Dang it was a long post. Not looking forward to re doing that. 
Partially plated pins won't disolve
- Thread starter Rreyes097
- Start date
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What did I do or say to indicate that I'm in a hurry to everybody? I know it may seem I'm in a hurry but I assure you that I am not. It may look like I'm in a hurry because I've been devoting a lot of time to the gold recovery hobby. But I'm not, in my humble opinion. I only ever have two projects going at any one time and one of those projects normally is something like AP where it's going to take a while and I don't have to mess with it constantly. The only reason why I ask the questions I asked was because after 3 days in the AP solution nothing happened not even the slightest of reactions and that has never happened to me.
The white residue was from a test run that I did with 10 to 15 pins with nitric acid and sulfuric acid. To see if they would attack the base metals. But sadly it only did a little bit. When I did use the AP solution I use an air bubbler and had it on there for roughly 3 days with no sign of reaction I again tried fresh AP and again nothing happened. So I guess I will have to decide whether I want to try AP again or nitric acid and distilled water. I asked these questions because I like to hear others opinions. I'm better at learning Hands-On and visually. But that doesn't mean I haven't done my due diligence and read and read and read this forum. In fact my wife gets mad because if I'm not in the garage working on my hobby I'm next to her on my phone reading about it.
So since I'm not in a hurry. I'll have to decide whether or not I want to do AP again. Does anybody want to weigh in on the subject nitrogen distilled water versus ap? I don't mind if it takes a long time. Should I try cutting each one in half?
The white residue was from a test run that I did with 10 to 15 pins with nitric acid and sulfuric acid. To see if they would attack the base metals. But sadly it only did a little bit. When I did use the AP solution I use an air bubbler and had it on there for roughly 3 days with no sign of reaction I again tried fresh AP and again nothing happened. So I guess I will have to decide whether I want to try AP again or nitric acid and distilled water. I asked these questions because I like to hear others opinions. I'm better at learning Hands-On and visually. But that doesn't mean I haven't done my due diligence and read and read and read this forum. In fact my wife gets mad because if I'm not in the garage working on my hobby I'm next to her on my phone reading about it.
So since I'm not in a hurry. I'll have to decide whether or not I want to do AP again. Does anybody want to weigh in on the subject nitrogen distilled water versus ap? I don't mind if it takes a long time. Should I try cutting each one in half?
jimdoc
Well-known member
Did you stir it once in a while? Or use an air bubbler?
AP is meant as an etching solution to get underneath the foils and cause them to release. It's not meant to dissolve whole materials that are thick like pins. You need a strainer to separate the pins from the bottom of the container they will set in with the ap solution. You will agitate the pins once or twice a day by picking the bucket up and spinning it back and forth by the handle and setting the container back into the ap solution and the foils will fall to the bottom of the 2nd container. You need an air bubbler. You need to add just a little weak H2O2 to get it started or some left over ap from a previous run. It can take several days for the etch to really take off. 7 days is the usual. After that it will work it's magic in about another week or so depending on solution strength and temperature. AIR IS IMPORTANT! I think a gallon of hcl will dissolve about 2.2 lbs of copper or around that. Don't dilute your hcl more than you have to unless working in BIG batches. Dilution will cause the copper chloride to drop out like above and slow things down. Using nitric with tin will create a tin nightmare. Forget that. It's like chasing your tail. Use ap like you are doing except make the above corrections with daily agitation and a strainer. On large batches use a 5 gallon bucket with holes drilled in the bottom small enough that the pins don't slip through, but large enough to allow the foils to break loose and wash through the holes settling in the bottom of another 5 gallon bucket. One bucket stacked inside another. The one on top having holes. Once all the foils are loose wash the pins and allow the rest of the foils to fall into the bottom bucket. Then strain the bottom bucket to recover the foils. Refining is the next step. This was recovery.
Thank you for the Birthday wishes gentlemen!
Thank you for the Birthday wishes gentlemen!
Martijn
Well-known member
Rreyes097 said:
AP = relaxed Rastafarian, no worries man
Nitric = formula 1 driver, had to get there yesterday!!
Regarding the commitment to this obsession: same here.. The wife is happy when I'm playing guitar near her and not working in the barn or reading the forum on the phone and sometimes even actually listen to her. :mrgreen:
You may not be seeing a reaction or color change going on in AP, because the AP is green and will stay green when enough HCL is present.
If white stuff forms, HCL is depleted. add more.
