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.

[mafiamike]

Ive been using molassis for years but put it waaaaaaaaaaaay down the back cos it stinks mix 1ltr syrup to 10 ltr water

[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

[cantankrs]

Originally Posted by dodgenut

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

I tried lemons - I juiced them but a mate just popped his rusty article in a bucket with a lid, and covered the article with squashed lemons. The result was great (I'll confess I didn't try to paint my item though). The lemon juice/lemons goes off but.

Also I tried some commercial liquid (can't remember or find name at moment) meant to be enviro friendly, that you dilute and drop parts into. In 2-3 days it removed the rust and turned the articles black and after a wash and wirebrush they turned out fine, however my neighbour commented that it's not good for springs (like bonnet springs) claiming it can make the metal brittle and potentially dangerous which kind of echos an earlier post here (but not sure if for the same reason).

Re Bolts and nuts - years ago I had a box of bolts, nuts, washers I'd removed from a vehicle pickled and gold or silver zinc plated (I don't quite know the exact name for this but would like to know) by a chrome plating company. At the time it seemed a cheap cost because an employee had twitched every single item onto lengths of presumably uninsulated solid copper wire so they were seperated and could suspend them in their pickling bath, and then their anodising? and washing baths. I had to unthread/cut them off the wires but result was fantastic except for thin marks wherever the wire had been snug against the article, which wasn't a problem.

I'm intending to try the electrolyte method for bolts, nuts in a similar manner.

A backissue of The Old Machinery Magazine gave a similar lesson on Bob's method of derusting.

Alex

(Hmmmm - my apologies since I didn't realise how long this thread was and I still haven't read to the end)

[Lynn Eades]

See my post (no.39) re hydrogen embrittlement. The gold plating is commonly "gold pacifate". The ww2 plating on Dodge bolts (Excellent bolts) was cadmium plating, unfortunately, a toxic , heavy metal.

[sth65pac]

Cadmium Plating is still commonly used in the aircraft industry as a protective coating. A good electroplater will have access to this.

You will find most industrial plating places & hardchrome platers can Cad. Plate. Hardchrome is the kind you see on shock absorber shafts, hydraulic actuators and the like.

Cad plating is muuuuch cheaper than chrome plating.(Not much on a CMP chromed except the wiper arm knob ) Remember to wash you hands if you have touched cadmium plating. It is toxic, and the oxide (looks like salt) is highly toxic.

Ian

[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

[sth65pac]

Originally Posted by 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

Steve,

Whoo............... A high tech thing for Ye Maple Leaf Up!

I think that this problem (only) relates to alloys and not to regular iron/steel. Hydrogen Embrittlement occurs when stripping paint from an alloy, using some chemical strippers which are methylene chloride based (chemical paint stripper). NOTE: The alloys can include high strength steel but these would be rare in 1942, and would be like the special cross member in my Ford Capri convertible.

If embrittlement occurs, then the alloy piece in question can lose it's physical strength, and cause a catastrophic failure. Most chemical strippers have this compound in them. It affects predominantly aluminium and magnesium alloys.

It is critical in stripping alloy aircraft parts that the correct stripper is used. It was a very expensive lesson for my previous employer to learn that they had made a few million in parts worthless by stripping with a no frills stripper instead of media blasting them!!!

The damage by chemical stripping: It is sub-atomic and the parts look normal, but their strength is about ten-fold less!

As every alloy is made differently, I am personally wary of chemical stripping and my best solution to this issue is use plastic media blasting. Some blasting can be detrimental too as it can 'case harden' metals and intoduce micro-pitting which will lead to cracks and corrosion. (my personal dislike of sandblasting relates to this)

Some of you have heard of 'pickling' (in alloys) then Hydrogen Embrittlement with chemical stripper is the reverse!

It is a large subject but hopefully this will enlighten readers a bit more... It appears that the person on the WWW whom you have taken your data from does not understand what happens either.. unless a wheel contained alloy, it is impossible that it would be affected by hydrogen embrittlement. As for other parts ie Chassis and the like, they would primarily relate to alloys, not steel....lest of all your good old iron CMP chassis.

Ian

[Ralph Volkert]

There is a lot of info in this thread some good some ... not so

I used to work at a chemical plant specialising in Iron salts and worked with the chemists in the lab closely. I also worked for dept of Metallurgy at Queens University and got to pick their brains to for conservation projects!
(I also got access to the art conservation books at their Library)

Here is a link to a very good article outlining the proceedure and science of electrolysys. (http://myweb.tiscali.co.uk/andyspatch/rust.htm#achieved) The author has most of it right.

Notes!

Electrolysis does not replace lost iron on the piece you are restoring! You are are reducing Fe+III back to FE(0). You are not electroplating iron on to the surface.

The sacrificial anode is so named not because that steel is maggicaly deposited on the item being restored but because it is surrounded by hydrogen and oxygen gas. The electric potential of the power supply is what protects your item, and hastens the destruction of the sacrificical anode if it is made of a reactive material like mild steel.

Caution about using alloys and or stainless steel as sacrificial anode... The alloys such as chromium and other materials are released into the solution
These metals are extremely toxic and extreme care should be used when handling. ESPECIALLY if you are reusing the caustic solution. and allowing the waste metals to accumulate. Do not just throw this solution away in your yard or down the drain. Using just mild steel or an inert material will not create a toxic solution. It will remain just water with caustic pH.

Carbon or other inert anodes (Platinum/gold) can be used if you are REALLY worried about consuming the anodes but really, mild steel is cheap and plentifull

Restoration electrolysys should be done at a rate of approx 1mA/square inch of surface area of the material to be restored. As the author of the article mentiones, if higher rates are used you risk blasting off rust from the item and losing iron that will be lost forever and producing a very uneven and porous iron surface that will rust like a S.O.B. if exposed to the elements again! It can also form that rippling and dimpling effect of uneven iron conversion.

Oh yeah if the item you are restoring has been recovered from salt water the salts need to be leached out first before you use electrolysis. I have soaked steel items in the toilet tank for 6 months. LOL That way you dont forget to change the water and getrid of the chlorides that are leached out.

Too much current produces excessive rates of Hydrogen and oxygen gas production. A very dangerous and explosive situation. High current rates also increase the risk of accidently creating a spark!

Only enough caustic material should be added to the water to make it conductive for low current flow. As rust is converted to iron, current will increase. As hydrogen and oxygen gas are produced, the water content will decrease and it will become more caustic and you guessed it...current will increase.

Mention has also been made of rhubarb leaves and oxalic acid as a rust remover. They are basically the same thing. Note oxalic acid is very toxic. That is why your grandma always told you not to eat the rhubarb leaves!

Oxalic acid reduces rust (Fe+III) which is not water soluble to Fe+II which is water soluble. Rusted iron treated this way literally lets you wash the rust away but as the name (rust removal) suggests this removes iron from the item you are restoring.

Electrolysis, conversts rust (which is Fe2o3) back to iron Fe and if no iron has been lost through leaching or mecanical cleaning should be restored back to its original shape if done slowly and in a controlled manner.

There really is nothing magical about the process and a stable, usable restored object can be obtained.

Oh and if the link to the article is removed send me an email and I will forward it to you.

Good Luck!