on here about that, and I've seen the arguments about starting with some copper in electrolyte and Harold's preference of no copper to start. And how copper accumulates and on and on. How it may or may not affect crystal structure. Other posts suggest the cell can tolerate something like 12 oz/gal of copper before copper starts plating out. I'm well within that threshold and use conservative estimates on the amount of copper in solution. My scrap bars are either high grade sterling or cemented silver. I've got one tank running sterling now and I plan on building another for doing cemented silver then I'll take both to a professional assayer here in Austin (Allen McMurtry, AMC Company) and see what I get back and what can be tolerated and I'll go from there.

I get sheet sterling jewelry scrap from my own work and students in my jewelry class. The guy who runs the school sells me his scrap along with many of the students. I've got around 200 oz net silver so far. Yes I'm small potatoes. I'm still learning how much loss there is in a run and other factors. The biggest win for me on sterling scrap is its easy to sort it, pour it into a bar, and hook it to the anode and wait for a few hours. I'm stepping in slowly. Although this is my first posts here, I've been reading and learning now since late 2008. So I feel I haven't rushed in to this. It has become an all consuming passion. I'm trying to figure out how to build it up and make it my full time profession. But it will take time and I'm in no particular hurry. I read here as much as I can to find an answer to my questions before I ask. And I was having troubling finding stuff on assay. There is a huge amount of information here to digest.  Oh and I haven't even started reading the gold refining threads yet. 

Finally... I really have to thank all of the folks here, Harold, Lazersteve, GSP, Oz, 4metals and on and on. Too many to list them all. I've been reading your posts for some time and I'm getting to feel like I know all of you even though we've never met. You guys do us "new kids on the block" a tremendous service by providing information on your experiences in this industry. Thank you all so very much. 

And BTW if any of you out there happen to be in Austin maybe we can meet for a beer sometime and compare notes and techniques and what we've learned. Just a thought.

Rick


----------



## jedrickj (Feb 4, 2010)

goldsilverpro said:


> These threads might get you started.
> http://www.goldrefiningforum.com/phpBB3/search.php?keywords=volhard&terms=all&author=&sv=0&sc=1&sf=all&sk=t&sd=d&sr=posts&st=0&ch=300&t=0&submit=Search



Thanks GSP. Yes it did get me started. Enough so to realize I will just pay for assay for now  Not ready for that level of effort. And I read just about everything you post here 

Rick


----------



## jedrickj (Feb 4, 2010)

Oz said:


> Here are some pics of what Chris is talking about when speaking of the crystallization. These are not fine silver, they are just cast cement silver but do run about .99 as I am rather careful with the washing procedures of my cement. They have also been placed in warm 10% sulfuric to clean off any borax flux. You can see that the crystal structure is finer on the bar on the right, this is because it was allowed to cool more rapidly than the other. Because of the faster cooling it has the typical pitting in the center from the rapid off-gassing of oxygen.



Question.... Here's the setup
Very cool and good to know Oz. I pour a 500 gram Dore bar for the anode and I melt it in a 1 kilo melt furnace at 1800 degrees, give it few stirs and go into a cast iron ingot mold with a bit of motor oil on it. I don't use fluxes. 

And here's the questions...

Once I dump the bar out of the mold I notice the pattern on the bars you have pictured right around the middle on the bottom of the bar. Why is that happening with sterling? Is the melt furnace separating the metals out in some way? (I thought something was wrong with the bar for doing that pattern. (silly me) And... should I be doing something different to get a more homogeneous ingot?

I'm really weak when it comes to melting and pouring bars. I've not melted and poured any of my fine crystal yet. To be honest it scares me. All this work and I worry about ruining it somehow. Any pointers on what temp to use and whether or not fluxes are necessary when pouring pure silver.

I will be pouring into 10 oz graphite ingots with a borium nitride release agent sprayed on. I was planning on 1800 degrees on the furnace and no flux. Is any of this bad?

Oh and thank goodness for your pictures. I'd have had a cow when I poured my bars and seen that pattern. I would have thought I screwed something up. LOL

Rick


----------



## goldsilverpro (Feb 5, 2010)

jedrickj,

It would be very helpful to see photos of your cell. I assume your furnace is electric since you say you are controlling it at a definite temperature - 1800F. Can you describe your furnace? Were I you, I would consider building a gas crucible furnace



> Once I dump the bar out of the mold I notice the pattern on the bars you have pictured right around the middle on the bottom of the bar.


