# Partially plated pins won't disolve



## Rreyes097 (Sep 5, 2021)

So I have these partially plated pins that I got awhile back. They may be only partially covered in Gold but the part that is covered in gold looks pretty good. So I determined that they were non-magnetic and I thought maybe a slow AP process would be helpful since I was low on nitric and my sulfuric cell is no longer operational since I had to give back the power source. I borrowed it. Below is the picture of a few, and how they look right now. Well I put them in AP a few days ago with a bubbler and they ran for a day or two and nothing happened no color change in the acid. No dissolving a base metals. So I took that HCL out or I mean AP. And put some new AP in there maybe a 5:1 ratio. Put it on heat still nothing happens. I asked a fellow refiner and he suggested perhaps putting it in a little bit of sulfuric acid a test run of about 10 pins. And then a few drops of nitric acid to see if the base metals would dissolve. Well here's another picture, a picture of a pin after doing said test. As well as what the liquid looks like now. It's white and milky with a bluish tint and most of the pins still have most of the base metals on it. Could you tell me what this white milky substance is? is it silver chloride? Also there is a screenshot of what the pins came from. It's just a screenshot of some pins that someone is selling on ebay. But they look just like the pens I have but still in the plastic. And their plastic is clear whereas mine was white. Any helpful advice would be appreciated I only did those 10 pins as a test run and it doesn't look like sulfuric acid and nitric acid it's going to be the answer.


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## butcher (Sep 5, 2021)

Cupric chloride will not attack gold ( unless a strong oxidizer is added), if the gold plating is thick the solution may not be able to contact the copper or base metals under the gold.

you can try cutting the pins into small pieces, or use oxidizer to attack the gold.


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## Rreyes097 (Sep 5, 2021)

What kind of oxidizer? What's a good one? Because hydrogen peroxide want strong enough. Also it is only half plated with gold. Shouldn't the acids be able to get to base metals via the unplated portion?


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## butcher (Sep 5, 2021)

If those are wire wrap pins you should be able to attack base metal without using a strong oxidizer, if you have free HCl in a concentrated enough solution with air bubbled into solution forming cupric chloride CuCl2 to attack the copper and other base metals, if too dilute and not acidic enough the green solution would look blue with white salts of cuprous chloride CuCl...

Copper will not dissolve in HCl unless an oxidizer is involved.
Gold will not dissolve in HCl unless an oxidizer is involved.
Air is a strong enough oxidizer (bubbled into the acidic solution) will dissolve copper, but is not a strong enough oxidizer to effectively attack gold, 3% hydrogen peroxide is slightly stronger oxidizer than bubbling in air, and can be used to attack copper with limited attack to gold.

If you cannot dissolve copper in your acid you may not have enough dissolve oxygen in solution, or the acid is used up making salts, cold temperatures will hold more gases such as oxygen, but cold acids may not attack metal as fast as a warmer acid (two side of the same sword).

My eyesight is failing those look like wire wrap pins, if you included wire you may possibly have tin, lead or other metals involved thus the white salts.

if very dilute maybe you converted your cupric chloride CuCl2 into cuprous chloride CuCl which would not attack copper (also a white powder or salt of copper).




To dissolve gold we need a stronger oxidizer.
30% H2O2 and HCl acid will attack gold.
Nitric acid and HCl acid will attack gold.
Chlorine gas and HCl acid will attack gold,
sodium hypochlorite (bleach) and HCl acid will attack gold
Most any chemical that converts HCl acid or forms chlorine gas in solution will also attack gold. 
Other strong oxidizers like perchlorate or MnO2...


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## Rreyes097 (Sep 5, 2021)

I have tried HCl and peroxide and air twice with fresh solutions. I was thinking nitric and distilled water. The pins are clean no wire and no solder or tin visible. So I don't know what to do.


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## Ohiogoldfever (Sep 5, 2021)

I use AP on a regular basis. By my estimation you’re just in to big a hurry. Cut a few pins to open up to the copper, or even add in a little Old AP if you have any. Toss em in there and stir them ever few days. 

I find with AP being in any hurry works against you.


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## Martijn (Sep 6, 2021)

I have done those 19" rack ESD controller pins in AP. You can pop them open with some prying, leaving the internal plated parts to be shaken out. The way you have cut them from the socket, you should have enough copper exposed for AP. Even without cutting them I dissolved fully plated pins in AP, just need some patience. Mine took 2 months last time. 
With this type you will have to get the plastic part open to get the pins out, AP will eat away base metals leaving gold foils inside the sockets. A pain to get them out. 

And may I advise wearing gloves when holding beakers with toxic chemicals in it, especially when posting pictures (on this site) ? 
We prefer pictures of good practice. It's not lemonade and cookies we're working with here. You can take one off to operate the camera. Many people can see your post, and do not realize the risks, like most You-Tube video's. Monkey see, monkey do, monkey gets some health issues.


