# Sulphuric cell



## nickvc (Jun 15, 2010)

Been dying to have a play with this idea and recently got dumped with a batch of plated jewellery and GF.The cell was an easy done chore,got a mini rectifier and pyrex dishes and some lead sheet but i was struggling with how to strip reasonable quantities when i remembered something Steve had said about using stainless wires to suspend in the cell.Thinking ,which for me is unusual, I headed for a local Asian cash and carry where lo and behold I found a stainless wire mesh scoop for deep frying about 5 inches in diameter and 3 inches deep which seems made for the job.Tried it this afternoon and it seems to be holding up and at about $3 a throw im not to bothered if it only lasts for this job :lol:


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## lazersteve (Jun 15, 2010)

Copper mesh is a much better choice, but stainless will do the job if it's the right grade. 316 SS seems to do pretty well.

Steve


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## nickvc (Jun 15, 2010)

lazersteve said:


> Copper mesh is a much better choice, but stainless will do the job if it's the right grade. 316 SS seems to do pretty well.
> 
> Steve


Thanks Steve but wont the sulphuric attack the copper? This batch is a right mix of everything from plated steel,copper and brass,the copper plated material seems to strip fastest leaving that nice red colour which I assumed the sulphuric also stripped.


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## jimdoc (Jun 15, 2010)

I tried a stainless basket and it worked great until the screen broke through.It didn't take that long before the basket dropped out. You can probably re-screen the handle with copper, thats my plan.

Jim


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## jimdoc (Jun 15, 2010)

nickvc said:


> lazersteve said:
> 
> 
> > Copper mesh is a much better choice, but stainless will do the job if it's the right grade. 316 SS seems to do pretty well.
> ...




Concentrated sulphuric will not attack the copper, as it gets diluted it may.
Jim


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## philddreamer (Jun 15, 2010)

Or, as I learned the hard way, the acid gets too hot. :roll:


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## nickvc (Jun 15, 2010)

Thanks guys, the sulphuric wont get diluted (its 98%) so I hope its just the gold that will strip .Most of the material seems to have stripped pretty easy but the different carats of gold plating seem to behave differently so a second strip may be called for on some items but much easier and pleasant than using cyanide which unfortunately I can smell  This isnt a mesh either its a stainless wire basket and seems fairly robust but as I said at $3 who cares...


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## jimdoc (Jun 15, 2010)

nickvc said:


> Thanks guys, the sulphuric wont get diluted (its 98%) so I hope its just the gold that will strip .Most of the material seems to have stripped pretty easy but the different carats of gold plating seem to behave differently so a second strip may be called for on some items but much easier and pleasant than using cyanide which unfortunately I can smell  This isnt a mesh either its a stainless wire basket and seems fairly robust but as I said at $3 who cares...




My stainless basket looked strong also, until it gave way. Just a heads up so it doesn't plop down into the acid and splash you.

Jim


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## lazersteve (Jun 15, 2010)

nickvc said:


> ...the sulphuric wont get diluted (its 98%)..



Nick,

You should be aware that 98% sulfuric acid is very hungry to absorb water. It will literally pull water right out of the air if it is left uncovered. Be sure to cover your cell when it is not in use or you may find your 98% acid has mysteriously become diluted.

Please do be careful.

Steve


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## nickvc (Jun 16, 2010)

Thanks yet again guys and I will be cautious as there is no rush to do this as its been done as a favour for someone else. The scoop will be tested after each batch and the bath will be covered until the job is finished after which the sulphuric will be put back into a sealed acid container until its required again, im only messing with a couple of litres with the dish sitting inside a larger pyrex one just to be sure and i wear arm length gloves and stand away not over the cell.


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## Oz (Jun 16, 2010)

Nick,

Just so you understand what Steve is saying put some 98% sulfuric in a graduate cylinder and watch the volume grow over the time it is exposed to air. You will be surprised at the water volume it takes up even with so little surface area exposed to the atmosphere.