I don't understand what you are trying to say here.

When I was living in Houston, I think I remember sending some sort of oddball fire assay sample to that lab in Austin, before I had a fire assay setup. If he will be using fire assay to check the purity of your silver, I think you are wasting your money. For several reasons, fire assay is just not reliable for this high purity range, even when running proofs. Gold, yes. Silver, no. Find out what method he will be using and check with us before you do it. 

I've probably made more money in my life refining silver than I have refining gold. For every silver refiner, there are probably 10 or 20 gold refiners. There is a lot more silver scrap out there than gold scrap. Sterling is only one of many types.

Austin is my favorite city in Texas. I've lived in Dallas (went to college at SMU), San Antonio, and Houston. My son now lives in Mansfield. I've always wanted to live in Austin.

Chris


----------



## peter i (Feb 5, 2010)

jedrickj said:


> I get sheet sterling jewelry scrap from my own work and students in my jewelry class. The guy who runs the school sells me his scrap along with many of the students.



I would not refine the clean sterling scrap, just cast it into grains and sell it as casting grains.

More profit, less work :mrgreen: 

When I refine coin silver for casting jewellery, I only refine part of it, then use the unrefined alloy to alloy my fine silver to sterling.
(I'm using Swedish "1 Crown" which is dependable source to a consistent alloy.... I would not do it with suspicious coins, they would all be refined.... then alloyed with Swedish silver))


----------



## jedrickj (Feb 5, 2010)

goldsilverpro said:


> jedrickj,
> 
> It would be very helpful to see photos of your cell. I assume your furnace is electric since you say you are controlling it at a definite temperature - 1800F. Can you describe your furnace? Were I you, I would consider building a gas crucible furnace
> 
> ...



Yeah my company gave me a choice of Houston, Dallas or Austin when they consolidated here in Texas. Well that was an easy decision! I really like Austin. I generally like college towns.
Thanks for the help!

Rick


----------



## Palladium (Feb 5, 2010)

jedrickj said:


> I've read all I can get my hands on here about that, and I've seen the arguments about starting with some copper in electrolyte and Harold's preference of no copper to start. And how copper accumulates and on and on. How it may or may not affect crystal structure. Other posts suggest the cell can tolerate something like 12 oz/gal of copper before copper starts plating out.
> Rick



I do like a man who reads and does he research instead of just asking questions when even if the answer was supplied to them they still wouldn't understand it because they have gotten the basic underlying understanding of the principles.

Welcome to the forum.


----------



## jedrickj (Feb 5, 2010)

Palladium said:


> jedrickj said:
> 
> 
> > I've read all I can get my hands on here about that, and I've seen the arguments about starting with some copper in electrolyte and Harold's preference of no copper to start. And how copper accumulates and on and on. How it may or may not affect crystal structure. Other posts suggest the cell can tolerate something like 12 oz/gal of copper before copper starts plating out.
> ...



Thank you. I'm so glad I found you all.

Insightful observation and I agree. 

I believe that one can only learn by doing. I try based on what I read, then run into problems, research and adjust, then run into another problem, then research and adjust. Once you've dealt with it and you do ask a question you understand the answers. Unlike the case where you've not tried and gotten your hands dirty (or full of silver nitrate stains in this case) LOL. I hope to be one that contributes here at some point based on my experience and doesn't just ask questions.

I knew silver nitrate would stain before I started, so the few stains I have are small splash spots. We used to use silver nitrate to mark hunting dogs when I was a kid, so that they were easily identified at a distance.

Rick


----------



## goldsilverpro (Feb 5, 2010)

Houston is great for a large city (big town, actually). I was there 8-9 years and miss it. Dallas sucks. SA is also great.

Does the furnace sorta look like this?
http://www.riogrande.com/MemberArea/ProductPage.aspx?assetname=703119&page=GRID&free_text|1265398852006=furnace+electric

Or, this?
http://www.ottofrei.com/store/home.php?cat=1925

Photos of the cell would help. Important if you want to learn. Don't be embarrassed. You should have seen some of the Mickey Mouse things I have set up.



> In Oz's pictures there is that crystal pattern all over the ingots he poured. In my sterling ingots I get that same pattern but centered around the bottom of the poured ingot. It looks to me that the sterling is breaking up when I pour the ingots into fine silver in some place, and copper at the top (the top being the last of the molten metal to leave the crucible.


