Silver Recovery

**eesakiwi** · 12-12-2011, 05:27 PM

Originally Posted by miked

Gus, in the lower right corner is a small round disc. I found a similar one in a contact type item that seemed to be made of bake-a-lite type plastic. Because I was disassembling with a large hammer I don't know where it was positioned. I saved it so do you suppose it contains silver? Thanks for all that you contribute here, Mike.

I think you mean the relay from a fridge compressor.

The one in the bottom left corner has a silvery disc inside it.
I have seen a few of them, it looks like white/clear ceramic with a silvery tinge to the outside of it.
I haven't took much notice of it, they seem to replace the relay in the top right corner, which I rip the copper coil out of.

**gustavus** · 12-12-2011, 06:03 PM

Originally Posted by eesakiwi

I think you mean the relay from a fridge compressor.

The one in the bottom left corner has a silvery disc inside it.
I have seen a few of them, it looks like white/clear ceramic with a silvery tinge to the outside of it.
I haven't took much notice of it, they seem to replace the relay in the top right corner, which I rip the copper coil out of.

The disc is a thermo bi metal, two ,metals laminated together each has a different expansion rate, the one which expands first will pulling the other metal along with it. On cooling the lesser thermo active metal wants to return home, in doing so pulls the copper along for the ride resetting the contacts to complete the electrical connection.

Electric dryers all have several thermo disc's now depending on how thick the copper sheet is that was bonded will determine how many degrees are required to break the electrical connection. When the thermo disc cools the disc will snap back to its home position energizing the heating element.

You'll find these in space heaters, counter top coffee pots, inside microwave ovens, electric dryers, motor overload protectors, the list is endless

Different metals could be laminated together to make a thermo disc, I used copper and iron as an example. Some discs are meant to have closed contacts when cold while others will close when hot for example to start a fan for cooling or a pump to circulate cooling liquids.

The disc itself has no value that I know of, some may bear further investigation if the other metal is nickel. It is the small silver contacts your after to save.

This web site sell thermo switches, just to give you an idea of how many different types there are http://www.senasys.com/shop/?gclid=C...FUYUKgodwBevBA