Restoration Tip: Electrolysis Derusting

[Bob Moseley (RIP)]

Hi guys & gals

This article may be old news to some as a restoration tip but I picked it up about 6 months ago, was initially a bit skeptical, but now am a devotee to the method. Over the last few weeks I reckon I have derusted half a Studebaker US6 6x6 using this method. I've tried the molasses method as well but find it very slow. However molasses is better for parts such as frozen hinges etc. which the electrolysis doesn't penetrate as well. Unfortunately with molasses you need warmth and therefore those living in countries that look like the inside of my freezer may not be able to use this method. A WORD OF WARNING. With the electrolysis derusting do it in a ventilated area due to the hydrogen gas released. The attached image is a Before and After shot of a Chev instrument cluster I ran through my pickle bath.

DERUSTING
(By Kevin Brown)

As all restorers know one of the most irksome and destructive tasks is derusting iron and steel fittings. There are many methods includ-ing sandblasting, bead-blasting and the time honoured molasses treatment. There is an-other method involving electrolysis. Recently I stumbled on the process in an article in an old English "Model Engineer".

To set up you will need:
(1) A good sized plastic container
(2) Water
(3) Washing soda (I get mine from Woollies)
(4) A battery charger or other source of DC power, the more grunt the better.
(5) Some scrap pieces of iron preferably marine grade stainless steel.

Method: For every gallon of water (4 ½ ltrs) mix in 1 lb (450 gms) of washing soda. The brand I use is called Lasting Earth. I started out using a baby-bath and six gallons of water but now use a plastic drum containing approx. 30 gallons. You will need to keep topping this up from time to time.

Now suspend your work in the middle of your container using welding wire or any other clean steel wire. Around it on either side but definitely NOT touching, suspend your scrap also using steel wire. Now hook up the NEGATIVE terminal of your DC power source to the steel wire attached to your work. Then hook up the POSITIVE terminal similarly to the scrap (or sacrificial plates). Switch on the power.

Pretty soon you will see heaps of tiny bubbles coming off pretty well everything in the water solution. This is hydrogen, so if you smoke, don't. The hydrogen is liberated off the sur-face of the metal and so loosens all the rust, paint or other goo adhering to your precious part.

Depending on how much grunt your DC source has (mine works at 12 volts 8-10 amps and could be a lot larger), and if you leave the system to work overnight, in the morning the rust will be a black sludge and can be easily wire brushed off your part. If still not totally clean, put it back for more treat-ment. Even the most rusted pieces will clean up to shiny grey iron again.

This process will, not damage your work in any way (unless of course you hook the work up to the positive instead of the negative lead. You can put your hands in the water even with the system running providing you don't touch a negative or positive part at the same time.

I have been using the same water (topped up) for six months or so now and don't think the washing soda has an expiry date. This stuff, by the way, is the same soda that occurs natu-rally in all the soda lakes in Africa and South America etc. where you see all the birdlife, flamingoes, ducks, storks etc. as well as crocodiles and hordes of fish including Nile perch. So it is environmentally friendly.

: Sunray - I had a bit of a problem deciding where to post this. As we are all involved with restoration would a dedicated area to this topic be appropriate.

Bob

[Bob Moseley (RIP)]

And here is "THE BATH"

[A. Hudson]

Wow,
Talk about an answer to a maidens prayer, Bob,
why didn't you leave it in just a few more minutes to take care of the dimpling on the face areas.
Not only does it remove, it replaces!!
See ya, I'm off to woolies.

Thanks
Anton

[Mike Kelly]

hi Bob ,

I have been using this method for some years with good results , it is particularly good for delicate parts that would disintegrate under sandblasting .

You can use Caustic Soda in the electrolyte solution as well as washing soda , it will remove paint as well as the rust . Caustic soda is a bit nasty and it burns skin so you have to be carefull .

It would be possible to use one of those kids plastic swimming pools and try doing a whole chassis . The great thing is , it is so cheap .

You have to keep an eye on the charger to check it isn't overheating . Also , I would not leave it un - guarded overnight in a shed .

Mike

[Pete Ashby]

Bob

My son David is using this method exclusivly on his WK60 restoration with amazing results.
The really good thing is that it's clean dust free, noise free and can work while you do somthing more useful.

It gets our vote, we have been toying with the idea of digging a shallow trench (about one foot deep) linging it with PVC sheeting lowering the frame into it, filling it up with water and washing soda and leaving it to it for a week.

Pete

[Danny Bosma]

Although I guess you know just a word off warning:

Don't apply this methode to parts with aluminium.
It will totally dissolve the aluminium parts.
Leaving you behind wondering where you'd put those darn parts you wanted to clean

Danny Bosma
The Netherlands

[Bob Moseley (RIP)]

Hi guys

Glad to be of help. Just to clarify the dimpling seen on the image, it was a very corroded housing and that was the best result. It is not my best example but I thought I'd better throw a GM picture in otherwise everyone might think I favour Fords, which I do. I wasn't aware it replaces, how does that work?