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## kurtak (Sep 6, 2021)

Ohiogoldfever said:


> By my estimation you’re just in to big a hurry.



What Ohiogoldfever said --- You are just in a big hurry

The AP process is a VERY SLOW process & as I understand it can take weeks (like a month or more) to dissolve something like copper/brass pins

I have never used the AP process for that very reason --- I always used nitric - done in a day --- but then I got my nitric VERY CHEAP

Kurt


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## kurtak (Sep 6, 2021)

Martijn said:


> Mine took 2 months last time.



What Martijn said



> I was thinking nitric and distilled water.



That will get the job done in a day --- but if you are paying more the $7 per gallon for the nitric it will likely cost more then the gold is worth --- which is why most members use the VERY SLOW AP process 

Kurt


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## Rreyes097 (Sep 6, 2021)

I had them in AP for at least 3 days with no reaction whatsoever. But I guess I'll try it again or nitric and water I don't know Also I apologize for the lack of gloves in the picture I swear I usually wear gloves it was just a spur of the moment shot I wanted to try to get a picture of the bottom of the beaker. So I guess I can wait and put them in AP longer than the three days I tried already.


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## galenrog (Sep 6, 2021)

Three days May not be long enough. I have had batches of pins in AP for several weeks, with bubbler, before any noticeable reaction. Some material takes a lot of time. 

Just an observation, but you seem to be in a hurry at times. Patience is truly a virtue in this business. No everything can be done in a day, a week, or even a month. Slow down. Take notes. Learn from others. 

Time for more coffee.


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## Martijn (Sep 6, 2021)

When did your solution start to show white residue? After the nitric addittion? 
Then it will likely be tin paste from the bronze base metal (copper + tin) therefore nitric not will give the desired result with bronze pins imo. You'll have foils in tin paste to process. Incineration and HCL leach to get that tin out. 

I did not find any silver in this type of pins. It's gold on nickel on a spingy type of bronze core.

If the white stuff dissolves in HCL and turns green, then it most likely is copper 1 chloride. The formation of that indicates a weak AP and HCL addittions are needed. You will have to add HCL several times to completely dissolve all base metals. So keep some room in the bucket. And suspend the pins from the bottom by hanging them in a perforated bucket. And you can shake and rinse a bit that way. Air bubbler underneath. 
I made my perforated basket from a big plastic jar with a hot needle on a piece of wood to poke the holes. Just big enough to flush foils through. 

No need to replace AP. It's the copper 2 chloride that does the job, not the HCL. As long as there is some free HCL to turn it back into copper 2 chloride. The formation of the insoluble white stuff is a sign that more copper is going into solution than the air and HCL can convert, if the pins get covered by it, the acid can no longer reach the pins and reaction stops until all CuCl1is dissolved again. 

Martijn.

Edited to change brass into bronze.


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## FrugalRefiner (Sep 6, 2021)

Brass is an alloy of copper and zinc. Bronze is an alloy of copper, tin, and sometimes other elements.

Dave


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## cosmetal (Sep 6, 2021)

A question for those who have knowledge of electronic component manufacturing processes:

Do the makers of these thinly plated pins/components ever top-coat the exposed parts with any type of clear-coat to aid against wear and tear abrasion? Or would that have too much of an effect on electrical function?

It is also possible that oils from your fingers are transmitting to the pins during dissembling. Why not use a handheld butane mini-torch that jewelers use and fan a bushy flame over the pins before refining and burn off any contamination before the AP process?






An example - many more can be found on Amazon.

Peace and health,
James


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## Martijn (Sep 6, 2021)

I realized it just after i wrote it and edited. :lol: 
But yes, i encountered a lot of tin paste back when i made my first attempt and mistakes when starting this journey. Pins in nitric. So i assumed its bonze. Or a tin plating layer. 
Thinking back, there may have been some solder in the mix, so there goes the assumption it's bonze. :?: 
I think i read it somewhere too.


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## Martijn (Sep 6, 2021)

cosmetal said:


> A question for those who have knowledge of electronic component manufacturing processes:
> 
> Do the makers of these thinly plated pins/components ever top-coat the exposed parts with any type of clear-coat to aid against wear and tear abrasion? Or would that have too much of an effect on electrical function?
> 
> ...



I dont think so. If there was a conductive wear resistant coating out there, why bother plating with gold?
Heavy duty parts get thicker plating.


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## cosmetal (Sep 6, 2021)

Good point - but what about potential contamination by body oils?

James


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## Martijn (Sep 6, 2021)

Burn them off! 
I see sreetips do it to all his jewelry and clean scrap every time. So yes. Good idea.


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## Rreyes097 (Sep 6, 2021)

I thought I just posted reply is it not there?


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## Martijn (Sep 6, 2021)

No.


