# Rock tumblers



## Woodworker1997 (Aug 15, 2012)

Has anyone ever tried using a rock tumbler loaded with ceramic pellets to remove gold plating from pins or other plated objects?

Please be nice I am extremely new to this. The chemical processes described in this forum honestly are a little intimidating. The only chemistry i know is Dihydrogen monoxide kills thousands of people a year. :lol:


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## Oz (Aug 15, 2012)

Woodworker1997 said:


> The chemical processes described in this forum honestly are a little intimidating. The only chemistry i know is Dihydrogen monoxide kills thousands of people a year. :lol:


Well chemical refining may not be for you then. We use a good deal of that hazardous stuff in our chemical reactions.


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## element47.5 (Aug 15, 2012)

I don't think that would be a beneficial means of attacking the problem. I just can't imagine that working very well. If you loaded up a tumbler with pins, most of them would be very lightweight and in numbers, they would just knit themselves into a mass that would sort of protect the individual pins from being struck by the (in this case) ceramic balls. And the balls would have to be of small, tiny diameter, thus they wouldn't hit with much force. I don't think you could even count on the gold plating being "knocked off". 

No, you need the 100% contact of the pins being immersed in a liquid. 

You are absolutely right to respect the hazards of some of the chemicals and some of the chemical reactions. No two ways about it. For me, myself, I have come to the conclusion that, particularly in light of the amount of materials I can reasonably expect to gather, I cannot set up an acceptable lab that I can leave undisturbed, with a means of evacuating vapors and providing a place to melt materials and otherwise providing for safety and storage of hazardous containers of wastes. I have thought long and hard about it and that's just the conclusion I've come to, speaking for myself only. You know, the flipside of that conclusion is, if there was an functional way to gather, process, recover and refine the metals that DIDN'T use hazardous and expensive acids, arcane glassware, and all manner of safety gear, you gotta know that the experienced members here would eagerly try them and use them. This ain't the "Fun with Nitric Acid" forum, LOL. 

That absolutely does not mean you cannot learn about the techniques and perhaps more importantly, gather the raw materials from which posters seek to recover and refine PMs and profit therefrom. I'd be very comfortable saying that among the posters on this forum, as a group, the ones who simply gather materials and ship off to someone else to refine make as much money as the ones who actually refine and melt. And if you took out Lou, 4metals, and a small handful of other professionals whom we are very lucky to have in terms of their experience and insights, the sender-offers would make more.


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## goldsilverpro (Aug 15, 2012)

Woodworker1997 said:


> Has anyone ever tried using a rock tumbler loaded with ceramic pellets to remove gold plating from pins or other plated objects?


I have. I once tried every type of abrasive I could think of, wet or dry, in a rock tumbler, to remove gold plating by abrasion. Never had 100% success. Even if I had been successful, I would have had to use some chemicals at the end. You just can't escape the use of the chemicals.


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## Woodworker1997 (Aug 16, 2012)

element47.5 said:


> I don't think that would be a beneficial means of attacking the problem. I just can't imagine that working very well. If you loaded up a tumbler with pins, most of them would be very lightweight and in numbers, they would just knit themselves into a mass that would sort of protect the individual pins from being struck by the (in this case) ceramic balls. And the balls would have to be of small, tiny diameter, thus they wouldn't hit with much force. I don't think you could even count on the gold plating being "knocked off".
> 
> No, you need the 100% contact of the pins being immersed in a liquid.
> 
> ...





Thank you for the great advice. Your comments have pushed me into the direction that I have been contemplating for awhile.I have been collecting and stripping PM components for about 8 months now. Selling what i collect sound like my best option. 

I have been manually removing and separating components from lots of different sources. I dont have a problem doing this by hand (keeps me busy and kind of relaxing). What i do find difficult is lifting gold plated copper traces from circuit boards. Mil spec boards are not too much trouble but, newer cell phone boards with thinner plating are troublesome. Any advice?

PS. Thanks to everyone on the forum. This pool of knowledge has been very enlightening!


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## RESET (Aug 16, 2012)

Woodworker1997 said:


> The only chemistry i know is Dihydrogen monoxide kills thousands of people a year. :lol:



Yup, breath in a little bit of that stuff and you are a gonner.


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## joem (Aug 16, 2012)

Question: What is harder, the plating on fingers and pins or ceramic cpu? If ceramic is harder can you use crushed ceramic in a tumbler with pins?
sjchjjldhgfkjll
he he my snake wrote that last part


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## butcher (Aug 16, 2012)

That is a pretty snake but you need to teach him to use spellcheck.


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## NoIdea (Aug 17, 2012)

goldsilverpro said:


> I have. I once tried every type of abrasive I could think of, wet or dry, in a rock tumbler, to remove gold plating by abrasion. Never had 100% success. Even if I had been successful, I would have had to use some chemicals at the end. You just can't escape the use of the chemicals.



I find that once you have subjected the gold plated item's to some sort of abrastion, a tumbler, then heat them up to at least 550deg C, then place them in a flat low sided tray, dampen them with your favourate electrolyte, what ever waste digestion acid (AP, HCl/Cl, etc) you have on hand, then let it sit for a few days, just keeping it damp, half covered, then after, wash all the mud into a keeping container, tumble pins and rewash then repeat the process. Heat, tumble, oxidize, wash. 

Eventually all the values will just wash away with the mud, treat mud as you would when following any of the well know practaces found on this forum. 

Gives you brass/copper pins for sale.

Currently processing around 8kg of mixed grade pins.

Joe - yup, i use exactly that, old crushed up ceramic CPU's for my tumbler, works great.

Deano


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## NobleMetalWorks (Aug 17, 2012)

I have thought several times, that glass or sand blasting might readily remove the gold from boards, but I'm not sure if you could retain all the values. I think it would have to be done in a glove box. I'm also not sure about any other materials that might be knocked off, PCBs, etc. 

If the material you used to sand blast with dissolved with acids, like borax can in hydrochloric acid for example, you could easily remove the glass from the solution at the same time you removed base metals. You could precipitate the glass to be used again later. Anyone try this and have any positive experience with processing boards this way?

Scott


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## joem (Aug 17, 2012)

butcher said:


> That is a pretty snake but you need to teach him to use spellcheck.



Yeah he has been on the forum before and I warned him if he keeps using text lingo he will be banned.


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