I'ts fine to do pins with AP, just as it's fine to do so with nitric(if there's no tin), with both methods you will dissolve 99,7 % of all the weight with acids to recover 0.3% of gold.
Enough time and cheap acid available? Waste management ok? Not a problem. But if you have piles of e-waste waiting to be processed and truckloads coming in every day? Not the most suitable methods in that case.
At a given point with AP, most the gold will have fallen off and all that's left is partially dissolved pins. maybe with the tiny flake of gold left. worth going after? That's the question you have to ask yourself continuously with this craft. Accept certain losses, rinse off and throw in the brass bin.
AP on PCB copper traces is faster and the best way to go for RAM fingers and such thin copper traces underneath the gold, yes, but not solely meant for that. It all depends on your personal situation and other factors.
I would save my nitric for silver and refining pm's, it's getting harder and harder to buy. Terrorist threat excuses.
The sulfuric cell works best o pins imo, but has higher risks, and needs constant attention. You can leave it alone for 15 minutes maybe, but then have to go back and stir a bit, or replace the pins. With AP, you can check as few times as once a week or even forget it for a month, nothing bad will happen.
choices choices.
kurtak
Well-known member
Rreyes097 said:
The following quotes from your different post's are what indicate that you are in a hurry
From your "first post"
from a couple other posts
As I & others have "tried" to tell you --- the AP process IS A VERY SLOW process :!: :!: :!:
Depending on the thickness of the gold plating it can take 3 - 4 days (& even LONGER) for the acid (in the AP process) to even get under the gold plating --- before the acid even STARTS to work on really dissolving the base metal --- then once it finally gets started --- it can take WEEKS to actually dissolve the base metals away to the point you have your "recovered" gold foils
Let me say that one more time ---------
In the AP process ----------
it can take 3 - 4 (or MORE) days BEFORE the AP process even STARTS to dissolve the base metal
THEN - once the base metal STARTS to dissolve - it can take WEEKS before the base metals is all dissolved to the point you have your recovered gold foils
The AP process is a VERY SLOW process - so slow you are not going to see an actual reaction - like you would see with nitric or AR
That is what EVERYONE has tried to tell you :!: :!: :!:
Do you understand :?: :?: :?:
Kurt
kurtak
Well-known member
Rreyes097
I didn't mean to be hard on you (my last post) it's just that you are clearly not listening to what EVERYONE has been trying to tell you
3-4 days is not enough time
Kurt
I didn't mean to be hard on you (my last post) it's just that you are clearly not listening to what EVERYONE has been trying to tell you
3-4 days is not enough time
Kurt
I clearly understand and hear you all. I just have never had this happen.
Topher_osAUrus
Well-known member
cosmetal said:
Yes, conformal coating is done to get electronics IP rated (water/dust). . This can be as simple as acrylic (clear fingernail polish/clearcoat) or potting compounds. Circuits dont like water. It can bridge small gaps in pins and short out something rather quickly, or it can be slow and steady, essentially electrolysing the trace
Yes, roasting should also be done. ..but, uh, maybe not so much with plastics, eh. The acrylic would burn off quick enough (I imagine).
kurtak said:
....so... what you're tryin to say is, I need a bigger bubbler? :wink:
-that was a joke-
(Not necessarily a funny one)
Edit to add more context beyond being a not so funny fella
(This is why I dont log on when i read, cant help myself!)
They aren't in any plastic anymore.
Martijn
Well-known member
Topher_osAUrus said:
Yes it was :lol: :lol:
And he was asking about gold plated parts for wear and tear resistance, so the contact points. Not the pcb traces with components as i understood. Those will be ENIG plated at best, right? Ì'll leave those in for the big copper scrap refiners.
IP rating is to indicate how big an object can be inserted in the gaps of the housing of an electrical device and how watertight said housing is.
The boards are coated to prevent water damage and corrosion to have a greater reliabity.
Just me nitpicking... :wink:
Topher wrote:
"Yes, conformal coating is done to get electronics IP rated (water/dust). . This can be as simple as acrylic (clear fingernail polish/clearcoat) or potting compounds. Circuits dont like water. It can bridge small gaps in pins and short out something rather quickly, or it can be slow and steady, essentially electrolysing the trace
Yes, roasting should also be done. ..but, uh, maybe not so much with plastics, eh. The acrylic would burn off quick enough (I imagine)."
Good to hear from you Topher.
