Thread: Electrolysis using an old computer power supply

Originally Posted by harty69

Hi bobl
having used stainless steel as electrodes for quite some time before switching to lead i can tell you they do visibly erode all though much slower than mild steel

cheers
Harty

OK - that's worth knowing - I'll do the experiment and get back to you when I'm done.

Originally Posted by harty69

Hi bobl
having used stainless steel as electrodes for quite some time before switching to lead i can tell you they do visibly erode all though much slower than mild steel

cheers
Harty

Hi Harty and All,
The thought occurs to me that you may and I emphasise may, be loosing lead too, but just haven't picked it up yet. If it were to go into solution, or drop out as a sludge, or even plate out in minute amounts, and if they didn't bond to the cathode work-piece, and just fell off when rinsing the item off at the end of the process we could be in blissful ignorance of what is going on. There is also the possibility in my head at least, if not in practise, that in the case of stainless steel anodes, which are loosing mass as they are used, that maybe the chromium is not being consumed, but perhaps the iron component of the stainless. The chrome may be being left behind, or it could also be transferred to the working solution as a sludge in the bottom of the electrolyte tank, so if you are in a position to determine what is going on BobL, you would be doing us a great service by passing on the result of your observations. Thanks to all participants, for your contributions to this thread, Regards,
Rob.

Hi Rob

I have had a close look at the lead sheets I use and there is some signs of erosion the sheets have been in use for around 5 years now and get used regularly say once a month for 4 hours at a time

cheers
Harty

Thanks Harty, probably what needs to be done now is for Bob-L or someone else with the knowledge and the facilities, to do some rigourous testing, and checking to see just what is being formed so that we know where we stand. Perhaps there are particular electrolytes which can be used which greatly diminish the formation of chromium compounds, or will form compounds which are much less troublesome, or perhaps we can change the process in some way to engineer out the problem. Not trying to railroad you into doing the hard yards Bob but you did kind of volunteer to do some of it.
Either sheet forms of carbon or graphite are looking better all the time, because as far as I know, there will be no issues using graphite except the production of Hydrogen, which isn't really a problem with any basic ventilation system. Cheers,
Rob.

Originally Posted by Ropetangler

Thanks Harty, probably what needs to be done now is for Bob-L or someone else with the knowledge and the facilities, to do some rigourous testing, and checking to see just what is being formed so that we know where we stand. Perhaps there are particular electrolytes which can be used which greatly diminish the formation of chromium compounds, or will form compounds which are much less troublesome, or perhaps we can change the process in some way to engineer out the problem. Not trying to railroad you into doing the hard yards Bob but you did kind of volunteer to do some of it.
Either sheet forms of carbon or graphite are looking better all the time, because as far as I know, there will be no issues using graphite except the production of Hydrogen, which isn't really a problem with any basic ventilation system. Cheers,
Rob.

I'm taking some holidays in two weeks time - I'll give it a crack them. I can't see how one can inhibit the formation of Cr compounds otherwise the Cr plating boys would be using it.

This is a pretty damning parapgraph from wikipedia. Don't forget this is for a Cr plating bath which is a concentrated Cr solution whereas rust removal by electrolysis using SS is unlikely to generate a concentrated Cr Solution.

"From a health standpoint, hexavalent chromium is the most toxic form of chromium. In the U.S. it is heavily regulated by the Environmental Protection Agency (EPA); the EPA lists it as a hazardous air pollutant because it is a human carcinogen, a "priority pollutant" under the Clean Water Act, and a "hazardous constituent" under the Resource Conservation and Recovery Act. Due to the low cathodic efficiency and high solution viscosity a mist of water and hexavalent chromium is released from the bath, which is toxic. To control these emissions wet scrubbers are used. The discharge from the wet scrubbers is then treated to precipitate the chromium from the solution, because it cannot be discarded in the waste water.[2]
Maintaining a bath surface tension less than 35 dynes/cm requires frequent cycle of treating the bath by a wetting agent and confirming the effect on surface tension.[3] Traditionally surface tension is measured by a stalagmometer. This method is, however, tedious and suffers from inaccuracy (errors up 22 dynes/cm has been reported), and is dependent on user's experience and capabilities.[4]
Additional toxic waste that is created from hexavalent chromium baths include lead chromates which form in the bath because lead anodes are used. Barium is also used to control the sulfate concentration, which leads to the formation of barium sulfate, a hazardous waste.[2]"

To me this means don't run an electrolysis unit using a SS electrode inside a shed or room where you spend a lot of time. There is still a problem of what to do with the electrolyte when you have finished. It sounds like Carbon is the go.

