Well, that went well, not!

**Ropetangler** · 27th November 2012, 10:42 PM

Hi there boys, I used an Arlec Charger4 as my P/S to clean up an old very rusty Leblond lathe bed about the same size as the one you are doing Ken, and I used an old headlight (from a car) as a current limiting resistor, to stop the bi-metal cutout operating. Here in Tasmania, I found that an indicated 4A would generally work continuously, but any higher and the P/S would cycle on and off, - slowly if you were ony marginally over the 4A, but quickly off and slow to recover if you had pinned the needle on the Ammeter. If you can lay your hands on some Graphite sheet, you will have great anode material as the carbon doesn't corrode, nor does it pass into solution, only to plate out on the item being de-rusted, like metallic anodes will. The only stuff I have seen on eBay was from overseas though, so unfortunately I have been unable to locate any locally. If anyone comes up with a local graphite supply, I will put my hand up for a couple of square feet if there is enough to go round, as always depending on price. Before I became aware of the potential for creating toxic chrome compounds, I used a stainless feed trough I made years ago when I had access to scrap stainless from the worn skins of the drums in a magnetic separation process line in an iron ore mine I worked at. I made the stainless trough the anode and had the lathe bed sitting on some polly pipe to insulate it from the trough. I had to do it in 2 goes, as my trough wasn't deep enough to fully submerge the LeBlond bed, so after a day or two, I rotated the bed 180 degrees, and gave it another day or so. It worked really well, stripped all the paint, even the stuff from the webbed section between the ways, and turned the bed from a heavily rusted item to one which looked nearly brand new. I did lightly go over the ways with a green kitchen Scotch pad. and used a pressure spray to remove any stubborn spots of paint, thinking back on that it may just have been the garden hose with a nozzle, if so then it would have been about 45psi maximum, but it blew all the last bits off.
That system worked well, better than I have been able to replicate using scrap iron bits as anode material, and perhaps because the anode fully surrounded the lathe bed, the action as quite even, much better result than I get using scrap iron junk as anodes. I asked questions of the local uni campus chemistry section, on how the hexavalent Chrome compounds might be prevented from forming, but could get no definite answer on whether it was possible to control the formation of these toxic compounds, by control of temperature, current density, temperature or any other variable. In the end I decided that I should play safe, and didn't make use of the trough as the anode, in spite of its obvious benefits
I too started by using caustic soda, and then went to washing soda, but no matter what you use, you need so little to make it work, I doubt that it would likely become a problem to dispose of, or to handle if you use caustic soda as your electrolyte. Just remember to use eye protection, especially if mixing up using hot water, in fact I would recommend using cold water for solution preparation using chemicals such as these, they will still get hot, as the material dissolves. Safety shields or goggles are only optional if you wont find blindness a problem in your life.
A suggestion for the tank might be a sheet of form ply used to build a box of suitable size, then varnished and finally fitted with some plastic sheet like forticon. Use sort stubs of poly pipe to lift the item above the base of the box and to prevent damage to the varnished plywood box. I hope that this gives some encouragement to you de-rusting people, but I found that it worked well for me. Cheers,
Rob

**jhovel** · 27th November 2012, 10:52 PM

A couple of years ago I electrolytically de-rusted a vintage motocycle exhaust system. The carbon deposits on the inside of the mufflers made that hard going. So I tried hot caustic soda and large electrodes. I connected my car battery to it with the car engine running. The mufflers were clean as a whistle inside and out in about 30 minutes and the car battery was flat. I estimate the current to have been around 70A or more. The jumper leads I used were too hot to touch and the car alternator was audibly working hard. The battery still went too flat to start the car again after the 30 minutes....
The steel mufflers came to no harm at all in the process.

**neksmerj** · 27th November 2012, 10:59 PM

Thanks RT for your experience.

This might encourage others to have a go at the electrolysis process, it does work!

Especially for smaller parts.

Ken

**Ueee** · 27th November 2012, 11:10 PM

With the graphite would the size rules still apply? (ie same surface area as part to be stripped)

STIRRING ROD GRAPHITE 16mm - FOR MIXING METAL WHILE MELTING | eBay

Graphite rod, in Aus too....

What about graphite slip cloth, the stuff you put on belt sander platens?

**Stustoys** · 27th November 2012, 11:13 PM

Hi Ken,
Sounds like it might do the job. Maybe a couple of props if it looks a little "iffy"

Hi Rob,
Would this suit?
Graphite Slip Cloth | The Sandpaper Man
I have some I can soak in little in water to see what happens if you'd like.

Stuart

**Ropetangler** · 28th November 2012, 12:02 AM

Hi again everyone,
Ewan I think that the rods would only work well for similar shaped items you were trying to clean up, but the graphite slip cloth that Stuart has volunteered to try out sounds well worth the time and effort to try. Try it in a working solution Stuart, just to be sure that the fabric backing that I presume that the slip cloth has, is not compromised by being wet in a strong alkaline solution. If it does work, it could be reasonably economical to use, and also convenient as it could be curved around the inside of the tank to fully surround the cathode which would help ensure an evenly cleaned surface. I would think that it is definitely worth trying for this purpose, and look forward to hearing the result.

