# Silver Contacts Removel Proceedure



## Anonymous (May 18, 2010)

I was going to run everything through the hammer mill, that is until I realized most of the contacts are only plated onto a copper rivet.

Since I have a lot of time on my hands decided to rig up a small shop grinder with a water spray to catch the dust. The pump I used for the circulating the water is actually a diaphragm air pump and it works pretty slick.

By using the grinder I'm able to tell right away which contacts are solid and those that are plated, the plated ones I just grind the surface off and collect all the solid ones by grinding the backside of the rivet off.

I have the grinder sitting on a couple of boards to keep the base out if the water, the start capacitors are located in the base. If you decided to use the idea do so at your own risk and use of judgment.

Happy Refining and stay safe.
Gill


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## machiavelli976 (May 19, 2010)

it is a good ideea if you know how to deal with electric current and water together. i preffer to burn to hell the plated buss bars and quench them . the solid silver remains white even it was filthy before.


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## Anonymous (May 19, 2010)

machiavelli976 said:


> it is a good ideea if you know how to deal with electric current and water together. i preffer to burn to hell the plated buss bars and quench them . the solid silver remains white even it was filthy before.



Your not recovering the plated contact silver which is possibly more valuable having been alloyed with other precious metals. Also by just grinding the plated silver off is going to save on acids and time involved to refine. 

The start caps should only be hot when the start relay contacts are closed and not while running. I use Ground Fault circuit breakers for out my outdoor outlets.

Besides I would never expect anyone to follow my suit, all lapidary grinding equipment is designed to run wet. If you are a bit more ambitious than I you could redesign the grinder set up to meet your needs. I'm very lazy and tend to take the path of least resistance.

Over the winter months cut thousands of contacts free with side cutters and come up with carpel tunnel.

Best Regards
Gill


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## machiavelli976 (May 19, 2010)

after many years of silver contact recovery i can tell blind wich is solid contact button and wich is not. some of the buttons are half silver half copper. silver plated copper buttons have found them in cheap relays and breakers made by chinese. i have never met solid silver buss bars. i use quenching only to strip the silver plated copper bars for use in cementing.


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## Anonymous (May 21, 2010)

machiavelli976 said:


> after many years of silver contact recovery i can tell blind wich is solid contact button and wich is not. some of the buttons are half silver half copper. silver plated copper buttons have found them in cheap relays and breakers made by chinese. i have never met solid silver buss bars. i use quenching only to strip the silver plated copper bars for use in cementing.



The contacts I'm going after are from washing machine and dryer timers along with hot water tank rheostats. I found grinding the best solution to remove these smaller contacts.

To remove the contact buss from the rheostats from electric ranges, I fill a plastic pail 1/3 full than ram it with a steel bar breaking the Bakelite making removal of the buss with the contacts an easy task.

Like you I do sweat the larger contacts off the buss bars, this afternoon I grabbed a bucket that had some discarded bars in and found that there was still a lot of available silver left on the bars. Likewise I ground these off, I was really surprised to find how deep the silver penetrates into the copper buss bars.

I think the hour spent on this job was time well spent and that it will pay handsome dividends.

Best Regards
Gill


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## machiavelli976 (May 22, 2010)

best before quenching is to let the hot silver plated copper bars to cool some seconds . this way the black copper oxide will become thick enough to strip itself a little. i still have some huge buss bars (six pieces-ten kilos) and i think to run your idea about grinding under water stream. not concerned about the silver gain but the idea really caught me !


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## wavecrazed (May 22, 2010)

Here is a contact I found floating on the floor in the back of the scrap truck. It does test + for silver (see red). Can I cut off with snips and use some chemical to dissolve it off the copper?


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## Anonymous (May 23, 2010)

wavecrazed said:


> Here is a contact I found floating on the floor in the back of the scrap truck. It does test + for silver (see red). Can I cut off with snips and use some chemical to dissolve it off the copper?




Credits Wickapedia: As beryllium compounds are toxic there are some safety concerns for handling its alloys. In solid form and as finished parts, beryllium copper presents no particular health hazard. However, breathing its dust, as formed when machining or welding may cause serious lung damage.[2] Beryllium compounds are known human carcinogens when inhaled.

If you were to grind that silver contact you'll find that the button is fairly heavily plated onto a copper rivet, it's because of the beryllium copper that I have a water source on the grinding wheel to catch the dust. Fortunately most of the buttons were only plated and that I did not have to grind everything off the spring to which it is attached.

You may thing the silver contact is a pure button, but is not. I would bet the farm on it.

