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I should have mentioned that when you solder a copper wire to the steel Cathode Plate that the soldered connection and a porrtion of the wire insulation in close proximity needs to be sealed also. I suspect you'd already figured that was the case.
If you have some scrap copper water pipe that can be used as the Cathode as well. Real easy to work with.
Yes, this adventure will be one of your most interesting ones!
You'll be posting your updates and new adventures here for years to come!
Statistics: Posted by SeaMonkey — Sat May 23, 2009 3:39 am
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Silicone rubber is one choice. But how about one of the thicker varnishes? And what about making all the connections at base level and putting a thin even layer of epoxy all over the bottom of the container?
Steel for the negative electrodes gives me much more scope. I thought of narrow water pipe and a graphite centre electrode. Maybe three or four cut to the length of the graphite rod in glass jars.
Thanks for the info about the graphite found in alkaline and zinc/carbon. - I don't think I'll try to roll my own on this occasion.
I wanted to clean up the sides of the plates of those large 2 V cells. I used a steam gun and a screwdriver to prise out the asphalt. Then I suspended the cell by two bars through the connectors across two chairs. Then I heated it some more with the steam gun and worked the plates out.
The plates were shot to pieces, and I suddenly recalled it was the same when I took the plate assemblies out of the other one I had which I threw-out in bits a year or so back.
The neg plates were servicable but the positive plates were completely rotten and had mostly come apart at the top where they are attached to the connector. - It'll be the same story with the one remaining I have, It works to a degree but I don't think it'll be worth using it as a lead-acid battery.
Typical me, I put a crack in the top of the cell I pulled-apart tonight - but I think it can be fixed so it won't leak if I decide to use it for this project.
The plates were a devil to get out because they had swelled so much that the case was distended. There are deep scratches where the plastic spacers scraped as I prised the lid off with various screwdrivers and levers.
Statistics: Posted by mael — Fri May 22, 2009 3:43 pm
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For your initial small scale testing just wrap a couple of turns of bared copper wire around the end of a carbon rod, with the insulation brought close to the rod. Then seal it well with a thin layer of silicone rubber and let it cure overnight.
Your connections to steel may be soldered. You'll need to use some zinc chloride (acid flux) to do it and you'll probably find that at any hardware store where little kits of solder and flux are sold for putting copper water pipe together.
As you experiment on a small scale and see how things 'develop' you'll get some great ideas on how to enlarge and improve your design for serious gas production.
If you're able to find the carbon-zinc cells among the pile they'll have the carbon rods you want.
The alkaline cells won't have a carbon rod - inside those you'll find a small 'nail' shaped connection terminal implanted into a mass of powdered carbon and depolarizing oxidizer. The mix of powdered graphite and manganese dioxide is potentially useful but you'll have to pulverize it and re-compress it into a long, cylindrical form. If you know anyone that has a 10 ton (or more) hydraulic press and some suitably shaped mold to press it into then you can 'roll yer own!'
Once you've powdered the graphite/MnO2 lumps, thoroughly mix in just a wee bit of linseed oil (from the paint section of the hardware store) to make the powder slightly moist but not sticky. Then pack it into the cylindrical mold and press it down with extreme pressure. Withdraw the press and fill again with material and press again, and after several cycles you'll have built up a very solid rod that can be carefully extracted and left to cure in the air for several days.
To make it easier to mix in the linseed oil into the powdered carbon, you can mix it with paint thinner to reduce the viscosity. Then after you've mixed it into the carbon powder just let it air dry for an hour or so to let the paint thinner evaporate.
If desired, the material can also be pressed into flat, rectangular plates.
It's called hydraulic ramming. Very useful process.
You'll have great fun on this adventure!
Oh, by the way. With the alkaline cells, just peel away the outer casing and what remains of the zinc electrode on the outside of the carbon mass in the center, then rinse with water to remove any residual 'salts' and chemicals from the outside. You'll get the idea once you've torn into one or two of them.
Rollin' yer own is a superb experience!
Statistics: Posted by SeaMonkey — Thu May 21, 2009 7:10 pm
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Those graphite rods - I happen to know where about a thousand of small batteries have been left. I don't know how many of them are alkaline (with smaller rods), but I'm sure I'd find enough for what I want.
How would I connect a wire to a graphite rod?
* thread a SS screw in it?
* Wrap a coil or two of copper around the base and dip it in something tough and waterproof?
