# What acid bath are you using on CPUs



## Paige (Apr 17, 2007)

I couldn't tell from your video if your were talking about the cell or maybe HCL bath,

Thank you.

Paige


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## lazersteve (Apr 17, 2007)

If you are referring to the MMX Cpu Core Removal video, then the acid bath I referenced was the acid-peroxide bath.


Steve


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## goldsilverpro (Apr 17, 2007)

Steve,

Have you ever used stronger peroxide in that method. Someone on this forum or the other forum mentioned a common source for 30% (100 volume, I think it's called) hydrogen peroxide. It's really powerful and, of course, takes a lot less. I've used it a lot over the years to jack up other chemical processes. It will causes burns, however, not unlike the sulfur burns from a match. You've got to be careful with it. It looks so innocent.


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## lazersteve (Apr 17, 2007)

Chris,

I haven't ever got my hands on anything more powerful. There are some stronger concentrations available at health food stores, but I'm not sure of the actual percentage. The stronger stuff has more strict shipping regulations as well. The 3% works fine for me. As you probably know peroxide has some explosion hazards in the higher concentrations as well. I believe it has to be more concentrated than 30%, but I can't recall the actual level off the top of my head. I'm sure google could provide more accurate info. It would be nice to have a more concentrated supply to reduce the required stock volume.

Steve


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## Paige (Apr 18, 2007)

Steve,

Was that peroxide and HCL?

Paige


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## lazersteve (Apr 18, 2007)

Yes. 3% Hydrogren Peroxide, the household variety.

The mix is slow to attack gold and therefore works good to strip gold from base metals (it eats the base metals faster) such as in fingers, pins, cpus, and boards. It's not fast, but it is effective and safe to use indoors with minimal ventilation. You don't have to babysit it like you do AR. I personally will give up speed for safety any day of the week.

Steve


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## goldsilverpro (Apr 18, 2007)

It's probably hard for most people to understand this but, to me, the use of 3% peroxide is way too limiting. As I understand it, it takes 2 or 3 days or, whatever, for the HCl/H2O2 or H2SO4/H2O2 to do the job. If you always use 3%, you'll never be able to do it faster. That would drive me nuts, knowing that there's stronger stuff out there that might speed things up 4 or 5 times. If you had something stronger, you would be the master of the situation, rather than giving that distinction to the peroxide. You could adjust it to almost any speed you wanted, within much wider limits. 

I noticed on the web that Clairol makes a 12% hydrogen peroxide that is sold in beauty supply stores.


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## lazersteve (Apr 18, 2007)

Chris,

I've been toying with the idea of getting some high "proof" peroxide, but I haven't put the effort into it that I should have. I have lots of patience as there is always something to do while I wait. I'll look into getting some concentrated stuff and give it a whirl. 

Steve


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## Paige (Apr 19, 2007)

What about running chlorine through your AR?

Paige


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## lazersteve (Apr 19, 2007)

Why would you want to do this? Chlorine isn't very soluble in aqueous (water based) solutions, so if you tried to put chlorine gas in the AR it would likely form a cloud of toxic chlorine and not remain in the AR especially if hot. AR is plenty strong and hazardous enough on it's own with adding the chlorine.

Steve


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## rainmaker (Apr 22, 2007)

Ok, I'm fairly new at this, and really appreciate this site. What are the ratios of Peroxide and HCl for the acid bath? I know you probibly have this posted somewhere, but I haven't been able to find it. 

Thanks

Gary


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## lazersteve (Apr 22, 2007)

Here's the chart which shows the ratios for dissolving gold:







To attack the base metals and leave the gold foil/flake I use 2 parts muratic to 1 part peroxide 3% (1/2 gallon muratic to 1 quart peroxide).

Steve


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## Paige (Apr 25, 2007)

How about an index as to what those chemical abbreviations mean?

Thanks.

Paige


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## lazersteve (Apr 25, 2007)

Here's the quick down and dirty:

HCl 32wt.% = Muratic acid
MnO2= Manganese Dioxide
(s) = solid
atm = standard atmospheric pressure (15 psi)
NaCN = Sodium Cyanide (



)
M = Molar (Moles per liter)
Ca(OH)2 = Calcium Hydroxide (lime, quicklime)
NaOH = Sodium Hydroxide (lye, caustic soda)
Cl2 (satd.) = Saturated chlorine solution (see my Auric Chloride tutorial to make this)
HNO3 = Nitric Acid
g =gram
cm2 = square centimeter
h =hour

Did I miss anything?


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## AuMINIMayhem (Apr 26, 2007)

Steve, I tried the HCL mix tonight on some stuff. I noticed a slight exothermic reaction after adding material to it. Just thought it might be worth making note of as I was using the weaker solution and a stronger concentrated solution, I would imagine, have a much stronger reaction. Just a thought.. thanks for pointing me in this direction from the other post I made. 8) 
Derek


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## lazersteve (Apr 26, 2007)

Derek,

I've added some more detail for some other members.. it looks like I should do a tutorial on this one some day. I'm way past due on completing my karat gold cell.

