# Silver in AR



## Marcel (Nov 6, 2012)

I have tried to dissolve wires from potentiometers, which appeared to be silver to me. I started with diluted nirtic (around 15%-20%) but it had no effect on the wires, then I went to 53%, becuase I only had 53% nitric availbale but he wires would not dissolve.
So I ended by adding HCl to create AR and the solution started to get hot and dissolve the metal.
Now I have done a test with SC, sinse I was not sure wheter this was really silver and the result of the deep (Hulk)green solution was negative. 
I have no sediments whatsoever in the solution.
My question now is: Can I cement with copper directly though I may have chlorines from the HCl in my solution, or do I have to go some extra way?

Just for info: This is the component and the wire is inside. It is wrapped around some sort of oily plastic.. Usually it is made of silver in this type of device.






http://en.wikipedia.org/wiki/Potentiometer


----------



## butcher (Nov 6, 2012)

Yes, you can cement on copper as long as solution is at least somewhat acidic (which your solution should be), anything in the reactivity series below copper would cement out of solution. Basically if any values were involved they should cement out.


----------



## qst42know (Nov 6, 2012)

Have you checked the manufacturers data sheet for the parts you are working on?


----------



## nickvc (Nov 7, 2012)

Marcel as you used AR and have no sediment, silver chloride, I believe your material certainly wasnt silver, have you tested the solution with stannous? If you have any values the test should tell you.


----------



## g_axelsson (Nov 7, 2012)

There is only one place in a potentiometer that would benefit of being silver, the slider that runs along the resistance wire. By definition the wire that runs along in a loop has to have a large resistance and silver is the best conducting metal of them all.

The only metals I've found in potentiometers are silver and goldplated copper alloys for the slider and base metal resistance wires.

/Göran


----------



## butcher (Nov 7, 2012)

Sometimes the potentiometers can contain gold or PGM,s, resistance wire can be made from several metals which have resistance, and can handle the heat involved, carbon is also used as it makes good resistors.

http://www.google.com/#hl=en&tbo=d&rlz=1R2RNQN_enUS457&spell=1&q=gold+platinum+group+metals+in+resistors+and+potentiometers&sa=X&psj=1&ei=z0WaUJO-LsKRiQLlnoDoDA&ved=0CCoQvwUoAA&bav=on.2,or.r_gc.r_pw.&fp=877e95b38227681d&bpcl=37643589&biw=1024&bih=539



I have made my own variable resistors for controlling the speed of direct current motors (DC motor with brushes), by wrapping stainless steel (wire feed) welding wire around a porcelain tube, and using a stainless steel hose clamp used for the wiper to adjust resistance.

I have also used Nichrome heater wire; this also works very well when making your own power resistors.

This adjustable resistor can also be used to adjust voltage of an electrolytic cell (parallel circuit), or limit current of the cell (series), although the light bulb in series with your cell is a much better regulator for current, as it can act as a short circuit protection device, and the lamp is also a good visual indicator of current of your electrolytic cell.

Here an experiment to try if you have an ohm meter handy, scratch a thick long mark on paper with a pencil rubbing the pencil back and forth over this line many times, to deposit a thick layer of graphite carbon on the line, now take your ohm meter on ohms scale and touch the leads to the ends of this carbon mark, now slide the meter leads closer, then further apart, watching your ohmmeter scale, see how the resistance in ohms changes, see you have just made a potentiometer, or variable resistor.


----------



## goldsilverpro (Nov 12, 2012)

goldonline said:


> We are the American Gold & Silver Exchange, and we buy, sell and trade all sorts of wonderful things.



If you want to advertise your company, do it in the Refiners, Buyers, Assayers, etc. Category.
http://www.goldrefiningforum.com/phpBB3/viewforum.php?f=84


----------



## AndyWilliams (Nov 12, 2012)

goldonline said:


> We are the American Gold & Silver Exchange, and we buy, sell and trade all sorts of wonderful things.



Hmmm, silly me, joined as a singular person. So what names can we expect "we" to be?


----------



## Geo (Nov 12, 2012)

ive found the round pots have gold plated legs.


----------

