# Strip gold plate off of elements?



## driver8 (Jun 15, 2017)

Hi all, 
brand new to this so still in learning stages.
I have been researching gold recovery of computer parts, but I have a different application and have not found any forums regarding gold plate applied directly to nickel.
I have a lot of gold plated elements that are at my disposal. I accessed what I suspect is the patent, and from what I can gather the plating is specified to be 24k gold plate, no less than 10 microinches with an RA of 15 microinches or less. The plating is the finished layer, and is applied to a sub layer of bright nickel which is around 200 microinches, then a base layer of strike nickel.
While I realize the plating is not a thick plate, the diameter of the finished rod is around the diameter of a #2 pencil, and if unlooped would total around 40 inches in length per each unit.
It is for all intents and purposes a heating element, so has electrical current carrying capabilities.
My question is, since it is only plating removal of something that is set up for conducting electricity already, would there be a way remove the plating without having to dissolve all of the nickel in the process?
I am not a chemist by any stretch, and am nervous about chemicals, so the less caustic solution I can find the better, although I realize it's hard to make an olmlette without breaking a few eggs along the way.. AR technique puts a whole lotta fear into me.

Add to that, the overall length of the material is much different than fingers and pins and pcb's , and I am only dealing with a plated surface only to remove from a nickel underlay instead of dissolving computer parts to get to the gold plate?

I read a lot about reverse electroplating, would that be the best path? Considering I have a way to conduct current/heat; if so, is there a way to do it en mass in a container larger than a beaker that would fit a third of the length of what I am dealing with? Or should I just chop it up?

Any other suggestions on methods or similar applicational experience??
Pic attached. 
Thanks for any advice..
Driver 8


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## goldsilverpro (Jun 15, 2017)

What's the base metal?

I would probably use cyanide if it were mine. It's by far the simplest. However, in your case, the so-called reverse plating in nearly concentrated sulfuric acid would be your best bet. However, it's a nasty acid if it gets on you skin or clothing. In both off these types of strippers., the gold is removed (stripped) without attacking anything else. 

In the last few years there have been a rash of pre-formulated strippers available for sale and several have been experimented with on this forum. I haven't kept up with these, but I know that some contain cyanide. Maybe some of the members with experience in these can chime in.


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## driver8 (Jun 15, 2017)

Thanks for the input goldsilverpro. 
This is the word for word off what patent I think is related to the composition of the layers:

A 0.375 inch diameter tubular element made of incoloy is coated with an adhesion layer of nickel chloride using a Woods nickel electroplating bath. A bright nickel layer having a thickness of 0.0002 to 0.0004 inches is electroplated on the nickel chloride layer using a bright Watts nickel electroplating bath. Finally, a layer of hard 24 karat gold having a minimum thickness of 0.00001 inches is electroplated onto the bright nickel layer.


The dilemma I am having is that I don't just have 1 of these, I am currently in possession of over 30 of what is pictured, and I I refer to the overall length of each unit, which is between 9 to 15 inches and 1"X1" " square footprint" of the 4 tubes that comprise one unit, which means I would need a large container both in height and in girth to be able to completely submerge 1 unit consisting of 4 rods let alone multiple units.

I could have access to a drain cleaner that says it is 93% "buffered" sulfuric acid, msds states that it is comprised of sulfuric acid and oil of vitriol? at <50% by weight? Would that be sufficient to strip the gold on its own without any other additions?

Drain cleaner:
http://www.floweasy.com


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## kurtak (Jun 16, 2017)

My first option would be as GSP suggested - cyanide - but that is likely out of your ball park 



driver8 said:



> A 0.375 inch diameter tubular element made of incoloy



Per the underlined - incoloy is basically made up of the same elements (metals) as stainless steel just that it is lower in iron & higher in chromium & nickel (so its actually in the SS family) the reason it is higher in Cr & Ni then common SS is it is used in "high" temp &/or chemical resistant applications where ordinary SS just isn't good enough 

Trying to dissolve the base metal away is not going to happen (at least not in any effective/efficient manner) 

So - my next option would be to test a piece & see if reverse AR would work --- the problem with reverse AR is the larger amount of nitric you need compared to normal AR - & nitric is usually hard &/or expensive for most new members just getting started at gold recovery/refining

My last option would be the sulfuric stripping cell simply because I prefer not to work with sulfuric acid unless I absolutely must



> I am not a chemist by any stretch, and am nervous about chemicals, so the less caustic solution I can find the better, although I realize it's hard to make an olmlette without breaking a few eggs along the way.. AR technique puts a whole lotta fear into me.



If you are afraid of working with AR (or other acids) you should be even more afraid of working with sulfuric acid --- sulfuric acid is a MUCH more dangerous acid to work with the nitric, HCl (muriatic acid/hydrochloric acid) or AR

Kurt


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## goldsilverpro (Jun 16, 2017)

driver8 said:


> Thanks for the input goldsilverpro.
> This is the word for word off what patent I think is related to the composition of the layers:
> 
> A 0.375 inch diameter tubular element made of incoloy is coated with an adhesion layer of nickel chloride using a Woods nickel electroplating bath. A bright nickel layer having a thickness of 0.0002 to 0.0004 inches is electroplated on the nickel chloride layer using a bright Watts nickel electroplating bath. Finally, a layer of hard 24 karat gold having a minimum thickness of 0.00001 inches is electroplated onto the bright nickel layer.
> ...