Excellent point about the conformal coating process. But, from what I researched, it seems to be used more on completed PCBs and sub-assemblies. What I was referring to was working on de-populated, gold-plated CPU pins and other types of connector pins.
My hypothesis is that the de-populated items may be contaminated with organics from the recovery process. I am aware that most of those organics can be eventually dissolved in the AP recovery stage. But, it seems there are a lot of complaints about how long and slow that AP process is. This type of contamination could be part of the problem. Obviously, if this is occurring, part of the solution would be to be proactive and remove any organic contamination before the AP process is started. Removal could be done by aggressive solvents along with some type of mechanical scrubbing. Or, the use of some type of electronic parts cleaner:
Or, using a small butane torch (with an adjustable flame) to burn off the organics. Done right, it should burn off or cause the organics to be carbonized way before it vaporizes any thin Au plating. It should, also, be more economical than any other method.
Peace and health,
James
"Yes, conformal coating is done to get electronics IP rated (water/dust). . This can be as simple as acrylic (clear fingernail polish/clearcoat) or potting compounds. Circuits dont like water. It can bridge small gaps in pins and short out something rather quickly, or it can be slow and steady, essentially electrolysing the trace
Yes, roasting should also be done. ..but, uh, maybe not so much with plastics, eh. The acrylic would burn off quick enough (I imagine)."
Good to hear from you Topher.
Excellent point about the conformal coating process. But, from what I researched, it seems to be used more on completed PCBs and sub-assemblies. What I was referring to was working on de-populated, gold-plated CPU pins and other types of connector pins.
My hypothesis is that the de-populated items may be contaminated with organics from the recovery process. I am aware that most of those organics can be eventually dissolved in the AP recovery stage. But, it seems there are a lot of complaints about how long and slow that AP process is. This type of contamination could be part of the problem. Obviously, if this is occurring, part of the solution would be to be proactive and remove any organic contamination before the AP process is started. Removal could be done by aggressive solvents along with some type of mechanical scrubbing. Or, the use of some type of electronic parts cleaner:
Or, using a small butane torch (with an adjustable flame) to burn off the organics. Done right, it should burn off or cause the organics to be carbonized way before it vaporizes any thin Au plating. It should, also, be more economical than any other method.
Peace and health,
James
Martijn
Well-known member
I don't think organic pollution will slow AP down notably. The complaints about slow process are there because it's slow.
The organic pollution, if any, will be on top of the gold layer, where the AP works its way underneath the gold. Hence the foils.
Jewelry gets a long time exposure to skin fats and dirt, that could interfere with refining. I wouldn't worry too much about it with pins. Torch a small part of it and test if it makes a difference with a dirty batch of the same weight and type of pins. I dont expect much difference. I never have or needed to torch them.
About the parts cleaner, i don't know if introducing Tetrachloroethylene (MSDS: Avoid contact with strong
bases and strong oxidizers.) to AP will have unwanted side effects. You'll have to clean that again or make sure it's all evaporated and leaves no residue.
What did your pins look like after you've put them in AP? Was there a fine brown copper layer on them? And did the AP loose some green color? Then some copper could have cemented out on the tin or nickel layer, weakening the acid's copper reducing ability. Which slows things down even more. Adding HCL to dissolve the more reactive base metal layers will speed things up.
Bigger air bubbler! :lol:
Actually, more air means better conversion from CuCl1 to CuCl2, so yes. Watch out for fine mist and splatters. Don't overdo it. It still takes time.
The organic pollution, if any, will be on top of the gold layer, where the AP works its way underneath the gold. Hence the foils.
Jewelry gets a long time exposure to skin fats and dirt, that could interfere with refining. I wouldn't worry too much about it with pins. Torch a small part of it and test if it makes a difference with a dirty batch of the same weight and type of pins. I dont expect much difference. I never have or needed to torch them.
About the parts cleaner, i don't know if introducing Tetrachloroethylene (MSDS: Avoid contact with strong
bases and strong oxidizers.) to AP will have unwanted side effects. You'll have to clean that again or make sure it's all evaporated and leaves no residue.
What did your pins look like after you've put them in AP? Was there a fine brown copper layer on them? And did the AP loose some green color? Then some copper could have cemented out on the tin or nickel layer, weakening the acid's copper reducing ability. Which slows things down even more. Adding HCL to dissolve the more reactive base metal layers will speed things up.
Bigger air bubbler! :lol:
Actually, more air means better conversion from CuCl1 to CuCl2, so yes. Watch out for fine mist and splatters. Don't overdo it. It still takes time.