Best Regards
Gill


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## machiavelli976 (May 23, 2010)

hi wavecrazed ! the picture above tells me it is about a solid silver button. maybe 90% AG and 10% Cu. i might also be wrong ! anyway it is brazed to the buss bar ,so you can remove it by heating to red (about 700 *C) stay away from the fumes. CdO is almost always present !


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## Chumbawamba (May 23, 2010)

Call me a masochist but I don't mind (so much) spending time pulling contact points out of the fins (I guess you guys are calling them buss bars?) using mechanical methods: i.e. my fingers and a series of tools, including diagonal cutters, needle nose pliers, small general purpose pliers, and tweezers. I'm usually able to extract the button without too much toil (a few seconds per button). Not the most efficient method, but it passes the time as I smoke my stuff.

I separate out the ones that look to be pure silver (or at least not silver plated copper rivets) from the rest. I also pass a magnet over all of them to root out the ones that are magnetic. Not sure what metals would make them magnetic (Ni? Pd? Pt?) but I keep these in a separate container.

I plan to eventually refine everything with acids. Even if one were to go the more efficient route of simply cutting off the button with as little buss bar left as possible, it seems the best route is dissolve in acid, test for the presence of various PMs, then drop out the various metals as needed.

Me thinks the grinder is a bit overkill, but whatever works for you


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## machiavelli976 (May 23, 2010)

Chumbawamba, you're not masochist at all. mechanical , is the best way to pull out the buttons if the size is not too big. maybe up to half of an inch. i don't see you using even a diagonal pliers for a four pounds buss bar ! for me heating is the solution to every contact point larger than 1 cm.


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## qst42know (May 23, 2010)

If they are all rivet type and solid I have good luck with a flat ended nail set and a piece of steel with several size holes drilled through. Your punch should be flat on the end so you don't flare the rivet more and just about the size of the rivet hole. The hole in the steel should just clear the contact and then drive the rivet the opposite way they were put in.


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## Anonymous (May 23, 2010)

Chumbawamba said:


> Me thinks the grinder is a bit overkill, but whatever works for you



I agree the grinder is overkill, but look 880 grams of silver ready to refine with next to nothing for copper from the rivit. 

Because it's mostly granular this stuff is going to digest really fast with next to nothing for acid use.

Best Regards
Gill


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## Chumbawamba (May 23, 2010)

Nice! But how much of it is silver and how much is other stuff? Have you done any stannous tests on it yet?

And where are you guys finding contact points larger than 1 cm? I'm lucky to find 5mm contact points in the various relays and switches I've opened so far, and I've opened a lot.

I have waiting some high voltage Cutler-Hammer breakers and relays that were too old/obsolete for resale. I think those should have some good silver.


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## Anonymous (May 23, 2010)

Chumbawamba said:


> Nice! But how much of it is silver and how much is other stuff? Have you done any stannous tests on it yet?
> 
> And where are you guys finding contact points larger than 1 cm? I'm lucky to find 5mm contact points in the various relays and switches I've opened so far, and I've opened a lot.
> 
> I have waiting some high voltage Cutler-Hammer breakers and relays that were too old/obsolete for resale. I think those should have some good silver.



Nothing in acid yet, stannous on standby, hopefully it will show some palladium, making all this work worthwhile.

Yea a 5mm contact is a large one for me also, most of my contacts came from electric range rheostats mostly plated some on steel rivets while others are bonded to copper, the oven rheostat has 5mm solid silver contacts. Upper and lower thermo-disk rheostats from hot water tanks also 5mm contacts the older tanks had round solids the newer tanks have a square contact which are heavily silver plated over copper.

Washing machine timers have a center row of double sided contacts, most are solid silver while some pins will have plated, the outside contacts facing the center row are only silver plated on the inside face.

There's 5 pails of contacts in that small jar of silver.

Best Regards
Gill


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## Barren Realms 007 (May 23, 2010)

gustavus said:


> Chumbawamba said:
> 
> 
> > Nice! But how much of it is silver and how much is other stuff? Have you done any stannous tests on it yet?
> ...



When you say a pail I guess you mean a 5 gal pail? It all adds up in the end.


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## qst42know (May 23, 2010)

All from clad contacts?

Can't argue with results. :mrgreen:


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## Anonymous (May 23, 2010)

qst42know said:


> All from clad contacts?
> 
> Can't argue with results. :mrgreen:



Yes 90 percent were clad, the oven contacts I found are always solids and some older hot water tanks.