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## nickvc (Jun 16, 2010)

Thanks Oz and Steve for your concern but the sulphuric is now back in its container safely screwed down.I guess its affinity to water is why it burns your skin so badly like caustic soda? A very interesting experiment and i hope successful,the gold filled is not ideal for the cell i knew that but the parcel was so mixed it was hard to separate it all so any items that looked like it was still plated has gone in with the GF in dilute nitric to slowly digest,the scoop seems fine but i will give it a careful look over when I wash it off but as i said for $3 I,m not to bothered if its only bin worthy now.


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## dtectr (Jul 6, 2010)

i also used some SS mesh, from a sink strainer, to strip all but 7 pins from a 486 CPU before i removed the cap & stripped it in the cell (see photo). I then used it as a basket held by 2 alligator clip contacts with varied success to strip the beautiful square main CPU contacts. My concern is whether this material as it breaks down will contaminate the cell so that it cements or similar problem?

I fashioned a basket from (seems to be) nonreactive plastic with a series of slits around the lower portion and am using SS welding wire, non-flux core, for the contact. i used this on pins with varied success (i think i overloaded it). would use of this pose a problem or have any advantages over the crockpot?
thanks!


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## Barren Realms 007 (Jul 6, 2010)

dtectr said:


> i also used some SS mesh, from a sink strainer, to strip all but 7 pins from a 486 CPU before i removed the cap & stripped it in the cell (see photo). I then used it as a basket held by 2 alligator clip contacts with varied success to strip the beautiful square main CPU contacts. My concern is whether this material as it breaks down will contaminate the cell so that it cements or similar problem?
> 
> I fashioned a basket from (seems to be) nonreactive plastic with a series of slits around the lower portion and am using SS welding wire, non-flux core, for the contact. i used this on pins with varied success (i think i overloaded it). would use of this pose a problem or have any advantages over the crockpot?
> thanks!



If you will remove your center cap and the silicone wafer before you put it in the cell the gold from these areas will deplate as well.


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## dtectr (Jul 6, 2010)

Barren Realms 007 said:


> dtectr said:
> 
> 
> > i also used some SS mesh, from a sink strainer, to strip all but 7 pins from a 486 CPU before i removed the cap & stripped it in the cell (see photo). I then used it as a basket held by 2 alligator clip contacts with varied success to strip the beautiful square main CPU contacts. My concern is whether this material as it breaks down will contaminate the cell so that it cements or similar problem?
> ...


thanks for that, barren realms - i was thinking of trying that with the next ones i do. 
any thoughts about the mesh-thingy idea?


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## Barren Realms 007 (Jul 6, 2010)

dtectr said:


> Barren Realms 007 said:
> 
> 
> > dtectr said:
> ...



The SS mesh should work ok with little or no problem. I use a set of aligator clips and attach to the legs and deplate, I have this setting in a plastic pool pump strainer(that is setting in the cell, the strainer is very heavy and getting coated with gold and will have to be delt with. As long as you watch the temp in your solution and don't let it get hot or let water enter into the cell you should be ok to go.


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## dtectr (Jul 6, 2010)

Barren Realms 007 said:


> dtectr said:
> 
> 
> > Barren Realms 007 said:
> ...



Thanks, bud.


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## Harold_V (Jul 7, 2010)

jimdoc said:


> Concentrated sulphuric will not attack the copper, as it gets diluted it may.
> Jim


Diluted sulfuric is the pickling acid of choice for copper. It won't touch elemental copper, but readily dissolves copper oxide. That's the reason copper baskets are recommended for stripping cells. The original purpose in a stripping cell was for stripping expensive copper based parts that were good, but the plating wasn't. Stick with copper and you're doing as well as you can.
Copper will dissolve in concentrated, heated sulfuric. That condition shouldn't exist in a stripping cell. 

Harold


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## dtectr (Jul 10, 2010)

just a follow-up on my Stainless-wire-anode-in-plastic-bottle-thing - as steve elsewhere said could happen, extra heating of solution tends to happen more readily with special anodes, and it did with mine. 

also not all pins were in contact with the wire at the same time so some stripped slower than others, or just partially. i imagined that, in theory, if the pins were all in contact with each other & at least some were in contact with the anode that they would strip equally, but that does not seem to be true in practise.

i think i won't try to reinvent the wheel (where have i heard that before?) and stick with crockpot or A/P for pins & reserve cell for larger items like lids.

just FYI


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