gold plating on e-scrap

[smj]

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

 

[goldsilverpro]

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.

 

[franklynvoorhies]

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

 

[lazersteve]

Try this link:

Resizing Images

Steve

 

[franklynvoorhies]

ok i got program now the questions begin

 

[franklynvoorhies]

ok this is all gold yea?

 

[Barren Realms 007]

It would be nice to see the picture.

 

[lazersteve]

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

 

[franklynvoorhies]

ok can u see the pic?

 

[lazersteve]

Excellent.

Steve

 

[franklynvoorhies]

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?

 

[lazersteve]

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

 

[franklynvoorhies]

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?

 

[franklynvoorhies]

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.

 

[Oz]

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.

 

[g_axelsson]

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