Fever
Well-known member
And.... The best method to refine?
Below are a set of photos I took of some of my "naked" memory and cell phone circuit boards. My questions are these, and Steve, perhaps you can best answer this:
1. In the first picture, you see a memory module with gold fingers and no other apparent gold on the chip surface. I will only harvest the gold fingers on this module, because there is no indication of any gold races under the surface of the sealant. They will be cut clean with a bandsaw. Makes sense, right?
2. In the second picture, you see a memory module with gold fingers and lots of other exposed areas with gold on the surface. I will not cut these fingers off, because I suspect that the entire substrate races of this module may be gold plated, as apparently evidenced by the large amount of gold across the surface. My plan is to process this module whole in the acid bath, and harvest the gold flake after the base metals are digested. Makes sense, or am I far too optimistic that there is more gold here (sub-surface) than meets the eye?
3. In the third picture, you see a couple of cell phone circuit boards quite rich in gold across most of the surface. I also will not cut these gold plated areas off of these boards because I suspect that their entire substrate races may also be gold plated. I could process these whole as well, and harvest the remaining gold flakes after the base metals have dissolved into solution.
I have scratched through the surface sealant above the races of many of these boards, and some are clearly copper underneath, while others seem to shine golden just like the exposed gold plated areas. I view them through a low-power microscope for definition and a clearer visual.
So, is it uncommon to have the races completely plated in gold, even if they only exposed the contact points during the sealing of the surface? The older the boards are, the more likely they are plated across the entire surface right?
Thanks for any clarification and education......
Fever
Below are a set of photos I took of some of my "naked" memory and cell phone circuit boards. My questions are these, and Steve, perhaps you can best answer this:
1. In the first picture, you see a memory module with gold fingers and no other apparent gold on the chip surface. I will only harvest the gold fingers on this module, because there is no indication of any gold races under the surface of the sealant. They will be cut clean with a bandsaw. Makes sense, right?
2. In the second picture, you see a memory module with gold fingers and lots of other exposed areas with gold on the surface. I will not cut these fingers off, because I suspect that the entire substrate races of this module may be gold plated, as apparently evidenced by the large amount of gold across the surface. My plan is to process this module whole in the acid bath, and harvest the gold flake after the base metals are digested. Makes sense, or am I far too optimistic that there is more gold here (sub-surface) than meets the eye?
3. In the third picture, you see a couple of cell phone circuit boards quite rich in gold across most of the surface. I also will not cut these gold plated areas off of these boards because I suspect that their entire substrate races may also be gold plated. I could process these whole as well, and harvest the remaining gold flakes after the base metals have dissolved into solution.
I have scratched through the surface sealant above the races of many of these boards, and some are clearly copper underneath, while others seem to shine golden just like the exposed gold plated areas. I view them through a low-power microscope for definition and a clearer visual.
So, is it uncommon to have the races completely plated in gold, even if they only exposed the contact points during the sealing of the surface? The older the boards are, the more likely they are plated across the entire surface right?
Thanks for any clarification and education......
Fever
