fingers and other plated boards

Hi;
I was wanting to know just how much non gold/copper can be put in with fingers without causing problems to the process. I have boards that are plated both sides. Some parts I can simply break off and will be clean of solder but some parts will have just a bit of solder on one side. Can I still put this in with the fingers ?
Also if I have small components that are gold and whatever type metal , can i put them in with fingers ? Just a few small parts.

In the pics the small squares are only about 1/4 inch . that is front and back of the square. Just an example of what I am speaking of when I say a bit of solder on one side.

The large boards are lnb . the dark colored one is all gold it just looks like copper in pic and I scraped all parts off with blade. My question on these is how best to proceed. Can I put in HCl and eat away the solder and then AP / HClCl like fingers ? I thought I would not want to just toss in AP because all that solder would contaminate useful AP so perhaps just HCl first as I can save HCL for only this type process.

I am interested in this, as I have a similar question.

The best solution I have heard so far is to depopulate the boards with nice cheap NaOH sodium hydroxide. I know many on the board pretreat/depopulate with hcl before Hcl/peroxide, but the waste is toxic and needs disposing of separately/safely and for a tightwad like me its ten times the cost.. the sodium hydroxide with tin hydroxide I believe is safe enough to be diluted and disposed down sewerage.

Is there anyone who can disabuse me of this idea? I plan to start depopuating prior to ap shortly.

lead is very toxic. treat waste properly, do not dispose of any of this into the sewage. People down river drink what people upriver flushed.

lead free boards and solder have been required since 2006 and all of the boards that I work with are Pb free, and seem to be marked as such going back to 2000. The SAC solder used is silver/tin /copper, so I think I should be safe. Tin will be dissolved and silver, copper precipitated, Tin hydroxide is apparently safe to enter our waste water system, as is unused Na0H. Waste water in the uk must go through processing and testing before it is allowed back into the fresh water system be it rivers , seas or pipework

I will be observant to ensure that any wastes with lead in are disposed of properly

clearstream, how do you dissolve solder with lye ? All I have used it for is to remove solder mask , which I have always referred to as " green paint" and never read about anyone using it for solder or parts.
My main objective here is to get rid of base metal so I can process like fingers.
I also need to know if I can put any non copper in this i.e. very small parts that are gold plated over tin or iron , or if even small amount would cause problems.

As a side note , the first time I tried to recover gold I used a whole bunch of old stuff, 486, 386, gold capped military stuff.... Lost almost all of it but about 1/2 gram due to Shor international instructions with their sub zero. Tossed it all in aqua and it made a sludge of green paint etc and Although I did get some back I lost most of that trying to melt it as it blew away, and the rest I find out later is locked in solution with the tin that unfortunately I tossed out . I do actually have a little of that left from '06 . I added water and tossed in a spoon. I have not figured out yet how to recover anything from this. Was just told to put stainless steel in.

I will start another thread on an interesting thing of gold flakes from fingers dissolved in lye water.

Bear in mind that I am still learning, and not put this into practise yet. Lye dissolves aluminium, tin and lead (quite vigorously) which would take away the solder and leave precious metals in the solid residue along with all the chips that fall off.

I had it confirmed by a fellow refiner with experience who currently uses this method.

Im a tight-wad and a bit wary of fumes so it seems ideal for me. BE WARY, the reactions could be vigorous especially with aluminium. Im hoping to experiment with it next week to see if the process suits my purpose.

I have posted on here asking why nobody seems to use this much cheaper much less toxic method of depopulating the boards than HCL bath, and nobody has responded .

Lye is a very dangerous chemical. Many people take it as being less dangerous because it is not labeled "acid". With a bit of reading you will find that many base chemicals have serious hazards, often more dangerous than the acids we use.

I would like to learn how the use of lye is less toxic in refining. Can you point us to a good text on it's use?

Another point is that of the waste clean up. If you use only one or two chemicals the waste treatment can be better streamlined to meet your specific needs. Bases often need treating separately from acid type chemical.

There is much still to be learned. Keep studying you will get there.

I use simple heat to de-populate boards, then soak in cheap Hcl to remove the tin solder. Makes recovery of the gold easier and cleaner gold.

Shark said:

Lye is a very dangerous chemical. Many people take it as being less dangerous because it is not labeled "acid". With a bit of reading you will find that many base chemicals have serious hazards, often more dangerous than the acids we use.

I would like to learn how the use of lye is less toxic in refining. Can you point us to a good text on it's use?

Another point is that of the waste clean up. If you use only one or two chemicals the waste treatment can be better streamlined to meet your specific needs. Bases often need treating separately from acid type chemical.

There is much still to be learned. Keep studying you will get there.

Click to expand...

Thanks for your reply.

