Milling silver contacts off

[etack]

Has anyone ever done this. I have lots of contacts on buss bars and I want to mill off the silver contact. I believe this will get the silver quicker and more efficient than sweating off with a torch.

The contacts are all Ag/x NOT W/Ag contacts.

I am looking for reasons that this would not work. My thinking is that I could put them in a vice and make a pass on them and mill them off and collect the chips. I think I could do a lot more an hour than I could with a torch. The mill is a little mill that will/has only been used for this.

Also some are Sn coated would it be wise to remove the Sn first or soak them in HCl after I mill them.

Eric

 

[solar_plasma]

Be sure to mill them to whole noodles. Any dust would be nasty, since silver contacts might contain cadmium.

 

[etack]

Thanks solar they were XRF and they contain no Cd.

These are middle size contacts about 11/16in or 17.5mm in diameter.

What is "whole noodles"

I don't think dust would be a problem with a slow spindle speed and a large cutter.

If I mill these off the Cu would be 1# also that is another (+) too.

Eric

 

[solar_plasma]

What is "whole noodles"


Eric

:lol: I meant something like this (what is the correct word?):

https://www.google.de/search?hl=de&....7.0....0...1ac.1.53.img..0.9.651.tc_HNYrGqPs

 

[etack]

Those are chips to me.

Eric

 

[kurtak]

Eric

If you have &/or get a lot of these larger type points it might be worth your while to put a set up like I have together for sweeting the points off the buss bars

Yesterday - about the same time you posted your question here I was actually running a batch & had I known I could have taken some pics of it actually in work - but these pics of the set up will have to do

What I do is put the bus bar/points in my turkey fryer/barrel incinerator (25gallon barrel with a turkey fryer burner in it) inside of which sets the stainless steel kettle - I then line the bottom of the kettle with the bus bar/points & turn the turkey fryer burner on full blast & give it about 20 minutes to come up to temp --- when the bottom of the kettle gets a dull red hot which takes about 10 minutes then about another 10 minutes for the bus bar/points to pre-heat --- each batch after the first batch only takes about 10 minutes as the kettle & incinerator are already hot

After the bus bar/points have had a few minute to preheat I then use the weed burner torch with flame blowing down on top of the bus bar/points till they get glowing red hot - pull the kettle out & give it a real good vigorous shaking & the points fall off the bus bars --- I then dump it in the big stainless steel pain for cooling

You want to sort them & do them in batches based on bus bar size/mass so they heat evenly - if you do them mixed (large mass with small mass) the smaller mass ones will actually start to melt down before the large mass ones come up to temp for the solder to melt

yesterdays harvest was a 3 batch run (based on bus bar mass) & only took me about an hour to run (including the start up time)

You need to do this out side with the wind to your back & as well as ware a respirator (or under a good fume hood & ware a respirator) do to the cadmium in the solder

I get about 80 - 90% of my silver from doing contact points ( about 60 lbs silver so far this year) which is why I built this system - its a real time saver over trying to sweat points off with a torch

Kurt

 

[etack]

That is pretty cool setup you have. The contacts you have are small and the amount of base metal is not that large also. The contacts that I get have a large buss bar attach to them. they weigh 50-260g each in Cu. My thinking is that they are all flat they all have straight sides (easy to put into a vice) and all the same thickness too. I have around 260# of these and more coming in every month too.

I also don't want to lose any silver in the way of soler of melting. Being able to sell them as 1# Cu is also a plus too.

I think that I will just get the mill and see how it goes if it work great if not I will sell the mill.

Eric

 

[kurtak]

That is pretty cool setup you have. The contacts you have are small and the amount of base metal is not that large also. The contacts that I get have a large buss bar attach to them. they weigh 50-260g each in Cu.

Eric

Eric

Actually the bus bars pictured in my cooling pan are about the same size as what you show in your pic - the ones on the left are about 210 gr & the smallest ones on the right are about 45 gr - you can't really read the scale that well but that's 1.2 lbs points on the scale (not gr or oz ) that's actual weight of the points (container was tare adjusted on scale before adding points) --- there is about 12 lbs copper in the cooling pan

Normally I will wait till I have a larger amount to run in the sweat off set up but I am getting ready to pour anode bars for my next silver cell run --- I pour 2 lb anode bars & I had 11 lbs silver to melt so I needed another lb silver to make that sixth bar

It doesn't happen very often but I have had contactors (magnetic disconnects) come in that have had contact point pads on the bus bars that weighted right at 1 ozt per point pad with 12 pads per contactor

Anyway - that's a real nice stash of large contact points you have

The milling idea is not a bad idea - just not sure if the time to mill (& expense of mill) will justify the up grade of #1 copper & silver recovered from solder

As a heads up - I could have done 2 -3 times in the same time the other day if I had more to do (there was room for more in each of the three batches I did) I just did this small bunch because I needed the extra lb of silver to pour that sixth anode bar

Kurt