# Harvesting Fingers : Comments and Questions



## lazersteve (May 9, 2007)

Post your comments to the fingers tutorial here.


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## Noxx (May 10, 2007)

Interesting, Thanks.

But for me it's pins that are hard to take off. I don't have much tools in my garage.


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## lazersteve (May 10, 2007)

I'll make a video showing that process just for you Noxx. :wink:


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## Jackrabyt (May 10, 2007)

Don't worry Noxx, I have enough tools for 10 people around my place and it is still hard for me to get the pins. :lol: 

Nonetheless I would still love to see a video on pin removal by our local video deity (that would be you Steve  )


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## Noxx (May 10, 2007)

Well, this would be benefit for at least two person.


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## goldsilverpro (May 10, 2007)

When you talk of pins, what do you mean? Those 1000 or so wire wrap pins on a board or pins in connectors, etc.? Photos might help. A process for removing pins from plastics that was popular in the '70's was to freeze them in liquid nitrogen and then crush the plastic to powder. Couldn't the wire wrap pins be removed with a wide chisel?

Concerning the fingers, why is it so necessary to cut them off co neatly? I could understand this if you were selling them on eBay. If you're just refining them, what difference does it make? Of course, if you're keeping close records, cutting them close eliminates a variable. I'll probably keep to pliers or a vise. Actually, the fastest I've seen them removed was with power scissors.


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## Charlena (Jun 14, 2007)

all the different pin outs on a board and the best ways for each to get them off the best. I have just blistered my hands trying to get them off in their entirty and neatly. Im adding a photo of my de-populated boards...am I missing anything important by what you can tell from the photo..? any opinions welcomed!


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## lazersteve (Jun 14, 2007)

GSP said:


> Concerning the fingers, why is it so necessary to cut them off co neatly? I could understand this if you were selling them on eBay. If you're just refining them, what difference does it make? Of course, if you're keeping close records, cutting them close eliminates a variable. I'll probably keep to pliers or a vise. Actually, the fastest I've seen them removed was with power scissors.



Chris, 

The reason I urge members to cut the fingers as cleanly as possible is to cut down on the trash in the foils when stripped using AP, Dilute Nitirc, or HCl in the crockpot. The trash isn't a problem when the gold gets dissolved so I you do have good a point.

I suppose I'm just anal when it comes to each step of the process. In the beginning I never cared about the quality of cut fingers, but after processing a few batches I decided I didn't like all the board mask, SMD componnets, and plastic in my gold foils. One addiitonal plus to having a clean edge on the fingers when using the techniques that dissolve the base metals is that the foils don't get hung on the rough edges and grooves caused by the irregular edges. You've already mentioned the importance when you are trying to get good yield data.

Your mentioning of the power scissors is nothing short of amazing to me! Just last night my daughters boyfriend and I were cutting the fingers off of 50# of cards and he mentioned the same thing. You must be physic!!! :wink: Based upon yours and his suggestions I'll be buying a set for my air compressor rig tonight!

Thanks for the great input.

Steve


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## Charlena (Jun 14, 2007)

they work great and are quiet ---


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## Anonymous (Sep 27, 2007)

newbie here....This may be old news but a small tabletop shear will go thru PCB's like butter.....like you would find in a machine shop.

thanks to all the posters .....this is the most informative exchange as I have ever seen on a forum....all given freely......


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## Anonymous (May 4, 2008)

Hi, I'm new here. Are all "fingers" (no matter what they come off of) made with gold? If not, which one's aren't?


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## Rag and Bone (May 4, 2008)

If you look at the finger and it's gold, it's gold.


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## Anonymous (May 5, 2008)

Rag and Bone said:


> If you look at the finger and it's gold, it's gold.



So if it's gold-colored, it's gold & not copper or an alloy or something like that?

I have a CPU w/ gold plating that's a darker yellow than the fingers. I'm sure the CPU has gold on it, but I'm not sure about the fingers because of the difference.


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## Anonymous (May 5, 2008)

Another question... Instead of HCl + bleach, can I use H2SO4 + bleach?


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## goldmelts (Jul 4, 2008)

Hi, LaserSteve.

The below is regarding the videos of the AP refinement process. I have a few question that I hope you can answer.

HCL-peroxid
- would it be better to mix the HCL-peroxid first, then add to the fingers?
- When beginning the process you state that some of the gold is being dissolved. How can you limit this? how much of the gold actually get dissolved?
- you add ratio of 2:1 HCLeroxid. The during the video you add two more doses of peroxid, why? 
- if you don't add the additional two doses will the reaction still work?
- when straining the copper saturated solution you state that some of the gold has precipitated. who does this occur?
- when straining, you seem to disregard the precipitated gold. This is left in the filter. How can you make sure you don't loose this gold?
- how can you extract the gold that has gone into solution?


HCL-CL
-what is the concentration of the CL in the clorox?


Precipitation
- you used saturated smb solution - so you get this by adding SMB to water until no more SMB is absorbed by the water?
- Can you add to much SMB solution to the AUcl3?


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## lazersteve (Jul 4, 2008)

goldmelts said:


> Hi, LaserSteve.
> 
> The below is regarding the videos of the AP refinement process. I have a few question that I hope you can answer.
> 
> ...


The AP is most reactive when first mixed, the heat of the mix adds to the speed of this already slow reaction and is desireable in my opinion. It may actually work your way (most likely), but I've never tried it.


goldmelts said:


> - When beginning the process you state that some of the gold is being dissolved. How can you limit this? how much of the gold actually get dissolved?


