Cathodic cleaning.

[T i m]

We (even the Mrs) are all finding it quite fascinating. How you can put something in what is basically water and pull it out a while later looking a lot lot better and with no noise, real effort, chemicals (in the nasty acid sense), much cost or risk so we are still waiting for the gotcha. That and the soda concentration doesn't dilute or deplete with use apparently etc etc ... ? ;-)

Same here, or more difficult to access (inside stuff) than intricate as such.

I guess it's something I've just done since I can remember.

My first cycle was found in a ditch all overgrown and recovered, handed in to the police station, collected 6 weeks later and 'restored'. I think used it for school and a couple of cycling trips. ;-)

I've picked up mopeds in wheelbarrows, brought half motorbikes home, half on their own wheels and the other half on my (home made) go/box-cart and bought cheap / been given many a motor vehicle in a sorry state and brought them back to life.

The most visually effective was an old but low mileage MZ ETZ 251 Saxon Tour that got caught up in a Bike Shop fire and I was given once it had been written off under their insurance.

about 200 quid in second hand parts and I ran it for about 6 months till a mate needed a bike and I needed some cash. The last pic shows it after a couple of weeks and awaiting the new seat cover.

40k+ miles later he offered it to my daughter on the grounds that if she could start and ride it it was hers for nowt.

She even prefers it's new colour scheme. ;-)

took the screen off though because (apparently) they are for sissy's (he says looking at the very large screen and fairing on his old BMW boxer). Doh! ;-)

Cheers, T i m

p.s. When I was IT training in the city a fellow instructor was from South Africa (although he was born and lived in Scotland for many years) leaving his family over there whilst trying to set up a new home for them all over here. He was going though a bit of a bad patch and through conversation it turned out he had been a biker years before so I asked him if he would like to join us for a long weekend motorcycle camping. I put him on the MZ insurance, dug out some spare bike kit, tent and sleeping bag and after some initial checks to make sure he still had the knack we set off!

It was really nice to see him forget all about his 'problems' for a few days and he even found the MZ to be a fun little ride. His backside wasn't up to 200 mile days on the MZ saddle though. (Apparently his night vision was about as good as the MZ headlight so after dusk he would just follow the lights on the trailer behind my bike. ;-) )

[T i m]

I may have an old stainless sink on it's way (if his Mrs hasn't already thrown it out). I also know someone who works in a shop fitters on stainless units who may be able to save me some offcut / strips etc.

Another question though if I may (along those lines).

To give the drums another shot but with the focus on the insides I bought a low dustbin sized tub and found a (zinc?) plated / plastic coated (one side) side panel (Dexion shelving) in the workshop that was thin enough to sorta hand roll to sit on-edge inside the bottom / sides of said tub like a lining (zinc face inwards). I put the drums back to back in the middle on edge and drums facing outwards and then some plastic sink grid things either side to stop them rolling about but allow the process freely though them. Fresh batch of solution and the properly wired / fused second PSU and it's really going (the

20A blade type fuse holder was getting noticeably warm)!

Now, initially I didn't see any of the typical brown-sludge 'build up' on the inside of the sheet but when I clipped a couple of bits of chrome .. old PC case steel to the sheet they seemed to gunge up pretty quickly?

The question, does it 'matter' what the surface finish is of the anodes for this process or is it sufficient that they are just 'conductors' please?

Cheers, T i m

p.s. I did try a small strip of ally foil that I rolled over a few times and curved round the inside of one tub but it started to break down and float about in the soup. ;-(

[Andy Dingley]

I wouldn't run at more than 2A / sq ft. of surface. You can cause corrosion faster than you're de-rusting if you start getting electrolysis and too much obvious heating or bubbling.

It is useful to make up shaped anodes to fit inside some shapes. I mostly use old microwave or washing machine scrap, tinsnipped up and bent to shape - sometimes held or connected with stainless self tappers (don't use or trust aluminium pop rivets!). A supply of coarse plastic mesh (old laundry basket) can be handy too as an armature for shaping or hanging stuff from, or as spacers to stop accidental contacts.

Be aware of the waste issues (Erin Brockovich) if you use stainless anodes. Certainly take your anodes out of the tank when the power is off.

[Thomas Prufer]

As far as I know, they need to be a) conductors, first and most, and b) reasonably resistant to the oxygen produced. Might there have been some clear coat on the zinc?

You might bung an ammeter in the circuit. Ideally, a big round black thing with an elaborate pointer, mounted on a mahogany panel, next to a knife switch...

Thomas Prufer

[Alan Braggins]

On the other hand it potentially turns the electrolyte from something that can be safely dumped anywhere into a hazardous waste product requiring careful handling:

[T i m]

Check. ;-)

Not that I could see / feel. That said and with it running for longer this morning it is starting to (also) show signs of 'deposits' on the zinc covered stuff as well.

That certainly would be in keeping with this whole project!

No, I used a clip-n 75-0-75 Ammeter and that showed about 15A on the setup with said big panel (~3-4 sq feet) and the two drums.

Cheers again,

T i m

[geoff]

In message , T i m writes

And it has to be located in a castle on a hill just outside Darmstadt

>No, I used a clip-n 75-0-75 Ammeter and that showed about 15A on the

[T i m]

Is this single sided surface facing the cathode or total or what (please)?

Difficult for me to tell if it's 'too much' bubbling of course and it's only 'just' perceivably warmer than the other pot and a container of rainwater beside it.

I've just lifted the drums and I'd have to say they are much cleaner than previously, in fact there are now only a few patches of rust remaining whereas before it was just less rust all over.

Mate delivered their old stainless steel sink just now. I have set some old PC side panels and a spare bit off my garage steel doors (probably 1mm mild steel sheet)?