Originally Posted by BobL

To me this means don't run an electrolysis unit using a SS electrode inside a shed or room where you spend a lot of time. There is still a problem of what to do with the electrolyte when you have finished. It sounds like Carbon is the go.

Quite a few years ago I made a post on electrolysis safety with regard to hexavalent chromium. I posted a couple of links to information about it to inform people about it, admittedly, not as scholarly as 'Wikipedia'. I was roundly criticised for mentioning it. Well I assume I was criticised for mentioning it, because I did not say anything else, such as "you backyarders should not do electrolysis", for which I could have been criticised. I felt badly done by for a while about that, but this thread reminded me of it when I went searching for the old links to post here.

Here is the link, although the links within are now dead.


Makes interesting reading in light of you current position, Bob. I didn't say any more than what you have in your last post. (_*_)

Originally Posted by mic-d

Quite a few years ago I made a post on electrolysis safety with regard to hexavalent chromium. I posted a couple of links to information about it to inform people about it, admittedly, not as scholarly as 'Wikipedia'. I was roundly criticised for mentioning it. Well I assume I was criticised for mentioning it, because I did not say anything else, such as "you backyarders should not do electrolysis", for which I could have been criticised. I felt badly done by for a while about that, but this thread reminded me of it when I went searching for the old links to post here.

Here is the link, although the links within are now dead.


Makes interesting reading in light of you current position, Bob. I didn't say any more than what you have in your last post. (_*_)

My reading of that thread was it was more about H and O generation issues than Cr but whatever the case I'm sorry about my tone in my posts - I must have had a run in with OSH people at work or got out of the wrong side of the bed - I agree that it's always better in the first instance to be cautious than not.

One thing I perhaps did not stress in my last post was the Wiki information refers to Cr plating where large baths of concentrated Cr solutions are exposed to air. In terms of what back yarders breath in, there will be a very significant difference between the amount of Cr(VI) generation in a commercial plating operation that runs 24/7/365, and 12 hours of electrolysis a few times a year in a small bath of Na2CO3 and a SS electrode, especially if it is done outside.

There does remain the issue of what one does with the solution - but one thing no one seems to know is how much Cr even ends up in the solution. If it turns out to be X g/L and by dilution with a reasonable amount of water it can be brought down to a level close to that acceptable in drinking water then disposal is a non-issue. This is likely to only be possible by using small baths. I will investigate. The other method of disposal is that suggested by Major Panic in that thread.

The cross over area is probably where home electrolysis moves from a couple of items a year in half a bucket of solution to a dozen+ items a year in a 50L drum that runs often continuously in a shed. In this case I would say it definitely pays to be cautious until the situation is better understood.

I am also a firm believer in substitution - if a source of Carbon rod or sheet is available I would say use that first especially if a user moves into the cross over area.

Originally Posted by BobL

My reading of that thread was it was more about H and O generation issues than Cr but whatever the case I'm sorry about my tone in my posts - I must have had a run in with OSH people at work or got out of the wrong side of the bed - I agree that it's always better in the first instance to be cautious than not.

Bollocks Bob, it was never about the hydrogen/oxygen problem. Those links were about Cr, and the post began by raising this as the issue. The H/O was just mentioned by the by as a footnote.
edit. Anyway, I'm glad you have taken a more safety-prudent position, let's move on.

Originally Posted by mic-d

Bollocks Bob, it was never about the hydrogen/oxygen problem. Those links were about Cr, and the post began by raising this as the issue. The H/O was just mentioned by the by as a footnote.
edit. Anyway, I'm glad you have taken a more safety-prudent position, let's move on.

I guess it shows I didn't read the links or maybe even the posts but made the unreasonable assumption that it was about concern over H&O. Yes I have definitely taken a more safety prudent position especially for anything bigger than a half bucket.

Ahem.

If someone buys a box of 50 carbon electrodes, I would be happy to buy say 6 or 10 for the cost plus postage. I'll even do the buying if I can sell off the surplus (I just can't see the need to have more than that number for the small amount of electrolysis that I do).

Originally Posted by mic-d

Ahem.

Originally Posted by jmk89

If someone buys a box of 50 carbon electrodes, I would be happy to buy say 6 or 10 for the cost plus postage. I'll even do the buying if I can sell off the surplus (I just can't see the need to have more than that number for the small amount of electrolysis that I do).

What about something like this from a lab supplier?

This mob are about the cheapest I could find, and much, much cheaper than an Australian supplier.

I'd be interested in 10 Carbon Rods if there is a bulk buy, and offer Admin assistance to facilitate the same if required.