Process populated boards?

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ibexlatham

New member
Joined
Dec 20, 2019
Messages
4
How would you process these boards?

I tried the Acid and Peroxide method and failed miserably. After reading the board I realize the grey sludge I was getting that plugged my filters was an issue with the solution, but I have some other issues to get past too.

First off, these boards are about 9x7 inches, they are populated with lots of tiny chips and larger components. There’s plenty of tiny gold “rings” and dots (about 1mm-2mm in diameter) and some gold fingers. Wherever there is a component there is gold plating under the solder. I have about 100 of them for free and regularly get more in to test from work. We just throw them in the scrap bin and pay the scrap guy to take them.

When I initially tried it I took 3 boards and cut them up into small 2x2 inch pieces and put them in the AP solution and let it sit. When I tried to filter it, the filter immediately plugged (because of the grey sludge and small chips). After trying to rinse and filter it outside in 30 degree temps for an hour I got sick of it and slowly dumped in baking soda to neutralize it all and dumped it into a bucket.


So my question - how would you process these?

Each of those gold “rings” has a pin from a connector or component going through it.

When I process it in the AP soliton all the small chips fall off and make it harder to filter.

Would I be better off gently torching them to depopulate them first and I’m left with just the boards, solder, and gold plating on them?

Should I cut them up first, or just get a large container and put them in there whole?

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Study the forum to learn what is worth processing and what is not.

Pile the stuff up until you learn what to do with it safely.
 
jimdoc said:
Study the forum to learn what is worth processing and what is not.

Pile the stuff up until you learn what to do with it safely.

I guess that’s the problem I’ve run into in a nut shell. I’ve been researching this site and other for about a month, trying to figure out if it’s even worth it.

I was trying to run a small scale test to see if my estimate is correct. Rough guess is each board contains about the same amount of gold foils as 2-3 pieces of RAM. Right now I’ve got 100+ of these waiting to get thrown in the garbage at work, and I get about 5-10 more per month, all free scrap. After the small test if it turns out I’m not getting close to my estimate then I can put the idea on the back burner and work on other projects and try to find something more worthwhile.

I was thinking about it and I realized depopulating them as much as possible would be best, and working on the grey sludge problem would solve my filtering issues.

But then I’m left with the size issue... if I cut them up I’ll cut a lot of the foils into even smaller pieces, and be left with sediment from the boards too (not to mention the time to cut them up with tin snips). But leaving them intact means a larger container and more AP.
 
Trying to process whole boards will not work. I sell my boards, as do a lot of others here.
Those boards I would just sell, not even think about processing.

You can save all the gold fingers until you have enough to process.

If you get them for free, just save them up and study the forum while it is too cold outside.
 
The tiny Gold rings and plating under the components is called ENIG, it is an incredibly thin Gold coating and is generally not worth recovering.

I would definitely do a test on those fingers too, good chance that they are just ENIG, which would make the whole board basically not worth processing . . .

https://www.youtube.com/watch?v=iav_KH0PEZY

Best case scenario is that each of those boards has about 20c of Gold on them, and that requires processing the ICs which is a completely different beast.
 
Thanks for the replies, I see where I went wrong.

I saw gold, assumed it was worthwhile, and then researched all the processes and everything else before figuring out if it was even worth it.

Basically I missed step 1.
 
"I saw gold, assumed it was worthwhile, and then researched all the processes
and everything else before figuring out if it was even worth it. "

Said every newbie that has come to the forum - INCLUDING ME!! :lol:

We see the shiny gold and become convinced we have a gold mine!!
THEN we figure out what we really have. Some by trial and error
and some by listening to the sage advice of those who have trod
this path to "quick riches" before. 8)
 
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