Just for your information, there is no such thing as "hard" 24K gold. Hard gold is hard because either cobalt or nickel has been alloyed with it. Not much, though - 1% at the most. Oil of vitriol is sulfuric acid. I don't understand the <50% by weight part. If the sulfuric acid is truly less than 50% by weight, that will NOT be satisfactory. The sulfuric should be at least 85% by weight. The buffer might cause problems but maybe not. Concentrated sulfuric drain cleaner without buffers or inhibitors is available. The members can probably suggest a brand.

There are many incoloy alloys but they all are primarily made up of Fe/Ni/Cr. I still think your best bet is the reverse plating concentrated sulfuric acid. It should strip in a minute or so. I would run them one at a time since you only have 30 of them. Assuming an average length of 12" and a thickness of 10 microinches (.000010"), the total gold value on 30 pieces would be about $54 or 1.33 grams.


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## Topher_osAUrus (Jun 16, 2017)

goldsilverpro said:


> The members can probably suggest a brand.
> .



Rooto
Liquid fire

There are a couple brands that have the inhibitors, what they are, no clue. One of those with inhibitors is also a pink color.

I havent had issues with it when using it in my AR, or making copperas, but when I used it in my sulfuric cell, it seemed to take forever and a day to settle the gold out completely. I ended up filtering it through a fiberglass charmin plug because there was some that didn't even sink to the bottom after a month of sitting there.


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## driver8 (Jun 20, 2017)

Thanks for all the input all.

My math is not up to par either (I was the A+ Spanish student), but using the string around the rod for circumference technique I get a circumference of 1 inch per rod.

If each rod is 12" long and 1" in circumference then one rod comes up to 12 sq inches surface area???, and using gold plating surface area calculator on goldnscrap.com I come up with $1.51 per rod..

Each element has 4 cylinders (or rods), and I have 30 or more elements. Picture was of one element, with 4 rods..

Based off of $1.51 per rod, and 120 rods, aka 30 elements (@4 rods per element) I get a completely different potential yield amount of $180ish for 30 elements AKA 120 rods.

Am I way off on my calculations here??? It would not be the first time... had to take my shoes off to get this far..

If I am completely wrong, where did I go wrong? 

Thanks for your insight!!!


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## Lino1406 (Jun 20, 2017)

For information: Oil of vitriol - old name for sulfuric acid


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## Martijn (Sep 17, 2019)

Kurtak, you said: "If you are afraid of working with AR (or other acids) you should be even more afraid of working with sulfuric acid --- sulfuric acid is a MUCH more dangerous acid to work with the nitric, HCl (muriatic acid/hydrochloric acid) or AR"

Can you explain why sulpuric is more dangerous? I think the NO2 is pretty dangerous. I stripped 5 kilo of plated pins and got13.6 gram gold from it. Had no problems. Worked with 96%.


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## nickvc (Sep 18, 2019)

In case Kurt misses your question let me answer for you, the real problem with working especially with concentrated sulphuric is that it is hydroscopic, ie if left open to the air it will draw water from the air which is why it’s advised to cover your cell, now if it can do that to air consider what it can do to the human body which is nearly all water, if the sulphuric is warm or even worse hot it reacts even faster and any fumes which you may inhale will wreck your lungs.


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## butcher (Sep 18, 2019)

H2SO4 will burn sugar to carbon, a raw chicken drumstick turns to a gelly looking glue (bone and all the flesh)...

NaOH will dissolve a human body making soap.


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## Shark (Sep 18, 2019)

If you have already got the sulfuric acid try this.. Take one drop of it full strength and place it on a dry piece of wood, such as building lumber. What will happen, if it is 93% or stronger, is where the acid touches the wood will almost instantly turn black. When it dries it will be black coals (like charcoal) as if you burnt it with a torch. It burns skin faster than it does wood because of the moisture in the skin. While I have and will use a sulfuric cell again I always use extreme caution. Sulfuric acid is some really nasty stuff if used recklessly. Learn as much as possible before attempting to use these cells.


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## Martijn (Sep 18, 2019)

Ok. Thanks for the advise. I'm always very carefull with any acid. I know about the reaction on organic things. Pretty nasty. I've been studying gold refining since 2014 reading the forum and hoke and much more before attempting anything about 3 years ago. Built a fumehood and scrubber for NOX and other nasty fumes. I work with a 200ml glass for the cell and close it after stripping. Siphon it off after settling and reuse the most. Doesn't seem to absorb much water. Very carefull with the acid using PPE and neutralising water nearby. But never had any fumes coming of the sulfuric. That NOX and chlorine gas is something to handle with care. Also cant blow it out without scrubbing. Have to think about the neighbours.Great hobby though.


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## Shark (Sep 18, 2019)

Sounds like your well on the way. I have seen fumes from heating sulfuric, the best advice I give on that is you don't want to see it and to avoid that situation. It is a good idea to use a remote cutoff in case of accidents that way you don't have to approach the stuff to turn your cell off if it does get hot. 

I have about 20 pounds of gold plated stuff I need to run, I just haven't had the time lately.


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## Martijn (Sep 18, 2019)

I use a laser temperature meter to monitor it and i can turn it off outside the fumehood when it gets to hot. It never goes over 35Celsius. And with my PS I can limit the amps. I never go over 2A and 9 V.


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## nickvc (Sep 19, 2019)

Sounds like you know what you are doing so you do not have to worry too much but you asked why sulphuric was considered more dangerous than nitric or Hcl so we pointed out it’s dangers so that not only you but others may understand if they read this at a later date with little to no knowledge of chemicals.


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