I was wondering what would stop us using the sink part as is as an anode (with a plastic basket within) then dandling smaller stuff into it on metal coat hangers from a bus bar? But if you say stainless can bring it's own special issues ... ;-(

Oh, more so than any / most other metals? What would be the least problematic metal for the anode would you say?

Because (they would erode and contaminate the fluid further)?

Cheers, T i m

[T i m]

Looks like I have a stainless steel sink to take down the scrappy's then. ;-)

Cheers, T i m

p.s. So, are we suggesting here that if we use certain metals as the anode in this process the resultant solution could still be deemed to be 'safe' to tip down the drain?

I was considering letting the liquid settle, siphoning off the clear liquid (to put down the drain?) then dispose of the sludge in newspaper in the bin?

p.p.s. So I guess this would also apply to using a chrome plated anode? (I had a couple of bits out of an old PC case that 'looked;' chromed but it may have been something else that was bright?

[Andy Champ]

Most likely bright zinc plating if they were internal.

On the outside they might have been chrome for the bling.

Andy

[T i m]

Ok ta.

Not on one of my cases it wouldn't. ;-)

It was actually the remains of one of the first midi tower AT cases I ever bought when they were made out of steel and not tin. The empty case weighs as much as many PC's do now when full. ;-)

Once you took the standard inverted U style (beige) case off you could release a couple of latches and lift the front / top up a bit on some hinges and held up with a sliding stay, to allow you to get to stuff (cables / ram etc) easier.

I was going to cut the case up to make some anode plates but my tin snips wouldn't touch it!

Looking again all the inner chassis is very chromey ... I'll take a pic tomorrow.

I've just pulled the drums out of the soup and they are much much cleaner than before. I've just run a 240 grit w&d sponge block over the frictionable part and it's very much smoother. Still some pitting of course but hardly any lumps. And the inner races don't fall in place so there doesn't seem to be any major erosion. ;-)

Cheers, T i m

[Andy Dingley]

Workpiece area. I make the anode at least as big, usually a couple of times bigger.

You can adjust the current by adjusting the voltage (I don't), with a series resistance, or (easiest) by treating the tank as a liquid rheostat and adjusting the spacing or the soda concentration.

Small parts can be done in a stainless steel pan, with them held in either a plastic basket or (more usefully) a wire basket connected as the cathode. Use plastic spacers to keep them apart. This is a good way to handle bolts etc.

Iron or steel is least trouble, but it erodes. Stainless is simplest to use, but the sludge becomes a toxic hazard - chromium from electrolytic processes can be in the problematic forms. Zinc or copper plating will end up in the sludge too, but they're not especially hazardous.

Because they'll disappear! (Slowly, but they will gradually fall apart)

My tank has a rectangular frame above it of glued plastic conduit. There are also plastic S hooks (no idea where I got them) for hanging stuff from. If I'm not using it, I stick the electrodes and gubbenry up on the rack, out in the dry.

[T i m]

Ah, thanks for the clarification.

Understood. Do you go with the one teaspoon / pint concentration?

Ok thanks.

Ok. And sheet rather than bar to get a good surface area?

Ah, thanks. I'm thinking I might drain the tank(s) off into a 25l sealed container, via a fine paint filter to remove the lumps of stuff. Not because it's expensive but if it doesn't deplete with use then simply to reduce the (potentially toxic) waste?

Very sophisticated. ;-)

How long would /you/ generally give something as bad as the stuff of mine would you think please?

Cheers, T i m

[Andy Dingley]

I scoop the sludge out when I get a couple of centimetres. If I don't use the tank for a while and it all evaporates, I clean out the remainder. The brown sludge often has a visible yellow-green tinge to it from the chromium.

Concentration is vague, but it's about a handful of washing soda to my usual tank (big enough for woodworking tools). A bit more variable if I'm using a jury-rigged tank for something bigger.

I rarely do anything for less than a couple of days (sometimes rotating after a day, to avoid shadowing). Something like this would be at least a week. It's self-limiting, so I just let it get on with it.

[Thomas Prufer]

I've used aluminum mostly -- which should be safe as there's drain cleaners that oxidise aluminum... Also, I do this rarely, only when there's a nice tool that needs saving. Saw an "antique" dealer where all the old tools had been run over with a power wire brush, leaving a gleaming scratched finish. Blech.

Thomas Prufer

[T i m]

Ok thanks.

The first batch (from the trailer hubs and using round steel stock anodes) was just bright orange with bits in.

Going by the 1 tsp / pint I ended up with 250mg of soda (a big mug full). My tank took nearly 4 x 2 gallon watering cans to fill.

Ah. I was concerned about the comments about over-current and erosion but as I've not seen any sign of that as yet and these drums look cleaner every time I give them a session I may well put them back in for another go.

There is no rush on the trailer (his truck is currently in Scotland) so it wouldn't hurt to carry on experimenting.

Cheers, T i m

p.s. Even if it did ruin the hubs some new ones wouldn't be a 'bad thing' as such and still a lot cheaper than a new trailer. ;-)

These were slightly heavier duty (1100 v 1000) pair from eBay the other day:

it wasn't 'Local pickup' only and that the actual condition was unknown and we seem to be getting somewhere with our pair ... ;-)

[T i m]

Noted. ;-)

I think I might like to keep it plain uncoated iron / steel and I think I understand they produce the least polluting waste?

And that's probably going to be the case here ... and when you considered what many people dump in general (that we d-i-y'ers might repair, reuse n recycle) we are probably still up on the average. ;-)

I was thinking about what else I might be able to use it on. ;-)

Indeed. What a shame.

Cheers, T i m

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember NT saying something like:

Bollocks.

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Thomas Prufer saying something like:

Mahogany? Black slate, if you please.