* Er ... ?
Graphite rods do seem to have some attractive qualities for an electrolyser and a good one is that they won't get eaten away.
* Sorry about the little typos here 'n there ... I always seem to mumble 'I wish I could edit' after I hit the send button.
Statistics: Posted by mael — Thu May 21, 2009 4:01 pm
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Some of the most efficient electrolyzers built (commercial) use ordinary steel for the Negative plates (Hydrogen liberating).
For the Positive plates Nickel plated steel is used. Nickel plating is needed for the positive plates to enable them to resist oxidation by the liberated Oxygen.
Carbon or Graphite works exceptionally well for either polarity and may also be used in combination with steel plates.
The old style carbon-zinc dry cells are an excellent source for carbon rods.
With a carbon rod as the central positive electrode mounted inside steel tube (such a conduit) which serves as the negative outer electrode; and insulated wire connections made to each then coated with silicone rubber, it is possible to make a 'plate array' of tubular design which works very well indeed.
The wooden box idea will work, but rather than asphalt line the inside with some heavy duty polyethylene such as heavy duty trash bags. The asphalt does work, and has been used in the past, but it isn't near as durable as the plastic lining. Epoxy paint may be another possibility.
For my small-scale experiments to test things I like to use grocery store glass or plastic jars. We've always got a steady supply of those.
Draining the electrolyte from a lead-acid battery is a great way to prepare it for a very long term storage which effectively puts it into a state of 'suspended animation.'
Your thoughts about constructing several low voltage cells in individual containers then series-connecting them to a higher voltage source is, in my experience, the most effective way to go about it.
Statistics: Posted by SeaMonkey — Thu May 21, 2009 2:59 pm
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With Jap stuff the first thing I normally do with a dead unit is to check the plug - that's probably 10 % of them fixed. Then go through the unit and check the parts which might get hot and a lot of them might only have a copper track eroded-away or a leg of a component is rattling where the solder used to be. And as you have found, the connection blocks are also a source of failure.
With Chinese stuff it could be anything.
Statistics: Posted by mael — Thu May 21, 2009 6:13 am
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T'is true that the second one I added to the first in series and put on charge had been empty for a couple of years and that this time I only added distilled water, but I can adjust the acid concentration myself. And if I pulse it until there's no more S left to liberate and have the electrolyte correctly diluted then I'll have two large cells for ... something.
The first cell hadn't been drained and after a few days the electrolyte registers around 1200. That's going to be a goer for sure with some pulsing instead of the DC charge it's on now.
* Last night I couldn't relax and sleep because I was thinking about this 2 litre/min unit I want. I have since long ago wondered about using my 1 litre honey jars. I think I might use ten jars with a few plates in each and run it off one of my hefty pulsers or the pulser through a couple of batteries or even straight DC. I've got to get hold of some sturdy material for caps, and I've got a 1cm thick acrylic sheet I cat use for that. I can cut it with a few tools I have at hand and if I go slowly I should cut it more than melt it. I can stick the circles on my drill stand and use it as a lathe so I can taper the disc to fit snugly into the glass jar. One good thing about a thick sheet like that is that I can thread it, and just in case my bubblers don't work then the cap should pop off rather than blow the sides out of the jar.
(I'm used to it) The other idea I had keeping me awake was using wood to make the electrolyser ... yes, "wood." If I had the cash I'd go and buy a commercial electrolyser. No! I'd buy two. I'd use one and take the other one to bits and learn its secrets and try to make it better and build another from ideas generated from examining it. - But I can't do that yet. What I can do though is to make pretty-much exactly the shape i want in wood, and I was wondering about sealing it with the 'paint' that is used on corrugated rooves - asphalt paint.
If I were to make an electrolyser from wood then I'd like to make it so I can plug it directly into the wall with a dimmer switch into a rectifier and a cap bank. That'd be simple, it'd consume little power, shouldn't get hot, and with (say) 50 cells running off whatever DC 100 V AC translates to, I'd likely be getting more gas than I'd usually use, and have lots to spare for perhaps trying to run an engine off.
What do you think?
Yes. The Japanese are certainly good with their engineering. Those water heaters with the pumps lawst a long time. I've got several of those pumps knocking about the place. With Japanese stuff I've found the electronics rarely give out. In those water heaters the seals might leak in the lid after 10 - 20 years, or the plastic used in the casing may crumble. But they can usually be fixed.
