motherboards

[patnor1011]

Here is update as promised on prices. Just spoke to my friend about that 3 types of PCBs as he selling them to refiners. Prices went down but very slightly.
1. was 95 czech koruna and now is 80 czech koruna which is 4,200.55$/ton
2. was 45 czech koruna and now is 40 czech koruna which is 2,103.53 $/ton
3. was 7 czech koruna and now is 3 czech koruna which is 157.68 $/ton

http://www.xe.com/ucc/ currency convert used.

This is what he is getting now.

 

[megacik]

nice to have fellow countryman onboard... not all of them are solid gold, only certain types, will try to find out what type is the best... where are you from? pm me in slovak...

You have PM.

By the way, Slovak corona(EURO from 1.1.2009) is very strong now....

 

[megacik]

I have thrown a small amount of these relay contacts(but before - with hammer I made a thin shim from it) to AP. For test purposes I´ve added also a little gold contacts from old VESA cards.


After 2 days:
- all the gold from the contacts of VESA cards are floating arround as I expected, but all of this thin shims are intact. They are the same as before, what kind of metal is not reacting in AP? Could it be pure gold, as we were thinking? Or something else?

 

[patnor1011]

Any pictures please?

 

[megacik]

Sorry for the quality. I will leave this working for a week and then I will post the results.

 

[lazersteve]

Your contact points may be gold plated silver. I've processed the points by melting together then using nitric to leave the gold. The video is on my website under the Silver section: Separating Silver from Gold.

Steve

 

[megacik]

I thought so about a silver, but I already tested gold flake with gold tester, and it is still showing 18-24 carat gold in the middle. Also the flake was golden-yellow inside, after I hammered it....so now I am not sure, if it is silver or not.

Thank you for the video, sometimes I´ll try it. But before I have to buy chemicals. Here in Slovakia I can´t find nothing except HCL and H2O2

 

[qst42know]

It would be difficult to hammer a gold plated contact in such a way as to expose the center. Gold is notorious for being able to be hammered extremely thin and still give the appearance of being solid. Even cutting with nippers would likely just stretch the gold layer and still not expose the core.

 

[megacik]

That sounds to me more interesting, that I expected, because I did these flakes with hammer very easily. I hit 2-3 times and from small button became thin "cornflake"

 

[goldsilverpro]

Silver also flattens very easily. Also, if you cut the point, and the point was gold over silver (common), the gold would smear over the cut. The way I would test it would be to file across the point and examine the color with an eye loupe. If you see white, silver is under the gold. Put a drop of nitric in the notch. After about 10-15 seconds, add a drop of HCl or salt water. A white precipitate says that it is silver.

You can first file off a little of the point and then cut off the whole point with a knife and put it into a small amount of 50/50 nitric. Add a little heat. If all that remains is a gold shell, silver was present. You can also test the solution for silver with HCl or salt water.

How did you determine the point to be 18-24K? Touchstone? Electronic gold tester? Both are unreliable if the gold smeared over the cut when you cut into it.

 

[megacik]

I have electronic pen tester for gold, I am testing jewelery with it.

I have tested "button" before I removed it from relay and I thought It is only plated gold, but then....I made a flake from it and tested again in the middle and that was the same. I threw it into AP a there was no change.


They are not producing anymore, they were used in old switchboards(1989 and later, but most of them are still working), usualy are selling for 0,5 USD - 2 USD, but some stores are selling it for 10 USD e.g.
http://www.elida.cz/cze/elida/scripts/detailzbozi.aspx?Kod=0040110995

But as I said, we will see after testing

 

[megacik]

After a week:

- there were 2 types of contacts, the first are now black colour(silver?), the second hasn´t changed after a week.

It is interesting, that all foils from VESA card has disolved in AP Is it usual?

 

[Oz]

Megacik,

Not knowing the details of your AP bath I would assume that you over oxidized the solution with too much H2O2. The gold is not lost and can be recovered with SMB or if you continue to use the bath for other fingers it will cement out as a fine black powder as your solution increases in Cu content.