# gold plating on e-scrap



## smj (Sep 1, 2010)

Hi guys, i was wondering what type of plating solution was/is used for plating fingers & pins.


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## goldsilverpro (Sep 1, 2010)

smj said:


> Hi guys, i was wondering what type of plating solution was/is used for plating fingers & pins.



It usually contains potassium gold cyanide (4 to 8 g/l of gold), citric acid, potassium citrate, and cobalt sulfate (or, nickel sulfate). If I remember right, the amount of cobalt sulfate runs about .12 -.50 g/l. The total amount of citric acid and potassium citrate is about 130 g/l, in the right ratio to give a pH of 4.2 (I remember that it was close to a 1:1 ratio of the 2 chemicals, but you should experiment a bit). Some manufacturers also add some EDTA. It uses platinized Ti or Ta anodes, a temp. of 70-120F, a CD of 10 asf, and deposits about .03-.04 g of gold/amp-min. The purity of the deposit is between 99.0% and 99.9% gold, depending on how much cobalt is added to the bath. The cobalt acts as a hardener. The bath should be constantly filtered. 

I haven't formulated this bath for about 35 years, but I think most everything I said is right - I can't remember anyone's name, but I'm good at remembering technical stuff. At that time, this bath was the main one used in the industry to plate fingers/pins. I doubt if things have changed much today.


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## franklynvoorhies (Sep 3, 2010)

i sure cant get a pic to load i fail =(


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## lazersteve (Sep 3, 2010)

Try this link:

Resizing Images

Steve


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## franklynvoorhies (Sep 5, 2010)

ok i got program now the questions begin


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## franklynvoorhies (Sep 5, 2010)

ok this is all gold yea?


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## Barren Realms 007 (Sep 5, 2010)

It would be nice to see the picture.


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## lazersteve (Sep 5, 2010)

franklynvoorhies said:


> ok this is all gold yea?




You have to specify the entire path to the image typically like this:


```
[img]http://goldrecovery.us/images/goldbars.jpg[/img]
```

and here's how it displays when used without the 'code' tags:






If you want to upload the photo as an attachment just check the 'inline' check box after attaching the photo.

Steve


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## franklynvoorhies (Sep 5, 2010)

ok can u see the pic?


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## lazersteve (Sep 5, 2010)

Excellent.

Steve


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## franklynvoorhies (Sep 5, 2010)

so when i go to reocover from this board and others like it , i should remove as many pieces of plastic as possible right? and is this single board a good amout of gold?


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## lazersteve (Sep 5, 2010)

franklynvoorhies said:


> so when i go to reocover from this board and others like it , i should remove as many pieces of plastic as possible right? and is this single board a good amout of gold?



From the photo the board does not look to contain much gold at all. The yellow color you see is most likely just a yellow colored solder mask over the copper traces. 

Here's a close up of a similar type of motherboard with the mask scraped off:

Motherboard Solder Mask

The whole thread is a good read about solder masks and processing motherboards on a small scale.

Steve


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## franklynvoorhies (Sep 5, 2010)

thanks so much for your help, and i do apologize about repeating questions. i keep reading and reading and then i ask and get a response to a thread that answers all my questions,lol. i been reading the hoke but i is there a printer friendly version avail?


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## franklynvoorhies (Sep 5, 2010)

sad to learn its a mask, but the behind the ceramics is gold for sure? also, do the pci slots have gold? im not sure what all has worthwhile gold in it.


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## Oz (Sep 6, 2010)

Most card slots on motherboards do have a gold platting on the fingers but they are relatively low yield. Always use caution and a good respirator if disassembling them as most gold plated copper that needs to function as a spring typically contains beryllium which is rather hazardous to breath. 

Welcome to the forum.


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## g_axelsson (Sep 6, 2010)

I do not think that the PCI and ISA contacts contains any beryllium. The base metal isn't copper but brass and that is stiff enough to work like a spring.

But the PCI and ISA contacts are only plated on a small area and is low yield.

/Göran


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