Not so the Chinese junk which has made some inroads here. I do not like opening the back of something made in China as it is obviously made by people who don't like their job - probably forced labour at some political prison.
Statistics: Posted by mael — Thu May 21, 2009 5:59 am
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Yes, the condensation from your dehumidifier is a suitable replacement for distilled water. If it looks pure and clear it will be fine.
You may want to re-consider dismantling those cells for their cases; they may be more useful to you as rejuvenated energy storage devices. I'd venture to guess that a period of time spent pulsing them would surely bring them back to life. And, with the clear case walls, you'll be able to observe dramatic changes in the plate colorations as the desulfating/charging restores the active materials. The positive plates will become nearly black in appearance while the negative plates will become grey. You'll also be able to see whatever bubbling may result during treatment and be able to make 'adjustments' to minimize it.
A lead acid battery in good condition will have an internal resistance of a few millOhms. A heavily sulfated battery will have an internal resistance as high as 2000 Ohms on occasion. Since a sulfated battery/cell is a special case of abnormally high resistance (DC impedance) a high voltage pulse is required to pierce the high resistance barrier in order to initiate sulfation reversal. As the battery begins to recover the high current pulses will produce much less voltage across the battery/cell because the decreasing resistance as it approaches good health will 'load' the pulses greatly.
While the impedance match during desulfation isn't ideal it isn't harmful to the battery unless the battery gets hot or gases excessively.
By the way, I've just 'repaired' one of those Japanese made (Tayama) electric hot water producing units with the little electric motor/water pump in the base and - wow! - they're ingenious little devices! I use it for making steaming hot water for our tea/coffee. It's several years old and a couple of months ago the pump motor stopped working. So, I finally took it apart to investigate and found everything to be in excellent condition with no real problems. Apparently the disconnection of the motor connector from the control board and replacing it was all it needed. Once it was re-assembled and tested it worked just like new again.
I removed the motor/pump unit and tore it apart to investigate the 'magnetic coupling' that you'd mentioned before and was amazed at how effective it was! Those things are really well made.
Statistics: Posted by SeaMonkey — Wed May 20, 2009 5:41 pm
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* I knew running 12 V into one cell was putting about 10 V too much into it.
I had known that with this electrolysis anything over 1,24 V was going to result in heat. But I wish I could calculate impedance so I can apply it to other devices I use.
* Would I be somewhere near right if I said that charging a car battery with matched impedance would mean the battery is charged as economically as possible, and that using my pulse-chargers, which have a severe impedance mismatch uses all that potential heat-making over-current to stress those sulphate crystals into submission? I mean:- is the impedance mismatch with my pulser a useful application of impedance mismatching?
On a positive note, you have now convinced me to stop pretending I can shove 12 V into one cell.
Now to look at those buck-converters.
.... 
Statistics: Posted by mael — Wed May 20, 2009 1:58 pm
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I think the ensible approach as far as the plate arrangements are concerned is to make all the plates the same size and to use SS threads, and washers with rubber washers wherenecessary.
I can drill holes in SS reasonably well these days. I find any narrow drill which can make a hole and then try a bigger one. I finish the job off with a SS countersinking bit, and if I need a very large hole then I'll torture that last 'bit' until it goes through.
I was wondering about my being lucky enough to find some flashing made of SS which I could cut into two long strips and wind in a spiral. Obviously the SS would be pretty flimsy if it can be bent like that, so if I did it that way I'd have to add quite a few connections along (across) the length. - I suppose I will use whatever I can get my hands on, and it might take some time.
Those 2 V cells are now both on charge (for curiosity's sake). And actually they are capable of chucking out a lot of amps. The plates are as you wondered, which is that they are not in too bad condition - basically intact. There're no bits in the well to speak of. It does seem a waste in a way. The plates are bulging quite a bit, and some of the sponge-lead is oozing out at the sides, but they are useable.
And that reminds me:- The second cell I hooked-up to test-charge last night was empty - I'd emptied the electrolyte at least two years ago. It was very discharged when I emptied it, so I think there's a lot of S there to go back to acid. Well I put water from my dehumidifier in it instead of bought distilled water. I appreciate the stuff I emptied-out of my dehumidifier isn't as free of impurities as something sold in the shops, but is it OK do you think?
Statistics: Posted by mael — Wed May 20, 2009 9:32 am
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