Trash or treasure

[maltfoudy]

well the snow is almost gone, so i will be venturing outside to start cleaning up some of my stock piles have a few questions,gonna try to streamline my sorting practices

IC Chips i have alot of ceramic ic's some with a white/gray ribbon that runs through them and they come apart easy,some are just solid ceramic through out, my question is, is it worth seperating these 2 different types of IC's or not.

also white porc. Beckman ic's,some orange ic's

Transistors or at least what i think are transistors,stainless metal cap,gold ring around the bottom with 2-10 gold wires also have some that do not have the gold ring or wires,is there anything in the ones without?

best way to test old boards to see if the soldier runs are silver or not? I have a silver test acid made of nitric and potassium dichromate but do not know what reaction/color to look for.


mercury switchs,i have a few wetted mecury switchs that i have laid to the side,is there a market for these.

 

[Harold_V]

I have a silver test acid made of nitric and potassium dichromate but do not know what reaction/color to look for.

Blood red, and opaque.

Harold

 

[maltfoudy]

thanks harold,the solution looks like iodine color itself,when i put a drop on the solder runs it eats down to the copper under the silver and turns cloudy gray.like dulled silver,will this solution dissolve lead solder?

 

[Harold_V]

Being nitric, yes, it will dissolve solder, at least to some degree. It will also dissolve copper and copper alloys, so if you leave the solution on such a sample long enough, you'll slowly see a greenish color develop. A lot depends on what the base metal is as to the color you'll see develop. It's a good idea to do some testing on known materials so you become familiar with the developed colors. Do allow the tests to sit for several minutes, too, so you can see the changes I spoke of.

Any silver present will give an immediate reaction. If you have any doubts about what you're seeing, it isn't silver. Pretty simple.

With silver, the color that develops can be an indication of the purity of the silver. As the copper content increases, the red color is more subdued, and starts to shift towards a red/green color. Pure silver will be very deep blood red, as I said, and sterling isn't far behind, although as the test sits for a while, the color shifts somewhat. It should not be construed as an assay in any way, but it can be a good indicator of the presence of copper. Of course, you can also test with a drop of nitric acid if you have any doubts. The resulting solution will be green if you have copper or nickel present, but if the spot tested doesn't shift color drastically, and the metal itself turns a creamy light brown color, pretty good chance it's silver. You can add a little salt, or a drop of HCl to the spot to see if silver chloride develops.

Harold