Hi Joe, your solution must have just about boiled with the current going through that lot, Glad to hear it worked well though, - tell me was the exhaust system chrome plated ( or perhaps in those days nickel plated, or was it just black tube as a matter of interest? Regards to all,
Rob.

**Michael G** · 28th November 2012, 06:46 AM

Graphite is used for making electrodes for EDM machines these days so if you can find a toolmaking concern they may be able to point you in the right direction.

Michael

**Stustoys** · 28th November 2012, 12:26 PM

Reading through the thread again I found caustic, baking, bi-carb and washing sodas.
Does anyone have a favorite for the test?
Dishwasher powder is caustic isnt it? Woud that do?

-work, +graphite right?

Any current density you'd like me to aim for?

Stuart

p.s. Maybe I should see if I can get this stuff to conduct first. yeah should it should but does it?

**kwijibo99** · 28th November 2012, 01:22 PM

G'day All,
Just a couple of comments regarding paint, oil & grease and the electrolsys process.
If what you are trying to clean using electrolsys has any oil or grease on it the whole process will be severely inhibited.
For electrolsys to work the electrolyte, which is essentially water, needs to be in contact with what you are trying to de-rust, any oil on the surface will reduce or even prevent this contact from occuring. Give what you intend to clean a spray with the hose and look for places where the water doesn't stick, these will not de-rust properly.
If you use washing soda to make your electrolye then you get a bit of degreasing action but it's not much and you will still get uneven de-rusting.
If you use caustic soda to make your electrolye then you get a bit more of degreasing action but you will still get uneven de-rusting.
Either way your electrolyte won't last as long (assuming you want to use it more than once)
You will get much better results if you degrease what you want to de-rust before you put it in your electrolsys tank.
If what you are de-rusting is not oily but painted thats not really a problem because the painted bits generally wont be as rusty and the electrolsys process will remove the paint but it takes a while and sludges up your electrolyte.
I have always had good results on old parts with the following process, lets assume the part is greasy and still has some old paint:

Step 1: Trip to the local car wash and give your part a good pressure wash. (you might get some funny looks though)
Step 2: Place your part in a caustic bath. If using a bucket I use about a laundry scoop of caustic, if if its a big bit I use the wheelie bin and the same ratio of caustic that way it gets a clean too. If it's too big for the wheelie bin then it's off to the sand-blaster

. VERY IMPORTANT: put the caustic in first then add a kettle of boiling water SLOWLY at first, don't do this in your shed or you will find yourself doing a lot more de-rusting in the future. Wear a face shield, this stuff will burn you if it gets on your skin when its concentrated. I usually have a bottle of vinegar handy too because water won't help and can spread the burn. Fill the rest with cold water and don't forget to allow for the volume of your part so it doesnt overflow when you add it. The solution is less dangerous now but dont get it on yourself if you can avoid it and wash it off straight away if it does, you may not feel the burn straight away but it will still burn you. Put in your part and let it soak for a few hours or a day or even two days, depending on how thick the paint and oil is.
Step 4: When your bit is clean pull it out of the caustic, it should have a nice even coat of brown rust but no oil or paint. Give it a good hose and any remaining paint will usually wash off and even the brown rust will wash away.
Step 5: Fill a bucket with water and add a cup of vinegar (same ratio if you used a wheelie bin) and let your part soak over night. This step is particularly important if your part is cast iron and you intend to paint it. CI is like a sponge and will soak up the caustic which will cause your paint to bubble sooner or later if it's not neutralised.
Step 6: Remove your part and give it another hose. Dump the vinegar solution into the caustic solution (carefully) and they will neutralise each other before disposing of the liquid down the sewer, not the storm water, collect all the sludge in the bottom then bag it up and bin it. (Gotta be environmentally friendly ya know)
Step 7: Now go ahead with the electrolsys process. I only ever use bi-carb for the electrolyte and steel for the anode, it's cheap and plentiful. It doesnt matter how rusy the electrolyte gets you can use it over and over, I just top it up with water when it gets a bit low. After a while I just tip it out on the lawn which loves it and make up a new batch.
You should only need to run at a few amps and your part will be prefectly clean within a couple of hours.
Step 8: let it dry and if painting the part prime it right away, if not then give it a good rub with boiled linseed oil or steam cylinder oil if you can get any (Phil?) these are about the best things I've found for protecting raw iron.

If I'm not in a hurry I actually prefer to use molasis rather than electrolsys, it's just a personal thing it think but you just dump it in and forget about it for a month or so then pull it out and like magic it's clean.

Sorry about the long winded post, I just though it might be of some help.
Cheers,
Greg.

I

**Ueee** · 28th November 2012, 01:23 PM

Hi Stuart,
I don't think it matters all that much on what you use for the electrolyte, the main thing is that the cloth is conductive and doesn't just fall apart. - to work + to graphite is right. Aim for the highest amps you can, that should put it through the most electrical stress.