Adding the Peroxide in smaller increments will lessen the attack on the gold. Since very little gold actually gets dissolved unless you use concentrated peroxide this is a minor point. Any dissolved gold will end up getting preciptated as the solution saturates.


goldmelts said:


> - you add ratio of 2:1 HCLeroxide. The during the video you add two more doses of peroxid, why?


To keep the reaction going. The peroxide converts the non-reactive CuCl formed into CuCl2, which does the actual etching of the copper substrate. You should read the Copper Chloride document on my website to understand the entire process involved.


goldmelts said:


> - if you don't add the additional two doses will the reaction still work?


Yes, but possibly slower. See my answer above.


goldmelts said:


> - when straining the copper saturated solution you state that some of the gold has precipitated. who does this occur?


The copper is saturating the AP mix which forces the gold out of solution. Copper is higher in the activity series than gold so it wins the battle of who will remain dissolved in the solution at higher concentrations. The activity series document is also found on my website.


goldmelts said:


> - when straining, you seem to disregard the precipitated gold. This is left in the filter. How can you make sure you don't loose this gold?


As stated in the video the dirty filter is aded to my filter box for later incineration and processing for the traces of gold in it. The gold is not lost, merely saved for a later day. You can waste a lot of time chasing traces of gold. Your time is better spent doing more productive processes. You can save up the traces to process in a meaningful way when they will warrant the effort of recovery involved.


goldmelts said:


> - how can you extract the gold that has gone into solution?


Reuse the solution until it is saturated with copper.



goldmelts said:


> HCL-CL
> -what is the concentration of the CL in the clorox?



The clorox is 5% sodium hypochlorite which is 

35.5 / 74.44 x 100% = 47.7% Cl by weight. 

So the answer is 5% of 47.7% x weight of household bleach used. 

The density of 5% household bleach is 1.09 g/mL.

So the weight of chlorine (Cl) in 1 mL of 5% household bleach is :

1.09 g/mL x 0.05 x 0.477 = *0.26 g per mL*



goldmelts said:


> Precipitation
> - you used saturated smb solution - so you get this by adding SMB to water until no more SMB is absorbed by the water?


Yes. You can also do the reaction with dry SMB if you desire. The extra water helps to cool the reaction when the gold solution is very concentrated. If you were to add too much the extra water also prevents the SMB from settling to the bottom as a solid with the gold.


goldmelts said:


> - Can you add to much SMB solution to the AUcl3?


See answer above. Additionally, Any copper II chloride present in the solution can be converted too insoluble copper I chloride by excess SMB. This can be removed by the proper washing techniques listed elsewhere on the forum.

I hope my answers help you understand the processes discussed.

Steve


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## goldmelts (Jul 4, 2008)

Thanks lazersteve  

Therefore, to drop out the gold in the AP solution, you simply saturate it with copper. This is done buy adding copper metal to the AP solution and let it be absorbed by the AP.

When doing this, can you add too much copper? That is, when trying to precipitate the gold if you leave the solid copper in the AP solution too long, will the copper precipitate out of solution and contaminate the already precipitated gold?

I'm assuming that after you have saturated the AP solution with copper, you drop the copper with steal, then you can reused the AP solution? How does rejuvenating the AP solution work?


Goldmelts


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## lazersteve (Jul 4, 2008)

Don't add any pure copper metal. Just reuse the AP directly on more gold bearing scrap to get the copper levels high enough to precipitate the gold out. 

Once you cement out the copper with iron the solution is no longer useful. If you are going to reuse it you must bubble air through it or add more peroxide as needed. The copper must be in tact for this to work You really should study the copper chloride document on my website to understand all that I'm saying. Once you've read it you should be up to speed.

If the solution becomes overly saturated with copper then copper I chloride will precipitate out as an off-white to gray/green sludge. It's easily removed from the foils and powdered gold with HCl washes as shown in the AP video.

Steve


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## goldmelts (Jul 4, 2008)

cool, I'll give your document a read.


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## maltfoudy (Jul 20, 2008)

i use a vice and a sheet metal vice grip with 6 inch wide jaw and just snap the edges off,takes seconds and no expensive power tools needed


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## goldup (Sep 2, 2008)

Hello everyone.

I have gold foils in a filter. I need to get them into a plastic container to do the acid/clorox treatment. Is it ok to rinse the filter with water to get what is stuck to the filter out and into the container? Will the water need to be gotten out?

The fingers video leaves us with the foild in the filter. That is where I am. The next video shows the foils in a plastic container. I need to know how to get them there.

Thanks,
Kbow


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## lazersteve (Sep 2, 2008)

Kbow,

Wash the foils in with the spray bottle.

Pour off the excess water and proceed to the HCl-Cl dissolving.

Steve


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## goldup (Sep 2, 2008)

Thanks Steve!!!!

I feel like a kid at Christmas.


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## flankdrive04 (Feb 3, 2010)

Hi Steve, haven't been on for a while but I have a question.

once you have a container full of finger foils, what would you end up with (gold content or carrat wise) just by melting down the finger foils themselves?

Regards.


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## patnor1011 (Feb 3, 2010)

your foils can still be contaminated by copper so hcl/cl step will help to better quality of your gold


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## jimdoc (Feb 3, 2010)

It's so easy to finish it up from where you are now, I think it would be a mistake to melt it as is. Either do the final step, or keep it as is.
Jim


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## flankdrive04 (Feb 3, 2010)

thank you both for your feedback.

I guess I'll go the extra step!


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## samuel-a (Feb 4, 2010)

about pins ...

a simple locking pliers are the best thing i found for plunking almost all types of pins 

http://en.wikipedia.org/wiki/File:Locking_pliers.jpg


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