Assuming that you have the safety gear on- gloves/gauntlets, apron as you would for HCL, Na0H reacts giving off hydrogen- non toxic.

Left in the open it decomposes to washing soda.

Assuming your boards are lead free, the resulting aluminium hydroxide, tin hydroxide are non toxic and used by waterboards in purification plants, the solution can be relivened by electrolysis or addition of slaked lime.

Lye is 10% of the cost of hcl here. HCL dissolving tin creates highly toxic stannous chloride.

So yes, it does seem safer for the environment and wallet provided proper precautions are taken.

http://www.practicalmachinist.com/v...droxide-caustic-soda-lye-useful-stuff-158041/

Starting to feel that HCL is being used because its the way it has always been done.

clearsteam said:

Shark said:

Lye is a very dangerous chemical. Many people take it as being less dangerous because it is not labeled "acid". With a bit of reading you will find that many base chemicals have serious hazards, often more dangerous than the acids we use.

I would like to learn how the use of lye is less toxic in refining. Can you point us to a good text on it's use?

Another point is that of the waste clean up. If you use only one or two chemicals the waste treatment can be better streamlined to meet your specific needs. Bases often need treating separately from acid type chemical.

There is much still to be learned. Keep studying you will get there.

Click to expand...

Thanks for your reply.

Assuming that you have the safety gear on- gloves/gauntlets, apron as you would for HCL, Na0H reacts giving off hydrogen- non toxic.

Left in the open it decomposes to washing soda.

Assuming your boards are lead free, the resulting aluminium hydroxide, tin hydroxide are non toxic and used by waterboards in purification plants, the solution can be relivened by electrolysis or addition of slaked lime.

Lye is 10% of the cost of hcl here. HCL dissolving tin creates highly toxic stannous chloride.

So yes, it does seem safer for the environment and wallet provided proper precautions are taken.

http://www.practicalmachinist.com/v...droxide-caustic-soda-lye-useful-stuff-158041/

Starting to feel that HCL is being used because its the way it has always been done.

Click to expand...

So, you've been doing this for exactly 3 weeks, today. I've been doing it for 50 years and I still don't like the dangers involved in working with sodium hydroxide. It's far, far safer working with HCl. I don't buy anything you just said. As far as I'm concerned, the 2 most dangerous chemicals we use are concentrated sulfuric acid and strong sodium hydroxide solutions. Both increase 10 fold in being dangerous when they are hot. Maybe, when you've been working with these chemicals, daily, for 4 or 5 years and after making 500 posts, you'll be qualified to make valid suggestions that will get no one hurt.

acid/alkali , both need to be treated with respect, both can muck your life up.

one is sold over the counter everywhere, the other is limited to chemical and building supplier, which is the most dangerous do you think?

I think you're maybe kicking yourself for having caused so much toxic waste with HCL and all the dollars going down the drain.

I have been on the forum for three weeks,been dismantling and recovering gold from IT for nearly six months without attempting processing (other than small experiments), researched papers and methods outside of this site, I like to get to source material and information, and a few months after the research began I found this great site where people share their practical experiences as they learn. This is a VERY VERY useful resource and methods are constantly developing, such as the AP process.I did study chemistry thirty years ago band and live a life by logic and tradition, some traditions have been lost, and some seem set in stone that perhaps shouldnt be as the nature of the ores you are working with change.

I may be wrong, but experiment is the only way to prove it

clearsteam said:

Bear in mind that I am still learning, and not put this into practise yet. Lye dissolves aluminium, tin and lead (quite vigorously) which would take away the solder and leave precious metals in the solid residue along with all the chips that fall off.

I had it confirmed by a fellow refiner with experience who currently uses this method.

Im a tight-wad and a bit wary of fumes so it seems ideal for me. BE WARY, the reactions could be vigorous especially with aluminium. Im hoping to experiment with it next week to see if the process suits my purpose.

I have posted on here asking why nobody seems to use this much cheaper much less toxic method of depopulating the boards than HCL bath, and nobody has responded .

Click to expand...

Lye is strong stuff. I used it a lot over the years for other things. I soaked boards in very strong solution to remove solder mask without heating but never had it eat away at anything else.
Solder mask removes at 20% with heat so perhaps a stronger maybe 50% and heat is needed to attack metals.
In another thread I posted today you can find what happened to a freinds gold flakes with strong lye.

I will be cleaning some LNB boards soon and I will experiment with different moles of lye and heat to see what happens.

rickbb said:

I use simple heat to de-populate boards, then soak in cheap Hcl to remove the tin solder. Makes recovery of the gold easier and cleaner gold.

Click to expand...

That is what I am going for. I figured acid first to get rid of a lot of stuff then AP . Just was not sure about using AP first as I hear it is not great for base metals but then others say use it for pins .
I will go with HCl hot then AP then clorox. Well maybe AP twice with a good wash as I read earlier it is needed for pure gold .