Are you combining both cement silver and sterling in the same melt? If so, what is the ratio of the mix? What are you stirring the melt with? My guess is that you're not melting hot enough and/or you're not stirring well enough, immediately before you pour. *If* what you see on the bottom is the same crystal as in the photo, the silver on the bottom must be near pure. It's hard to imagine that much stratification. Unless everything melts completely and is blended well, there could be some stratification but, damn. If not stirred, I can see the heavier purer cement silver sinking to the bottom somewhat but, damn. Maybe we need to see a photo of the bottom of the bar. It may be easier to put it on a scanner. That works very well.

If you want to make money from this, you've come to this right place. No where else on the internet will you truly find out how to do this. There are 3 or 4 of us samaritans who have a total of about 80 years of experience doing what you want to do, on a professional level. We can show you how. The most important thing for you to do is to communicate in as much detail as possible, listen, and don't give us any s**t :lol:

Chris


----------



## jedrickj (Feb 5, 2010)

goldsilverpro said:


> jedrickj,
> 
> It would be very helpful to see photos of your cell.
> 
> Chris



Chris,

I would, but I'd be embarrassed to share it. <Rick blushes> One of my lessons learned the hard way... by making a mistake. I bought one of the Shor silver thumb cells from his site. (its also not a thum cell as the name infers) For the money I ended up with a piece of plastic and very sparse misguided set of instructions. (the guide is 2 pages) I thought I was buying a documented guide with chemistry etc..., and I can't return it. A friend of mine likes to say "You don't always get what you pay for, but you damn sure PAY for what you get". And along those same lines. You either win or your learn and one things for sure, you never learn LESS! 

I think Shor is selling myth personally. There is nothing I would call "simple" about any of this until you've lived through it. Its taken me time to learn to toss their guide and adjust based on what I found here. Do they really use this thing, seriously! BTW I won't be buying anything else pre-made unless I check here first.

My adjustments:

1. Toss the cathode bag. The crystals just build in the fibers and make a mess. Most of the crystal grow on the outside of the bag. 
2. Forget the graphite cathode. I use it for a stir rod.
3. I switched to fine silver for the cathode. I took a fine silver coin and ran it through my mill and stretched it out and made it thin. I could have used stainless but I don't have any stainless plate lying around.
4. Forget the numbers in the guide for amperage etc... Cells run where they run based on the size of the anode and cathode it seems to me. I know now I need larger cathode area. My cell is running between 2 and 3 volts and pulls about 6 amps. I turn it down to about a volt when I'm gone so it doesn't over produce while I'm at work.
5. I don't bother trying to harvest the crystals as they build on the cathode. I use Harold's recommendation of just scraping the crystals off periodically into the tank so they don't run and short the rectifier out, I keep changing the dore anode. Once I've run all of my dore bars I will run the electrolyte through a filter then wash the crystals. I haven't done it yet, but I will tap a hole for a bung on the bottom of the tank to drain it without pouring it out. I'll drain through a filter with gravity as I don't have a vacuum (sp?) filter yet. (any articles on how to build a vacuum filter here?) 
6. Forget stannous chloride as a precipitate (what they call silver precip crystals). Its horrible in my experience. To the upside I've got plenty of stannous chloride to make test solution with! 

My suggestion.... Build your own! You'll be glad you did.

When I said built, what I meant was I built out the system of fume hood, table where the cell sits and my process flow. If you would see what I use for a fume hood you'd laugh. I do this in my garage which is enclosed. It however does work as I get no odors in the garage from the system. When I change out liquids I open the garage door 

My new tank will be similar to Thum tanks that I think you and Harold proposed. I'd like to keep it 5 gallons in size. I'm scraping up parts and am looking for a machine shop here in Austin that can make the cathode plate to fit the tank I end up with. I like the stacking anodes, anode basket along with a knob contact mechanism for the anode. I also like just letting the crystal drop and harvesting in a large batch. I will be adding a bottom drain for this system as well to make it easier to recycle the electrolyte. 

My fume hood is a stove exhaust I got for 35 bucks. I screwed 4 2x4's into the corners then toe nailed the base of the 2 bys into a little wooden table. Closed up all the holes with duct tape and then wrapped it in plastic sheet. Coming out of the top is an 8 inch tube that connects to a vent out the side of the garage. Its ugly as hell but it works  I know I will look back on this system someday and laugh till I hurt. More than anything else I'm having a blast, AND IT WORKS! I'm getting really pretty silver crystals from it, but not because of anything Shor told me. Because of the stuff I got here. 