And Mike, you are right about in the shed. Mine is outside so I can leave it overnight. I wouldn't have it in a shed. I haven't heard about using caustic soda but I know what the stuff is like. I find the washing soda removes paint very well, it just peels off in strips as if you have used paint stripper.

Happy restoring - Bob

[Don Dingwall]

What exactly is washing soda????

Not a common term here in Canada--brand names?

Don

[Pete Ashby]

Don

it contains Sodium Carbonate Decahydrate. Before branded detergents were available it was sold to go in the boiling copper on wash days.

Here in the UK it can be obtained from hardware shops and most supermarkets 1kg for about £1.50 manufactured by Dri Pak

Pete

[Jon Skagfeld]

Mr Moseley.

Excuse my ignorance (in the purest sense of the word)..what is the molasses treatment with reference to metal treatment during vehicle restorations?

I've spoken to several people here in Canada who do vehicle restoring and they have no knowledge of such a procedure.

Surely one colony should share techniques with another colony, tax free! Oops, that's another story.

[Bob Moseley (RIP)]

Hi John

Molasses, as you probably know is a sugar extract syrup used for stock feed suplements etc. Its a bit like treacle. I'm not sure of the exact formula but 1 part molasses to 5-6 parts water would be ok. Its a bit like a science experiment with an enzym activity between the molasses and the rust. A by product is a thick furry scum that I think is probably penecillin. It takes a lot longer but as stated is effective on parts such as seized hinges and other areas where the electrolysis derusting doesn't penetrate. It does need some warmth and could I suppose be likened to an action similar to yeast. Its a real old timers method. The other advantages with this is that any container can be used and it doesn't give off any volatile gas.

Hope this helps.

Bob

[Snowtractor]

Tractor restorer used to fill seized engines with industrial vinegar and let sit a few months then drainout and turn over. The engine always freed up. He would flush oil passages with oil and change oil again. Then run it maybe 15 minutes and do a last oil change.
I imagine its like the molasses treatment in that you try and experiment. Maybe pickle jars and rusted bits and log the results.
Sean

[Danny Bosma]

Ah, so that's the official terminology for using coca cola for derusting.

Somehow it used to work in the past much better as it does now.
Maybe the cola has changed ??

Cheers,

Danny Bosma
The Netherlands

[Snowtractor]

Works unbelievably well on calcium build up. Use a mild solution and have a dousing pail of water to stop the reaction. I have used muriatic acid to clean carbs that were garbage , using an eyedropper to place the acid on the calcium. Be forwarned that it will dissolve the aluminum , brass the works if you let it work too long. But it cleans up a carb in a few minutes I just replace the jets and other fittings with a kit if I can't remove them beforehand.
Just remember A&W ACID TO WATER, NOT OTHER WAY ROUND.
Sean

[Richard Farrant]

Danny,
I seem to remember that Coca cola contains phosphoric acid and we used large tanks of the stuff, (acid, not cola!) in stronger solutions without doubt, to derust and clean ferrous metal parts when I worked in army workshops. You just had to remember to remove brass and alloy data plates, etc. otherwise they were gone. Carbys were also treated in a similar way but with a different chemical, it all came out like new.

There is another tip, although I have not tried it, to bring alloy parts up like new. Boil up rhubarb leaves with the parts. Heard this from a motorcycle restorer.

Richard

[Jim Rice]

I would have thought that regular low carbon steel would be better than stainless for the anode. Did you experiment with anything else?

A very helpful technique though, I wonder what amperage you would need for a frame or large body part? (e.g. jeep body)

Another method or material that I have found very useful is naval jelly. Used to be easy to get and very effective on parts that cannot be submerged (e.g. body parts for a non-frame up resto) used to be able to get it at Cdn Tire but I haven't seen it for a few years. Just brush on and let it work! A challenge to clean off at times but very effective.

[Bob Moseley (RIP)]

Jim

I was following the advice of a mate who uses this method. I believe he told me marine stainless as it has high electrical conductivity. Depending on the mass and thickness of the objects being derusted my battery charger runs between 5-10amps. A large mass such as a jeep body would probably be better in a large hot tank. I doubt whether a battery charger could handle that, or if it could it would take a long time.

Bob

[Keith Orpin]

Hi Bob,
Having spent years in the rustoration game, and being very skeptical over any rust removal process, I had a go with this technique at the weekend. I initially tried a door mirror (less glass) and then progressed to a 2 gallon can. The results are brilliant, not only does it remove rust from every possible corner, inside and out, it's also one of the best paint stripping methods I've come across !.I'm already eyeing up the plastic water butt,or maybe even the pond, (I'm sure the fish won't mind being moved)
Thanks Bob

[Hanno Spoelstra]

Originally posted by Bob Moseley
A large mass such as a jeep body would probably be better in a large hot tank.

