# Silver from circuit breaker bars and contact point



## goldfinger3 (Oct 17, 2016)

So a while back at a local yard sale i ran across 2 boxes of roughly 50 circuit breakers. I have broken them all down and seperated them into catagories. You have some parts http://imgur.com/a/AUu0D that appear to be solid silver some have silver contact points (pads) and some of it is copper and silver braided wire had a almost yellow cast to it. From the research i have done the pads will be a copper/silver alloy since the silver would normally be to soft to take the repeated abuse of the breaker smacking together on engage. Does anyone here have experience on how to process these parts since they will contain copper/silver alloys?


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## kurtak (Oct 17, 2016)

If they are "circuit breakers" they will NOT be silver copper alloy - they will be silver tungsten & the silver tungsten is NOT an alloy - it is a matrix of silver & tungsten "sintered" under high pressure & heat

They run 30 - 40 % silver & the rest is the tungsten

I am talking about the actual points that make the contact when the switch is closed

the silver needs to be leached out of the tungsten matrix - to do this it is best to first de-solder the point from the bus bar it is soldered to - they then need to be boiled in nitric acid that is diluted with distilled water (you can not use tap water) how much you dilute the nitric will depend on the starting strength of your nitric 

the bus bars that the point is on will be copper & they may or may not have a thin silver plating on the copper

Also the wire will be copper that may or may not have a thin silver plating on the copper 

Here is another discussion about silver/tungsten points

:arrow: http://goldrefiningforum.com/phpBB3/viewtopic.php?f=50&t=23871&p=252313&hilit=tungsten#p252313

If they are contact points out of magnetic disconnects or relays then they will be an actual alloy that is high in silver & they are processed a bit different then the silver/tungsten points in that you don't want to actually boil them

Kurt


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## g_axelsson (Oct 17, 2016)

What I see on that picture is one copper wire, one copper breaker with (probably) silver contact point, two silver plated brass pieces and two silver plated brass pieces with silver contact points spot welded. Not a lot of silver.

Göran


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