This weekend I will be dissolving the other unclean silver scrap in 50/50 nitric and cementing with copper as well as working on my new cell. Some of the silver I've gotten from my classmates is fused with copper, loaded with solder, and some of it is bench sweeps. I'm coming up with systems for all of this as well. I'm also building a series of buckets for dealing with waste. I know there are tiny amounts of gold in the slimes too. While they do separate gold scrap, there are filings and little tiny pieces of small gauge 18K gold wire in the scrap. I'll be working on figuring out how to get that isolated based on articles I've read here.

Finally we prolly need to move this discussion if it continues as we're getting way off topic of Silver Assay.

Regards,
Rick


----------



## jedrickj (Feb 5, 2010)

goldsilverpro said:


> Houston is great for a large city (big town, actually). I was there 8-9 years and miss it. Dallas sucks. SA is also great.
> 
> Does the furnace sorta look like this?
> http://www.riogrande.com/MemberArea/ProductPage.aspx?assetname=703119&page=GRID&free_text|1265398852006=furnace+electric
> ...



Will Do LOL! Not the least bit interested in biting hands that feed me  And you are quite correct. There is no where else on the net to find this stuff. I tried for some time.


----------



## jedrickj (Feb 5, 2010)

goldsilverpro said:


> These threads might get you started.
> http://www.goldrefiningforum.com/phpBB3/search.php?keywords=volhard&terms=all&author=&sv=0&sc=1&sf=all&sk=t&sd=d&sr=posts&st=0&ch=300&t=0&submit=Search
> 
> Basically, this titration method is fairly easy but you have to be very good at it to be able to determine even 99.9% purity. If your silver is actually 99.99% purity, which it could be, considering it went through a silver cell, you won't be able to determine this by titration or by fire assay. About the only way of analyzing high purity metal is to send it to a lab that has equipment that will analyze the impurities in the silver. These impurities are totaled and this total impurity percentage is subtracted from 100%. The result is the silver purity.
> ...



You are of course correct sir and AMC was honest. When I spoke with Allen he said that he could fire assay but that if I really wanted to know it would have to go to someone with a mass spectrometer that could minus out the impurities and give a true answer. He even referred me to a lab. Alfred Knight in South Carolina. Not sure I'm willing to go through all of that, but I may have no choice. I'm guessing its pricey.

Rick


----------



## goldsilverpro (Feb 5, 2010)

Alfred Knight is way too famous and too expensive. Ask 4metals and/or Lou how to get this done.


----------



## qst42know (Feb 8, 2010)

> 1. Toss the cathode bag. The crystals just build in the fibers and make a mess. Most of the crystal grow on the outside of the bag.



The bag is for the silver bar which would be the anode correct?

It's supposed to keep gold and PGMs from ending up in your silver crystals. You said you just scrape the silver to the bottom and gather it later. 

This is just a guess on my part but wouldn't a tiny amount of PGMs dramatically affect the appearance of your bar?


----------



## jedrickj (Feb 8, 2010)

qst42know said:


> > 1. Toss the cathode bag. The crystals just build in the fibers and make a mess. Most of the crystal grow on the outside of the bag.
> 
> 
> 
> ...



Yes I use the bag for the anode to catch the slimes, and I save those off because I do expect trace amounts of gold in the slimes. This is a Shor system and with it he has you use a cathode bag as well as an anode bag to catch the crystals that drop from the cathode. In my experience it just sucks to do that. 

Of the gold that I do expect, I expect it all to be 18k and alloyed with silver. No one seems to be using any platinum anywhere so far as I know. If it shows up, woo hoo I'm getting it for free. I'll figure out what to do with the ugly bar and extract the platinum if it shows up 

I don't know how PGM's would affect things to be honest. I don't have that much experience, but what I will say is that its not likely to contain any. So far my crystals are very nice and shiny. This is all sterling scrap from sheet, wire etc... from known reputable sources in the US. 

Now with that said, I think it was Harold and others that posted *you can tell these new kids but they don't listen*. Some things they have to find out for themselves. Well....