There are firms specialising in derusting/stripping whole car bodies (often expensive and fragile sports cars) by immersion in a hot caustic soda solution. Even with the heat and more agressive caustic soda it can take days for a good result, so I doubt the DIY method described by you would work effectively. I am anxious to try it on small parts, though!

[dodgenut]

Great thread!! any more neat ideas for removing rusty stuff out there?

Am intrigued by the rhubarb leaves used to de-corrode aluminium parts, does it take a long time at the boil?

cheers

R

[Vic Eaton]

HELLO ALL
Wow my head is spinning from all those ideas i must print it all off however i claen brass with HP sause tasts good as well
vic eaton.

[Richard Farrant]

Originally posted by dodgenut

Am intrigued by the rhubarb leaves used to de-corrode aluminium parts, does it take a long time at the boil?

I guess leave the parts in until they look OK, was going to try it, but we no longer grow rhubarb, so that stopped that experiment.

Richard

[Matt]

This is very interesting! are there any side effects to de-rusting in this way? when it comes to repainting will it effect the top colour? apart from alloy are there any other parts which can't be treated in this way? I'm seriously thinking of buying a tank and giving this a go! I guess it certenly removes the problems of warping and pitting that can occur with blasting but the plastic beads do sound good.on the D15 I might use plastic beads to blast the chassis and cab but use electric method on all the smaller bits.

I'd be interested to hear more on this subject.
Matt.

[Steve Rooke]

One thing that concerns me about using a derusting tank is Hydrogen embrittlement. I do not understand it, but after doing some reading on the web I would he hesitant in using it on critical parts such as wheels or a chassis. Apparently it is a major concern in the electoplating industry. Anyone the wiser?

That said, I have no problem using it on panels or minor parts. Its the cleanest way I know of stripping paint. if I only could build a bigger enough tank to fit my cab into.

Steve

[huphuphup]

I tryed this in a 5 gallon pail with a 40 amp charger and it took about 72 hours to strip a badly rusted screw jack. I assumed that the washing soda (which I couldn't find) was the same as Arm & Hammer baking soda but now wonder if that might explain why it took so long. Anyone know if they're the same thing?

[Alex Blair (RIP)]

Originally posted by huphuphup
I tryed this in a 5 gallon pail with a 40 amp charger and it took about 72 hours to strip a badly rusted screw jack. I assumed that the washing soda (which I couldn't find) was the same as Arm & Hammer baking soda but now wonder if that might explain why it took so long. Anyone know if they're the same thing?

Same family but different...

Washing soda--sodium carbonate--is in the same family as baking soda. It has just been processed differently. It is much more caustic/alkaline, with a pH of 11, and while it doesn't give off harmful fumes, you do need to wear gloves. It is found in the laundry section of most supermarkets. Arm & Hammer is one brand; Shop and Save has a generic house brand.

Washing soda cuts grease, cleans petroleum oil, removes wax or lipstick, and neutralizes odors in the same way that baking soda does. Don’t use it on fiberglass, aluminum or waxed floors—unless you intend to remove the wax.

[Bob Moseley (RIP)]

Just to enhance Alex's answer;

Washing soda is sodium carbonate
Baking soda is sodium bicarbonate.

Washing soda is what grannie used to use in a copper before modern detergents came along.

Bob

[Dave Page]

Hi,
I tried this system last night and am very pleased with the results to the single bolt I cleaned but want to know:
1. are there any decontamination/neutralizing issues prior to priming or parkerizing and if so what is that step?
2. has anyone had success with processing batches (a handfull) of nuts and bolts held in a wire basket?
Cheers,
Dave

[Bob Moseley (RIP)]

Dave
Once I've derusted I wash the article in clean water, dry, then apply a metal conditioner. The one I use contains 24% phosphoric acid and I dilute this down to half strength. Just paint this on and let it dry for about 30 minutes. You will notice a white powdery coat has formed that you brush off. I then prime immediately with a good etch primer.
Bob

[Snowtractor]

...used to work at a rock and roll rotational plastics molding company. We made linear low density polyethylene containers in all sizes. The septic tank was rectangular 2 feet high by 6 wide by 14ft long. With the top cut off it would take a jeep frame no prob. Also the 1200 gallon ( as I recall ) was circular about 5 feet at the shoulder and 8 feet in diameter with a flat bottom. This would take a cab easy. They were about 1000 cdn. We did have the odd piece that didn't turn out or the wall thickness was too small that you could buy for peanuts.
Alternatively a wood crib of appropriate size with a vinyl liner should work. Find someone getting rid of one of those above ground pools and offer to dispose of it for them . Even new they are about 300 bucks for the the small version. Buy it and you have one large caustic tank...just keep the kids out of it.
Sean