**neksmerj** · 28th November 2012, 03:41 PM

I undercoated my Hercus lathe bed, inside and out, before getting to get a colour chart to match the red inside the casting.

BT, if you are listening, can you tell me a close colour, I know you have Dulux colour swatches at work.

Ken

**Ropetangler** · 28th November 2012, 04:08 PM

Originally Posted by kwijibo99

Step 2: Place your part in a caustic bath. If using a bucket I use about a laundry scoop of caustic, if if its a big bit I use the wheelie bin and the same ratio of caustic that way it gets a clean too. If it's too big for the wheelie bin then it's off to the sand-blaster

. VERY IMPORTANT: put the caustic in first then add a kettle of boiling water SLOWLY at first, don't do this in your shed or you will find yourself doing a lot more de-rusting in the future. Wear a face shield, this stuff will burn you if it gets on your skin when its concentrated. I usually have a bottle of vinegar handy too because water won't help and can spread the burn.
Cheers,
Greg.

I

Hi Greg and others,
You raise some good points Greg, I agree that de-greasing and cleaning of parts before de-rusting is a good idea, it keeps the electrolyte cleaner for longer, and should make for a more even rust removal process, but having said that I have found that even oily parts seem to come up o.k. with the electrolytic process providing that they have undergone treatment for a day or so. Thick grease might eventually be broken down too, but I would remove it first for the reasons you have given.
In your step 2, I think your method for mixing up a Caustic Soda solution is somewhat dangerous however. It would be safer to add the flakes of Caustic Soda SLOWLY to some COLD water. This is an exothermic reaction, and so the solution will get hot as you add the flakes. By adding the flakes to the water, if it started to generate enough heat to cause some spitting of solution, any drops of solution will be much weaker in concentration, than if you add the water to all the flakes that are to be dissolved. If you use hot water you run the risk of generating steam as the addition of flakes to the water will push the temperature higher, and it may go above boiling point. If it does, most likely undissolved flakes are likely to spread around, and as they will be wet, nasty alkalai burns are likely.
I agree with most of the rest of your post and I like your idea of using each solution to neutralise each other, but I do think that you may need more than just a few amps if you are de-rusting large parts such as a lathe bed, and need it done in a day or so.

I have not tried Molasses but have used vinegar at full strength very successfully. Greg you use Bi carbonate of Soda, have you ever used Sodium Carbonate - (Washing Soda, aka Lectric Soda)? Any particular reason for using Bicarb Soda?

I sometimes either dip the part if it is small or spray it with metho to assist with the drying before it begins to rust again. I'm not sure, but I think that there must be some fine particles of reduced iron, or maybe the surface is micro etched by the rusting and de-rusting process, which causes the brown haze to appear within seconds of its removal from the process. A stiff brush like a toilet cleaning brush is useful to clean the item down during its final rinse. (Don't ask how I found out about this.)

Another tip could be that epoxy paints are quite tolerant of alkalais, and wouldn't normally misbehave if some leached out of cast iron onto the paintwork. They do go a bit chalky though if exposed to excess Ultra Violet radiation. You can use epoxy as a primer coat, and then go over it with some enamel or polyester for example, if U.V. is an issue.

Hi Stuart, What Ewan said, Cheers,
Rob.

**Stustoys** · 28th November 2012, 04:30 PM

Originally Posted by kwijibo99

If I'm not in a hurry I actually prefer to use molasis rather than electrolsys,

Hi Greg,
Has there been a thread on this?
Does this do it all or just from step 7 onwards?

Originally Posted by Ueee

Aim for the highest amps you can

Hi Ewan, Rob, But I have a 200amp supply

Whats say I aim for 12ishV at around 40amps with dishwasher powder?

Stuart

**Anorak Bob** · 28th November 2012, 05:07 PM

Originally Posted by neksmerj

I undercoated my Hercus lathe bed, inside and out, before getting to get a colour chart to match the red inside the casting.

BT, if you are listening, can you tell me a close colour, I know you have Dulux colour swatches at work.

Ken

I'm listening KJ. Cast your eyes back here -
https://www.woodworkforums.com/f65/we...ml#post1578817

Now, I've had a look at a real life sample of Colorbond Wilderness. I'm at work, not next to my ARL. The colour seems a bit murky on the sample. Call Bluescope on 1800022999 and ask them to send you a colour swatch.

Have a look here also - Colour Atlas Dulux have a colour to match the Colorbond finish.

I have a question. With all this rooting around with electrolysis, why didn't you just sand off the paint, leaving the filler, touch up the filler and repaint the bed?

BT

**neksmerj** · 28th November 2012, 05:39 PM

Hi BT, thanks for all your input, I appreciate it.

My lathe was an ex Tech school machine, and the little darlings had over painted it sky blue with what looks like a mop, there was paint everywhere.

I started off with a power wire brush, but this was too tedious so decided to try electrolysis. A new learning exercise as well.

I've got the green paint sorted, it's the red colour inside the bed casting I'm after. I could probably just pick any red, but if I can get a close colour match, I'll feel happier.

Ken

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