These are easy to remove from appliances using a claw hammer, when you have enough to tackle, fill a plastic pail 1/3 full then smash everything to a pulp with a heavy bar. I used a 2" solid steel shaft 4 feet long.

Once you have everything pulverized it's easy to pick out the contacts. 

In total I have approximately 3.5 lbs of silver recovered from the same type of material, I was hoping to have this last bunch picked clean over winter but other projects kept me busy.

My recent yard clean up notice from the RM helped to get this project back on line, I needed the garage space taken up by the pails just sitting there taking up space. I'm going to purchase a CNC milling machine and lock myself in my shop, the RM can go where the sun don't shine.

By the way it was a good thing my Quonset burned to the ground, at our new property in a different RM we have a building inspector for that RM that is from hell. I would have had to have an engineers report on the building before it could have been re-erected. I can not use lumber from a local sawmill for outsdie buildings like shop and barn with out having it graded God works in strange ways.

Building inspector for this RM only requires a relocation permit for a used building, and he lets you use the ungraded lumber form the same local sawmill for shop and barn - go figure.

Best Regards
Gill


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## butcher (May 23, 2010)

I cannot wait to see the results from these contact points.
I was hopping that that big heated shop missle silo would work out, but I know you will come with another shop, which may work out better.


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## Anonymous (May 24, 2010)

Using the grinder to remove the plated silver I ran into some plated silver over steel some of which came down with the silver.

Wondering if it's safe to assume that I can add HCL to the silver filings to remove the iron with out having any effect on my silver. After a few minutes the diluted acid did get a bit warm so some reaction took place.

Best Regards
Gill


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## Harold_V (May 25, 2010)

gustavus said:


> Using the grinder to remove the plated silver I ran into some plated silver over steel some of which came down with the silver.
> 
> Wondering if it's safe to assume that I can add HCL to the silver filings to remove the iron with out having any effect on my silver.


Yep, perfectly safe. Just don't boil. 
I often did an HCl wash of my recovered cement silver when processing contacts that were made of tungsten carbide. The amount contained was obvious by the deep ink blue solution that came from the wash cycle (very different from the blue color from nickel or copper). I noticed no conversion of silver to silver chloride, not even with the huge amount of surface area presented by the recovered cement silver. 

If all else fails, dissolve the silver in dilute nitric, then recover with copper. You will have eliminated the vast majority of iron in the process. Do be careful to insure that you dissolve everything with nitric, as any remaining iron will cement silver until it is exhausted. Stainless, should it be included, shouldn't be a problem, and can be eliminated in filtering. 

I would recommend an incineration process after the HCl wash, prior to applying dilute nitric, to insure you have eliminated all chlorides.

Harold


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## Anonymous (May 25, 2010)

Harold_V said:


> gustavus said:
> 
> 
> > Using the grinder to remove the plated silver I ran into some plated silver over steel some of which came down with the silver.
> ...



Yes I will incinerate you rid the chlorides before introducing the nitric, Harold this afternoon when I melted the big bar of silver also recovered from contacts it showed blue in the oxygen/propane flame obviously not copper.

So far I have recovered 880 grams in addition to the 2.10 lbs in the jar below which have a strange color. Getting excited with anticipation to refine this lot.

The cornflake silver was previously processed in nitric then cemented with copper then melted into a bar without any further processing towards refining until this morning when the bar was melted into cornflakes to be refined with the 880 grams.


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## kmggold (May 25, 2010)

Very interesting thread. We get hundreds of pounds of electrical contacts from industrial sources. All are solid silver backed onto a copper buss bar or similar. Most are alloyed silver - 30% - 99% pure.
Copper does not present a challenge for wet refining or for melting. Ferrous material will contaminate the crucible but is not a problem for "wet" refining procedures.
What does present a challenge in traditional melting of the contacts, are contacts that are alloyed with cadmium, cobalt, and tungsten.
Cobalt and tungsten will not melt, while cadmium is a hazardous material.
Melting silver alloyed with cadmium is toxic and very harmful if fumes are breathed in. So be sure to take precautions.
All contacts, including the ones alloyed with W, Co, and Cd, can be melted in a vacuum furnace at additional expense. 
Silver can be recovered by getting rid of the Cd, Co, and W using a very strong base such as sodium hydroxide. 
The least amount of recovery in the Co alloys and the most amount of recovery in the W alloys. 
More information on electrical contacts can be found at KMG Gold, http://www.kmggold.com/canadian-payout-cash-lots.cfm
Good luck!


