Did I hit the jackpot?

[Kevin Mackin]

Recently came into possession of these old circuit boards. The amount of gold on them is amazing... One looks completely covered in it. Are the pins on these ever solid gold? Are there other PMs I should be watching for?

 

[Kevin Mackin]

Recently came into possession of these old circuit boards. The amount of gold on them is amazing... One looks completely covered in it. Are the pins on these ever solid gold? Are there other PMs I should be watching for?

 

[GoIdman]

Recently came into possession of these old circuit boards. The amount of gold on them is amazing... One looks completely covered in it. Are the pins on these ever solid gold? Are there other PMs I should be watching for?

Hi, where are those circuit boards from? Usually the pins are not solid gold (may be in some very unique cases) they are plated, which case its age will determine the thickness of the plating (the older the board is, the thicker the plating gets).

Pete

 

[Kevin Mackin]

Hi, where are those circuit boards from? Usually the pins are not solid gold (may be in some very unique cases) they are plated, which case its age will determine the thickness of the plating (the older the board is, the thicker the plating gets).

Pete

A guy in the building I live in collected them from old Ampex CNC machines... They're from the 80's I think. He's got 100 pounds of the stuff he says, some has palladium and platinum. He doesn't want to mess with it and said he'd split it all 50/50

 

[Kevin Mackin]

Hi, where are those circuit boards from? Usually the pins are not solid gold (may be in some very unique cases) they are plated, which case its age will determine the thickness of the plating (the older the board is, the thicker the plating gets).

Pete

 

[Kevin Mackin]

Looks solid all the way through to me??

 

[Spaceships]

Looks like older enterprise hardware boards to me. If you look at the below:

Blue circle - look for gold in all those types.
Red - look for Palladium and poss Platinum. Check one of each to see before trying to dissolve the lot. Some of these do, some don't but the older it is the more likely it is that they have PGMs.
Grey- if it's heavy when you cut it off, i.e. it doesn't feel light and hollow then it could be Silver/Tantalum.
Enjoy

 

[kurtak]

Red - look for Palladium and poss Platinum

The one that are a burgundy color & kidney shaped are silver mica capacitors no PGMs

Kurt

 

[patnor1011]

Pins may look solid all the way through but unless it is some experimental, space, prototype, military stuff or very old soviet stuff they will not be solid gold. Even though some Soviet and friendly countries stuff sometimes contained 14-18k gold contacts in some relays I do not think I ever seen solid gold pin in electronics.

 

[kurtak]

Looks solid all the way through to me??

They are ether gold plated brass - or - gold plated phosphor bronze

If they are the gold plated phosphor bronze pins & you dissolve the bronze in nitric acid to recover the gold foils you will end up with a real mess because the tin in the bronze will turn into a bunch of meta stannic acid (tin paste) mixed in with your foils

Kurt

 

[kurtak]

One looks completely covered in it

The board that is completely covered with gold plating on the back is plated with what is called ENIG plating

ENIG plating is VERY thin - if you dissolve the copper under the plating away the plating is so thin it will be like dust not actual foils --- in other words - though there is a large surface area of plating there is VERY LITTLE gold

Kurt

 

[Spaceships]

The one that are a burgundy color & kidney shaped are silver mica capacitors no PGMs

Kurt

Cheers Kurt. Ive seen a few random ones that do but you're 100% on that most are silver.

 

[kurtak]

Cheers Kurt. Ive seen a few random ones that do but you're 100% on that most are silver.

Per the bold print - interesting - over the years I have processed probably around a 5 gallon bucket of those (coffee can full at a time) & have never found any PGMs

Best way to process them is to incinerate them - ball mill - magnetic separate out the iron crimps that crimp the mica sheets together - then smelt - I add some silver cement to the smelt as collector metal in the smelt

Kurt

 

[cejohnsonsr1]

Looks solid all the way through to me??

No

 

[Proffshuggarn]

Looks solid all the way through to me??

Conclusion: Try to dissolve a pin, it should give you an answer immediately whether they are solid or plated.
I’ll pass my opinion, cause both suggestions are possible in my head
/Dennis

 

[Christian333]

Yellow: LED-Light Emitting Diode, potential for one solid gold bond wire and silver plated anode/cathode.
Red: Resistor network, potential for silver and PGMs, palladium and platinum most common, plated to the ceramic substrate.
White: TO-92 package style transistor, potential for 2 solid gold bond wires, precious metal plated substrate and micro chip die braze.
Orange: Axial mount resistor, rare chance for gold plated end caps and precious metal plated to the ceramic substrate.
Blue: Glass diode, potential for precious metal point bond. Solid gold and platinum alloys are common.
Purple: DIP-Dual Inline Pin array, IC-Intergrated Circuit, same potential as TO-92, one bond wire per lead.
Green: Epoxy coated MLCC-Multi Layer Ceramic Capacitor, potential for silver and palladium.

Janie

 

[Golddigger76]

Yellow: LED-Light Emitting Diode, potential for one solid gold bond wire and silver plated anode/cathode.
Red: Resistor network, potential for silver and PGMs, palladium and platinum most common, plated to the ceramic substrate.
White: TO-92 package style transistor, potential for 2 solid gold bond wires, precious metal plated substrate and micro chip die braze.
Orange: Axial mount resistor, rare chance for gold plated end caps and precious metal plated to the ceramic substrate.
Blue: Glass diode, potential for precious metal point bond. Solid gold and platinum alloys are common.
Purple: DIP-Dual Inline Pin array, IC-Intergrated Circuit, same potential as TO-92, one bond wire per lead.
Green: Epoxy coated MLCC-Multi Layer Ceramic Capacitor, potential for silver and palladium.

Janie

Janie has tested more components than anyone else that I have ever known, take the information Janine posted to the bank like it's fresh from the mint $100 dollar bills, it's spot on !!!

 

[Golddigger76]

I really like to refine the old resistor networks that are silver/palladium alloy printed on a white ceramic substrate, I have a huge batch to do soon that came from old organs.
Not huge returns but fun to refine.

 

[Alondro]

The board that is completely covered with gold plating on the back is plated with what is called ENIG plating

ENIG plating is VERY thin - if you dissolve the copper under the plating away the plating is so thin it will be like dust not actual foils --- in other words - though there is a large surface area of plating there is VERY LITTLE gold

Kurt

It's thin, but you're also dealing with a HUGE surface area on a board like that, so it's definitely worth processing. The gold content there will certainly be higher than for modern plated pins.

The pale green board at the bottom of the first picture I recognize as likely coming from old scientific equipment, probably from Germany. I got several like it from an old spectrometer made in 1985. All the traces are gold plated under the resin coating, and it's pretty thick too! At least as thick as the plating on pins of that era.

 

[GoIdman]

Looks solid all the way through to me??

They are most deffinitely not. I have a relatively large batch of pins recovered from automation equipments, and they are all plated stuff. But i might be wrong in this case.

If you had medical equipment boards, those could have been solid gold pins since critical life support equipment cannot fail, therefore the construction and functionality depends on solid connections. This is mostly why medical equipment is very expensive nowadays as it was 50 years ago as well.

You can always test 1 pin in a test tube with some acid to see what happens.

Be safe

Pete.