Oh well, here's the link:

http://goldrefiningforum.com/phpBB3/viewtopic.php?p=2782&highlight=#2782

There's nothing like chasing around this forum for you guys! :lol: 

Steve


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## AuMINIMayhem (Apr 26, 2007)

lazersteve said:


> There's nothing like chasing around this forum for you guys! :lol: Steve



*pissing myself laughing* :lol: :lol: 

YOU?!.. hell, _*I'm*_ the newbie here.. :lol:


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## walter (Oct 20, 2007)

I have read in or two pyro forums that you can increase the strength of your h202 by boiling as it evaporates slower than the water.
just my 2 cents


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## Anonymous (Dec 22, 2007)

You can easily obtain 30% H2O2. Just go to a pool supply store. It is sold in gallons as pool clarifier.


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## aflacglobal (Dec 22, 2007)

Welcome to the forum Guns.


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## tlcarrig (May 10, 2008)

Baquacil oxidizer = 27% H2O2. Pool supply stores. Found easily and cheaper on the internet. Can be shipped by UPS or FedEx.

Steve, in your video on processing fingers in AP, you use 2 quarts of muratic and one quart of H2O2. Is it necessary to use this much solution for 60 grams of fingers? How much solution would you suggest for 60 grams of pins? Also, I have some very small pins that are really hard to get out of the plastic. What would I run into if I just go ahead and put the plastic in the AP solution? I know I would do this separately from my clean pins.


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## lazersteve (May 10, 2008)

I would do a single header with the pins intact just to test the AP reaction with the plastic. I've had good results running AP with the black plastic headers with the partially plated pins intact.

For small batches of AP follow this simple outline. 

1) Cover the scrap with twice it's volume of HCl.

2) Add 1/2 as much H2O2 as you used HCl, in four separate additions. Each addition should be at least 20 minutes apart or longer if the solution is still hot and bubbling from the previous addition.

Steve


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## tlcarrig (May 10, 2008)

Now we are getting somewhere. Your second sentence in #2 is something I haven't seen on here before. I will add this to my routine. Now, help me with this. I have 27% H2O2. To cut that to 3%, what amount of 27% would I use to make, say, 1000ml of 3%? The way I'm figuring, I come up with 9ml in 991 ml of water. If i'm wrong, don't laff too hard. Its been a long time since any math like this.


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## lazersteve (May 10, 2008)

You will get close enough for government work with :

110 mL 27% Hydrogen Peroxide + 890 mL H2O.

This should make 1L of roughly 3% peroxide if my calculations are correct.

Steve


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## tlcarrig (May 11, 2008)

Thanks Steve. I'll trust your figures over mine. Is there a chance that there are any other PMs in pins besides gold? I'm going to go through mine and snip off anything that is not gold plated. That will take a lot of the solder out of the mix. I know this will be time consuming but I have plenty of that.


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## tlcarrig (May 12, 2008)

Ok Steve, or anyone else, here's another one. I processed off my fingers per your video using 1500 ml of muratic and 800 ml of drugstore H2O2. The fingers came off just fine but they went into the solution. Now I have a solution of copper, solder and gold plus who knows what else. What next? What will drop if I go ahead with my SMB? I have not filtered yet. I think something has already dropped as there seems to be some kind of precipitate on the bottom of my container. I want to get this process down correctly before I start on my pins. One thing at a time.


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## Rag and Bone (May 12, 2008)

The precipitate should be gold. Check the solution with stannous chloride to see if any gold is still in solution.


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## tlcarrig (May 12, 2008)

Ok but I need to find out how to do that correctly. I have stannous available. I don't know about the precip. It's very light in color. It's the same color as the solution or white. The solution is lime green to yellow green and its hard to tell that there is a precip unless it is stirred up then the solution gets clowdy. I'll find out the correct way to check with stannous then go from there. One step at a time. Thanks Rag.


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## Rag and Bone (May 12, 2008)

If the solution is very clear and all your gold is stripped/precipitated, it sounds like you used way too much solution for the project. I keep reading posts about gold going into solution in AP. I never had that problem (until I nuked a few batches with concentrated H2O2). I wonder if people are stripping small amounts of fingers with lots of AP... 

I really don't see any reason to strip less than a couple pounds of fingers in a batch. Unless you're just starting out, in wich case: FOLLOW STEVES AP VIDEOS TO A T.


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## tlcarrig (May 14, 2008)

Rag, I'll have to agree with you. Too much solution. I processed 6 memory boards and maybe a dozen finger boards. I have about 1.5 quarts of solution. But, Steve used at least 2 quarts of muratic and 1 quart of H2O2 in processing 60 grams of fingers in his video. I have tested and there is gold in the solution. Now, how to proceed? There is copper, what ever the solder was made of (tin, antimony, lead, ??) and possably some dissolved electronic components. I am very tempted to go ahead and throw my pins in there but I don't want to add any other elements to the mix. Any suggestions are welcomed.


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## Rag and Bone (May 14, 2008)

I think it was 600 grams in steves video. At least, thats what I started with and I learned from the videos. 

My suggestion, don't worry about the gold in solution. Filter whatever solids you have. Then start a new batch with the same solution. 

For the amount of fingers you described, you could probably strip them in less than 1 cup af AP.


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## tlcarrig (May 14, 2008)

You're right Rag. It was 600 grams. I thought it was 60. Ok, I'll filter out the solids and use the same solution to process my pins. I'm just wondering what to use to get the trash (copper, tin, etc.) out of the solution so I can drop my gold with SMB.

On edit: My stannous test does indicate gold in the solution.


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