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## Chumbawamba (May 26, 2010)

At the risk of asking a question that can be answered with lots and lots of searching that I don't currently have time for, what does "incineration" entail? Does one put the material into a high temperature oven? Ran through a furnace or kiln? Hitting it with a blowtorch? I often see people calling for the incineration of such and such before the next step, but I'm always unsure what this means exactly.

What do you all make of the magnetic contacts? Are those ones which are possibly alloyed with cobalt or tungsten?


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## Palladium (May 26, 2010)

kmggold said:


> More information on electrical contacts can be found at KMG Gold, http://www.kmggold.com/canadian-payout-cash-lots.cfm
> Good luck!



I didn't find anything about contacts listed there, hugh !!

You have made three posts and everyone has a link back to your website.
Steve has already pointed out your violation of the forum rules in this respect. It seems that you have added some pertinent information in your post so it's not a total ad to say i guess. If you want to advertise any of your services here on the forum there are places set aside for this and it is free to post there. If you want to put it in your signature line that would work to, if you’re posting useful information it will follow you everywhere you post. Please don't use that link in another open board post.


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## butcher (May 26, 2010)

Incineration, with fire bringing metal to a red glow, but not melting it,
Sulfide’s are the last chemical to evaporate, when incinerating we are driving off these acids, from the metal, and oxidizing the metals, lets say we want to roast a rock to get the gold out and this rock was chalcopyrite a copper iron ore with gold locked up in it,
First we need to finely divide the rock crush to fine powder, now this rock not only contained the metals but also acids that formed them to make the copper iron sulfide salts this rock is made of,
CuFeS2 chalcopyrite ore
Say we put fire to this rock in lots of air to oxidize it
3CUFeS2 + 18O ---heat---> Cu2S + 3FeSO4 + CuSO4 + SO2
Here we don’t have it hot enough yet we still have copper sulfide and have also made copper and iron sulfate with the sulfur dioxide gas, we need more heat in open air,
At about 600 degrees the iron sulfate will start to decompose,
Cu2S + 2FeSO4 + 6O ---heat 600deg--> 2CuSO4 + Fe2O3 + SO3
Now we have copper sulfate and iron oxides and sulfur trioxide gas,
Still not hot enough we keep the heat on in open air, 
Till we get to 700 degrees C and hold this temp for a while in lots of air or oxygen,
Until we drive off the sulfates to get copper oxides and iron oxides, now these will be easy for our new acid to dissolve, (the old sulfide from sulfuric acid that made the rock will not stop us now), this will also unlock our gold from its bonds,
Even ore in a melt will need to be roasted (like an assay) , the sulfide in the ore may make a sulfate in the melt with other metals and keep your gold from you being able to get it,
So incinerate means to burn or roast your ore or material it is to rid acid and convert metals and without this tool you are losing your gold.

Others can give better answers but here is mine.


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## Harold_V (May 27, 2010)

butcher said:


> Others can give better answers but here is mine.


You did just fine. The only thing I'd add is that when incinerating recovered values, you not only eliminate unwanted acids and other chemicals, but you also eliminate carbonaceous materials, including oils, which are often troublesome in causing precipitated gold to stick to vessels, or to float. Incineration is the magic bullet of refining. 

Harold


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## Chumbawamba (May 27, 2010)

Butcher, thanks for that excellent explanation!

I need more time to read. If only I had some


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## jaun (Jun 5, 2010)

Here’s how I process these contact points.

First I cut off the points with a side cutter, just below the points. I then put them in AR, the AR dissolves the back plate, and leaves only the silver points.

You then dissolve the points in nitric, and cement with copper.
That is the fastest way to process these materials, tried and tested by me for 15 years, and used by all refiners I know.

The large breakers with the square silver contacts (or round) on the bass bars, you heat with a torch to red until they come loose, and you just flick them off with a thin steel rod or screwdriver. And then process with nitric (boil), and cement with copper.
8)


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## Oz (Jun 5, 2010)

If you put silver in AR you will form a silver chloride pacification layer while you digest your “back plates”. It sounds as though you are getting nitric to penetrate that layer on the remaining portions of the contacts but what of the silver chloride formed that ends up as particulate in your AR digestion or nitric digestion? If you do not address that issue you are throwing out silver.


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## jaun (Jun 5, 2010)

Yes a pacification layer forms, it makes the points a black colour. 
Hot nitric penetrates the layer easily, no problem. All that’s left after the nitric boil, is verry thin gray foils (the silver Cl layers). You just decant or filter that out. Its so thin (like gold foils) I don’t even bother refining them. (You can put it in your silver stockpot).

Silver chloride never particulate in my AR digestion. It’s just clean black points that’s left.


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