# Testing Circuit Boards For Precious Metals - VIDEO



## kadriver (Dec 12, 2016)

Here is a short video (with narration) showing how I learned to test circuit boards for precious metals:

https://youtu.be/Y7YxSZnx2M0

Thanks!

kadriver


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## goldsilverpro (Dec 13, 2016)

Good video. The heat from the lightbulb and using the paper towel are good ideas. However, I'm not a big fan of the Schwerter's solution.

I know it's standard practice to use Schwerter's solution for testing silver. Although I usually had a bottle of it sitting around, I rarely used it. To me, about the only thing it's good for is silver alloys that are 90 percent Ag or better and sterling silver is about the only thing in that category. They say you can test 80 percent silver with it but there is often confusion. Below 80 percent. it's hard to see any red at all. Also, Schwerter's solution is virtually worthless for silver plate. The nitric cuts into the base metal and muddies the colors. Don't forget that red plus green equals brown. Also, red plus yellow plus blue can produce brown. On anything lower than about 85 percent silver alloy, there always seems to be confusion.

I learned a very simple, much more reliable test early on. It only is a go-no go test. It will only tell you whether silver is present or not. It will not tell you whether it is hi or lo grade. It works in the presence of highly colored copper or nickel solutions. It always works and there is never any doubt as to the results..

Simply put a drop of nitric acid of the surface of the suspected silver or in a notch filed into the object. Let it react for awhile and then add a drop of HCl. If a white cloud appears, silver is present. No white cloud, no silver. If testing the surface, the idea of warming it up from a lightbulb is a good one.


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## FrugalRefiner (Dec 13, 2016)

goldsilverpro said:


> The heat from the lightbulb and using the paper towel are good ideas.


I've always found the stain on a paper towel from Schwerter's to be more reliable than how the drop looks on the piece being tested. Sometimes on a suspect piece the drop can look sort of an orange red, but when blotted off with a paper towel the stain quickly turned blue. With silver, the stain on the paper towel will stay dark blood red.

Dave


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## kadriver (Dec 16, 2016)

I bought some potassium dichromate and made my own schwerters.

I increased the concentration of the dichromate and found it works great even on lower silver alloys.

Ive also found that schwerters goes bad over time. I add some new crystals to my homemade solution every few months, along with a squirt of nitric.

I must give the nitric/HCl test a try, i've never seen it before.

But I have seen the silver chloride form on a touchstone when I tested a gold plated silver ring that I thought was karat gold.

Cheers!

kadriver (Kevin)


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