As Harold has said many times, the copper catches up quick in the electrolyte and kills the lifetime of it when going directly from sterling. Its agreed that the crystals are better with a little copper present, but its just not that big a difference as far as I'm concerned and I'm not going to start with copper in my electrolyte from now on. I'm mixing a new batch now. Nextly, I will acid process all of my silver in nitric first and then cement it out with copper, wash it, cast a dore bar and go to electrolysis instead of trying to skip a step. This should yield good 4 9's fine and not kill my electrolyte in the process.

Live and learn. Too bad I just can't listen.


----------



## qst42know (Feb 8, 2010)

The electric furnace may be allowing to much of copper and other additives in the sterling to oxidize. It is why over worked sterling needs to be refined before re-use. 

A pretty anode is not required but perhaps some flux that includes a carbon source (flour, sugar, or charcoal) and maybe a lid on the crucible?


----------



## jedrickj (Feb 8, 2010)

qst42know said:


> The electric furnace may be allowing to much of copper and other additives in the sterling to oxidize. It is why over worked sterling needs to be refined before re-use.
> 
> A pretty anode is not required but perhaps some flux that includes a carbon source (flour, sugar, or charcoal) and maybe a lid on the crucible?



I think so. I'm going to prep a crucible in a few by coating with borax, then do my melt with a bit of borax on top and a powdered charcoal layer. The more pure dore bars are spitting a lot of oxygen when I pour. To the extent of making holes in the bar. The electric furnace just lets too much oxygen get to the silver me thinks. Not, as you said, that pretty bar is necessary for anodes, but its good practice 

Rick


----------



## goldsilverpro (Feb 9, 2010)

jedrickj,

It's a shame you spent all that money on that Electro-melt type furnace. Harold and I hate those things for the many reasons we've given in many past posts. You could have built a small gas crucible furnace for 1/2, or less, of what you spent and had a much better setup.

Check the recent silver cell thread that 4metals was active on. He started his cell with 0.5 oz/gal of copper because, with less, the silver stuck to the cathode until some copper built up in the solution. It seems to me that Harold has said the same thing. Adding that small amount to start won't effect the longevity of the solution that much.
http://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=50&t=6469

There's a photo of the Shor silver cell here. I can't believe they want $495 for it - obscene. Like you said, it's not a Thum cell (which is horizontal). You could have used a 1 gal plastic bucket ($2) and had about the same thing.
http://shorinternational.com/refining.htm

In a Thum cell, from 30 to 50 amps per square foot of anode area is commonly used. I would think the cathode area should be at least as large, area-wise, as the anode area - maybe as much as twice as large. Figure only the area of the anode that is facing the cathode. In a vertical setup, you could use 2 cathodes - one on each side of the anode. In that case, figure both sides of the anode.

A vacuum filter would be nice but, if the crystal is of good hardness (which it will be if you have done things right), a plastic funnel and filter paper work about as well. Good crystal filters and rinses quickly by gravity. The rinses will flow through about as fast as you can pour the water in. You can easily tell when it's been rinsed well enough to remove all the copper solution. Collect a few drops of rinse water from the tip of the funnel, into a small beaker or test tube or spot plate, and add about an equal amount of water-clear household ammonia. With any copper present, the solution will turn blue. It helps to see traces better by holding the beaker or test tube in front of a piece of white paper.


----------



## jedrickj (Feb 9, 2010)

goldsilverpro said:


> jedrickj,
> 
> It's a shame you spent all that money on that Electro-melt type furnace. Harold and I hate those things for the many reasons we've given in many past posts. You could have built a small gas crucible furnace for 1/2, or less, of what you spent and had a much better setup.



Agreed. However In my own defense, I purchased this (at the time) for my jewelry side of things. I'm a silver smith which is what lead me to all of this to begin with. I thought I could use it for this. I do plan on keeping some of my silver for casting and making my own sterling. There are some things you can do to help the furnace oxidation problem. I was able to get good pours with it last night. 

Because I solder silver and heat absorption is a problem I use charcoal blocks for a soldering surface. Come to find out I just put a charcoal block over the little hole in the top of the furnace and this reduces the oxygen intake of the silver. I use boron nitride on the graphite crucible and the ingot mold too. Then when I do the pour I take another charcoal block and cover the ingot mold immediately and let it sit for a minute or two while it cools. Fairly nice looking sunk in the middle ingots with no oxygen expulsion holes doing this. So it can work, you just have to be patient with the thing cuz is stink slow 



> Check the recent silver cell thread that 4metals was active on. He started his cell with 0.5 oz/gal of copper because, with less, the silver stuck to the cathode until some copper built up in the solution. It seems to me that Harold has said the same thing. Adding that small amount to start won't effect the longevity of the solution that much.
> http://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=50&t=6469



I'm not having this problem. The crystals grow pretty quick and they aren't hard attached. Usually a shake or two and most fall off, then I scrape the remaining off with a stainless scraper.