Wish I would have known all this in 06 . Big chunk of gold gone .

I guess location may play a large part in it, but HCl can be bought off the shelf here in one of this countries largest retail chains, Wal-Mart. Lye is another story, quite often very hard, if not impossible to find on the shelf any more. I worked with lye on a large scale from the early 80's until around 2005. Believe me when I say it demands respect. The little bit of refining I have accomplished leads me to agree wholeheartedly with GSP, lye and sulfuric are two of the most dangerous chemicals we use. As for dollars down the drain, I am not to sure what you mean. My first two gallons of HCl was used to make up my AP somewhere around three years ago, and I am still using it. I use it less often these days, but I do still use it. With work and study you will find a lot of the chemicals can be used over when handled right.

markk said:

clearsteam said:

Bear in mind that I am still learning, and not put this into practise yet. Lye dissolves aluminium, tin and lead (quite vigorously) which would take away the solder and leave precious metals in the solid residue along with all the chips that fall off.

I had it confirmed by a fellow refiner with experience who currently uses this method.

Im a tight-wad and a bit wary of fumes so it seems ideal for me. BE WARY, the reactions could be vigorous especially with aluminium. Im hoping to experiment with it next week to see if the process suits my purpose.

I have posted on here asking why nobody seems to use this much cheaper much less toxic method of depopulating the boards than HCL bath, and nobody has responded .

Click to expand...

Lye is strong stuff. I used it a lot over the years for other things. I soaked boards in very strong solution to remove solder mask without heating but never had it eat away at anything else.
Solder mask removes at 20% with heat so perhaps a stronger maybe 50% and heat is needed to attack .
metals.
In another thread I posted today you can find what happened to a freinds gold flakes with strong lye.

I will be cleaning some LNB boards soon and I will experiment with different moles of lye and heat to see what happens.

Click to expand...

did you try depopulating boards with lye? I know it needs heat to speed up solder mask removal, but if left long enough the solder mask will dissolve anyway. the reaction with the solder should be more vigorous than the slow eating up of the mask. I do not want to heat any acid or base unless absolutely necessary (such as kovar pins). A vat of boiling acids/alkalis would require some serious serious safety precautions.

try mixing lye crystals with warm water to saturated solution, then add boards slowly , remove alu heatsinks , capacitors if possible to prevent too much fizzing. solder should be dissolved within a few days if not hours, residue in bottom of vessel should be mostly silver and a teensy proportion of the gold plate that had been dissolved in the solder.. (on top of the grit of mlccs and other tiny smds.)

I read your post abut lye dissolving gold.. you had not sinsed/removed the hcl, the na0H freed up the CL in the HCL to dissolve the gold, you have gold chloroaurate in solution, its still there, accidentally.

I must say as far as what I have used lye and acid for the lye is far more dangerous to play with. As far as refining goes I would not know which is less dangerous . To me dangerous is blowing up, burning me , deadly fumes... I have soaked in acid many times and the fumes dont bother me unless thick and all I know is lye getting on you is far worse. I am notorious for not wearing gloves. 10% lye does not bother me much but stronger does.

If thats the way you play then its best leave any chemicals alone and stick to salt and vinegar :wink:

clearsteam said:

If thats the way you play then its best leave any chemicals alone and stick to salt and vinegar :wink:

Click to expand...

well im still alive after many years of chemicals . Might be a bit damaged. I would not suggest using my methods of safety.

Does that salt and vinegar actually work ?

markk said:

clearsteam said:

If thats the way you play then its best leave any chemicals alone and stick to salt and vinegar :wink:

Click to expand...

well im still alive after many years of chemicals . Might be a bit damaged. I would not suggest using my methods of safety.

Does that salt and vinegar actually work ?

Click to expand...

Yes, it does.

https://www.youtube.com/watch?v=ouYW_7-Njbs sreetips (kadriver) has some really good videos

Normally, I'd say stay away from Youtube videos for gold refining, but there are a few members here that make them.

clearstream; I have not used the lye for anything but loosing up solder mask. I started with 40 mole I think it was and then just dumped in a bunch more. Used it cold just sitting in a bowl . Took a couple days and then I brushed off most of the green with a tooth brush. Then rinsed and dipped in vinegar to neutralize.
The boards were depopulated already. Never noticed it eating up any solder or doing any fizzing at all.
I depopulate with a large pair of wire cutters a small pair and a special pair of pliers and then cut all SMD off with a utility knife. Anything I dont want to ruin I use a desolder station. Heat gun keeps blowing fuses around this house so I dont use it any more.

That gold in lye , I think he said he just filtered it from the AP and it had paint in it so he pured straight lye over it in the filter. I dont remember but I think he said he poured water over that but it may have been the rest of the AP he was filtering .