Martijn said:
Again, you have some very good points, Martijn.
I haven't done any pins or connectors (yet!). I never thought they were worth it and because I had no desire to build a sulfuric cell. The only AP process I have done is on gold foils from RAM sticks.
Now that I opened my big mouth, it looks like I'm going to need to test my hypothesis.
Sigh . . . !
James
So are you saying that I should torch these pins before I put them back in the AP?
Plated portion of pins, and associated receptacles, will have no additional coating of any kind. To do so would compromise the conductivity of the connection.
Unless the purpose of the equipment requires it, there is no need to add a coating on unplated portion of pins. If any such coating is present, but you can not see it, lightly scrape pin with edge of blade. Any coating present will be evident. Personally, I have never done so, but I did read something on one of the scrap metal forums several years ago.
Another item of importance that has been glossed over is the base material of pins. Differing alloys react differently. Some may take several days, or even weeks, for noticeable change to occur. Not all pins are created equal.
Thickness of underlying plating also has an effect. Gold on nickel on copper is relatively fast and easy. Pins are never pure copper and, in some applications, may have no copper at all. The less copper in the pin alloy, generally, the slower the etching occurs. In my experience, the process still works, if very slowly at times.
If time is of more importance than cost. That is if you value time over possible profit, go with whatever will dissolve the pins without dissolving gold. Much of the time that will nitric.
Have fun.
Time for more coffee.
Unless the purpose of the equipment requires it, there is no need to add a coating on unplated portion of pins. If any such coating is present, but you can not see it, lightly scrape pin with edge of blade. Any coating present will be evident. Personally, I have never done so, but I did read something on one of the scrap metal forums several years ago.
Another item of importance that has been glossed over is the base material of pins. Differing alloys react differently. Some may take several days, or even weeks, for noticeable change to occur. Not all pins are created equal.
Thickness of underlying plating also has an effect. Gold on nickel on copper is relatively fast and easy. Pins are never pure copper and, in some applications, may have no copper at all. The less copper in the pin alloy, generally, the slower the etching occurs. In my experience, the process still works, if very slowly at times.
If time is of more importance than cost. That is if you value time over possible profit, go with whatever will dissolve the pins without dissolving gold. Much of the time that will nitric.
Have fun.
Time for more coffee.
Rreyes097 said:
Why not? It can't hurt this batch (unless you get them too hot and vaporize your gold).
Everything that all the other responders to your original post have offered is all true. It sounds as if torching is the only thing you haven't tried. However, I assume that torching would provide more benefit with a new batch of pins/connectors.
All I'm saying is that try torching your new batches. Keep an eye out for smoke which would indicate some type of combustion happening due to contamination. It doesn't make any difference whether that contamination is from your handling or some other source.
Peace and health,
James
galenrog said:
Read that all again. There's a lot of wisdom in that post.
Dave
Martijn
Well-known member
I'm saying torching can't hurt with new pins. And that I'm not sure if it will do anything. That's for you to find out and decide. You are looking for a solution to a problem that is not causing the slow process imo.Rreyes097 said:
I would not pull pins from AP and torch them.
I think there are other, bigger factors that are delaying the digestion of base metals, as explained in this thread by me and others.
Displacement of copper is one, as I experienced once, leaving me with pale green solution in stead of deep green.
The composition of the base metal is another factor, as Galenrog explained. We speak of copper basemetal, but more often its brass, bronze, or some weird alloy with different layers of plating, all to make the item best suit it's purpose.
Ohiogoldfever
Well-known member
- Joined
- Nov 8, 2020
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I have some large pins that have been in AP for over a month and just started to alter the color of the solution. They are very thick coated high quality pins so I knew it would take a while.
Make sure whatever you are working with is clean of oils or grease. If they are clean when they go in then it’s just a matter of time. Stir them every now and again but fill your time with prepping more material.
Patience is a virtue my friend. I’ve not yet found anything pin related that won’t eventually dissolve in AP.
It’s cheap but slow. My life is much easier knowing I’m not in a rush to do things.
Best of luck.
Make sure whatever you are working with is clean of oils or grease. If they are clean when they go in then it’s just a matter of time. Stir them every now and again but fill your time with prepping more material.
Patience is a virtue my friend. I’ve not yet found anything pin related that won’t eventually dissolve in AP.
It’s cheap but slow. My life is much easier knowing I’m not in a rush to do things.
Best of luck.