> There's a photo of the Shor silver cell here. I can't believe they want $495 for it - obscene. Like you said, it's not a Thum cell (which is horizontal). You could have used a 1 gal plastic bucket ($2) and had about the same thing.
> http://shorinternational.com/refining.htm



Its a rip off if you ask me. Its unfairly priced for what you get. If it were 100 to 200 bucks I'd probably not complain. But the price tag for what you get is ridiculous. Too bad I didn't know what I know now. The down side is I will not do business with them in the future. So they got my 495 for this thing. How much are they gonna lose over the long haul from me in lost good will. 



> In a Thum cell, from 30 to 50 amps per square foot of anode area is commonly used. I would think the cathode area should be at least as large, area-wise, as the anode area - maybe as much as twice as large. Figure only the area of the anode that is facing the cathode. In a vertical setup, you could use 2 cathodes - one on each side of the anode. In that case, figure both sides of the anode.



I like this idea. I'm going to set this up soon. I was thinking I was going to build another cell, but I may not now. I may just make adjustments to this one and not sink any more money into this for a while. ie. leave it vertical and make modifications.



> A vacuum filter would be nice but, if the crystal is of good hardness (which it will be if you have done things right), a plastic funnel and filter paper work about as well. Good crystal filters and rinses quickly by gravity. The rinses will flow through about as fast as you can pour the water in. You can easily tell when it's been rinsed well enough to remove all the copper solution. Collect a few drops of rinse water from the tip of the funnel, into a small beaker or test tube or spot plate, and add about an equal amount of water-clear household ammonia. With any copper present, the solution will turn blue. It helps to see traces better by holding the beaker or test tube in front of a piece of white paper.



I need the vacuum filter for the cemented copper. Its too fine to handle with stir and decant. I'm losing too much silver and the silver's so fine it clogs up a filter and makes the rinse really slow. The crystal on the other hand is easy to rinse. Thank goodness 

Thanks for all of you input. I've got a lot to learn, but I do learn fast!


----------



## goldsilverpro (Feb 9, 2010)

> I need the vacuum filter for the cemented copper.



I would suggest not buying one of the plastic vacuum filter funnels made by Bel-Art. I'm thinking that Shor sells these, also. I once owned an 18" one and hated it. The problem is that, the way they are designed, it is nearly impossible to get a good seal with the filter paper. I know that they're expensive, but I think the Coors porcelain ones are still the best - they come in several sizes. The only problem with them is that they are limited in size (about 10" dia is the biggest). For some applications, the biggest one they make is not big enough in order to get the production out. For small to medium lots, they can't be beat.


----------



## aflacglobal (Feb 9, 2010)

catfish said:


> Hi Mayhem:
> 
> You need to get yourself a vacuum filter system. You buy the Buchner funnel, whatman filters 1.5 and filter beaker on eBay. Don’t buy the cheap plastic pump they advertise. Buy your vacuum pump from harbor Freight Tools. The pump costs about $15.00 and you get a reservoir jar and plenty of adapters and hose with it. It is a heavy duty metal (brass) pump. I ruined two of the plastic pumps before I got smart and started using a drip jar in series with the beaker and pump. The acids will ruin the pump in seconds. If you need any info on this rig hit me back. The vacuum will save you a lot of time and the filters work much better than the coffee filters. You can buy different media type filters too. I found that the whatman 1.5 works best for me.
> 
> ...



I think i know what he is talking about, but Chris could you fill in the blanks about anything special ?


----------



## goldsilverpro (Feb 9, 2010)

Sorry, Ralph, but I don't really understand what Tom is saying.


----------



## jedrickj (Feb 9, 2010)

Chris,

What about this setup and the Harbor Freight vacuum pump?

http://www.labmiser.com/storefrontprofiles/DeluxeSFItemDetail.aspx?sid=1&sfid=167854&c=0&i=239534494

Or would you recommend something else?


----------