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## Rreyes097 (Sep 6, 2021)

Dang it was a long post. Not looking forward to re doing that.


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## Rreyes097 (Sep 6, 2021)

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?


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## jimdoc (Sep 6, 2021)

Did you stir it once in a while? Or use an air bubbler?


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## Gold (Sep 6, 2021)

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!


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## Martijn (Sep 7, 2021)

Rreyes097 said:


> 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?



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.


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## kurtak (Sep 7, 2021)

Rreyes097 said:


> What did I do or say to indicate that I'm in a hurry to everybody?



The following quotes from your different post's are what indicate that you are in a hurry

From your "first post" 



> Well I put them in AP a few days ago with a bubbler and they ran for a day or two and nothing happened no color change in the acid



from a couple other posts



> I had them in AP for at least 3 days with no reaction whatsoever.





> 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



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


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## kurtak (Sep 7, 2021)

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


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## Rreyes097 (Sep 7, 2021)

I clearly understand and hear you all. I just have never had this happen.


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## Topher_osAUrus (Sep 8, 2021)

cosmetal said:


> A question for those who have knowledge of electronic component manufacturing processes:
> 
> Do the makers of these thinly plated pins/components ever top-coat the exposed parts with any type of clear-coat to aid against wear and tear abrasion? Or would that have too much of an effect on electrical function?
> 
> ...



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:


> 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
> 
> ...



....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!)


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## Rreyes097 (Sep 8, 2021)

They aren't in any plastic anymore.


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## Martijn (Sep 8, 2021)

Topher_osAUrus 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).
> 
> ...



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:


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## cosmetal (Sep 8, 2021)

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


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## Martijn (Sep 8, 2021)

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.


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## cosmetal (Sep 8, 2021)

Martijn said:


> 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.
> ...



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


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## Rreyes097 (Sep 8, 2021)

So are you saying that I should torch these pins before I put them back in the AP?


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## galenrog (Sep 8, 2021)

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.


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## cosmetal (Sep 8, 2021)

Rreyes097 said:


> So are you saying that I should torch these pins before I put them back in the AP?



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


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## FrugalRefiner (Sep 8, 2021)

galenrog said:


> 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.
> 
> ...



Read that all again. There's a lot of wisdom in that post.

Dave


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## Martijn (Sep 9, 2021)

Rreyes097 said:


> So are you saying that I should torch these pins before I put them back in the AP?


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. 
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.


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## Ohiogoldfever (Sep 9, 2021)

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.


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## Rreyes097 (Sep 9, 2021)

No rush my friend. They are actually still sitting there. Been finally processing my 6.16lbs. of fingers and other bits like sim cards and such. Looks like a good return. Still cleaning the gold and haven't been able to weigh it yet. I'm excited to weigh it!


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## Ohiogoldfever (Sep 11, 2021)

6.5 lbs of fingers should be an interesting yield.


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## zumka (Nov 10, 2021)

Hello, everyone.

Just wondering if hdd pins have any obvious difference than others. (like other than cpu pins, cd/dvd rom pins ect?). I mean the base metal under and yield difference. 

I depopulated 350 hard drive PCBs, removed the chips and wanna know which process i should follow for the pins. Or is it worth the trouble? (i mean hobby-wise. even a single gram of yield would make me happy. cost of procedure doesn't matter.)

Roughly half of them SATA, half of them IDE. (Hard disks from between 2000-2015. Mostly samsung, seagate, western digital and maxtor)

Thanks in advance for any kind of response,

Zuma.


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## cosmetal (Nov 10, 2021)

zumka said:


> Hello, everyone.
> 
> Just wondering if hdd pins have any obvious difference than others. (like other than cpu pins, cd/dvd rom pins ect?). I mean the base metal under and yield difference.
> 
> ...


*I depopulated 350 hard drive PCBs, removed the chips and wanna know which process i should follow for the pins. *You have my sympathy - I just finished <100 of them.

If you plan on continuing to work on partially plated pins and are experienced enough to work with sulphuric acid, building a sulphuric cell would be the way to go.

As far as any difference between the pins from other sources - everything will vary from device-to-device and manufacturer-to-manufacturer.

The hard science we deal with is at the chemistry level. Trying to guess what a manufacturer has done with their product to stay competitive isn't a hard science with predictable outcomes and would drive me crazier than I already am.

Wait! Maybe a test tube refine and comparison would be interesting. See what I mean when I say crazy.

Peace and health,
James


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## zumka (Nov 11, 2021)

Thank you for your answer, James. I'm experienced enough to deal with sulphuric, but not eager enough to supply the instruments of sulphuric cell just for this batch.

And yeah, i think if we'd know the EXACT yield from the beginning, wouldn't be so interesting, no? So, i changed my mind, don't wanna know how much the yield gonna be. Just wanna find the best way to get the max amount of it except with sulphuric cell.

Cheers,
Zuma


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