Restoration Tip: Electrolysis Derusting

[Bob Carriere]

I used a lye solution in a 45 gallon plastic drum........

.....got some pure lye powder from the rural HomeHardware used for horses......

....used about half of a 4 litre plastic container.....solution was very caustic but it sure degreased the part like thunder.

I used a strip of stainless steel 18 inches wide hanging around the whole perimeter.......

...solution was superconductive requiring a 10 amp battery charger and two 12 volts batteries...... within the hour the axle housing hanging from the tractor bucket was derusted, degreased and both batteries were flat out and the charger was clicking on and off on overload.

Rince & dry in the hot sun... spray with mild Phosphoric acid....dry in the sun...paint with POR 15....

....serves 4 hungry people!!!!!

Watch your jeans....leaves nasty pinholes.......makes you look like a punk rocker....

Booob

[Jeff Gordon]

I have been using molasses for a number of years now and although it is i bit slooooooow, it's cheep, environmentally friendly and makes ya shed smell real good(not).
To speed up the process I pump compressed air into it every now and then.
A mate tried 100% molasses and it didn't work as well, about 25% I use.
Jeff
p.s. Wheelie bins are perfect

[Keith Webb]

As the building next door was being gutted with lots of the 12v transformers used for low voltage lighting being thrown out I thought I'd give one a try on a small scale.

So I found a 10l plastic bucket, filled it with water, added some caustic soda flakes at the ratio used for cleaning drains... then added a piece of stainless steel, which curved around the bucket, then a stick across the top with some fencing wire to hang the rusty part (in this case the small bracket which goes where the brake line meets the brake hose). It even had a rusty bolt attached.

Hooked it up with the negative to the work and pos to the stainless stee.

It fizzed away in a most satisfying manner, but after about 5 minutes I noticed a hot plastic smell and found the tranny about to ignite. So I ditched that and applied a battery charger which immediately clicked off and displayed a red fail light.

Not to be deterred I hooked up a 12v battery with charger hooked to it as well which seemed a much happier arrangement with a lot of fizzing and clouds of stuff you wouldn't want to inhale.

I ran this for a couple of hours, checking it occasionally and noting the water was becoming quite warm, along with the battery and charger which was exhibiting similar smells to the earlier transformer.

Unhooked the arrangement, washed off the part which was now quite clean of rust and paint and left the battery to recharge.

Am I correct in assuming the setup was possibly too conductive?

[Jordan Baker]

Keith

It could be that your bucket was too small. Ive read off of some other sites (can't remember where) that if the part and the anode are close they can arc out. If they touch it will happen but somtimes "close enough" is just that, close enough.


You may want to go with a bigger bucket.

[Keith Webb]

Originally posted by Jordan Baker
Keith

It could be that your bucket was too small. Ive read off of some other sites (can't remember where) that if the part and the anode are close they can arc out. If they touch it will happen but somtimes "close enough" is just that, close enough.


You may want to go with a bigger bucket.

Thanks, Jordan

There was at least 4" clearance... but a bigger bucket would also be a good idea. Ideally I'd like to have something large enough to do a door.

[jim sewell]

Kieth
What ever power source you use , you need an amp meter in the circuit ( to measure the amps ) so that you can regulate the amperage .
To regulate the amps , shift the part to be cleaned and the sacrificial further apart , draw the sacrificial item part way out of the solution , change the size of your sacrificial part ( stainless steel lasts longer )or have a weaker solution .( normal solution 1 table spoon washing soda per gallon )
Do not exceed the maximum amps available from your power source ie battery charger , transformer etc To do a door I suggest you build yourself a box and line it with heavy plastic , stand the door up and leave about 300 mm distance to your sacrificial part , use at least an 8 amp battery charger and regulate the amps at about 6 amps , remember this process works in a straight line meaning you will need to turn the door around and it may not me very effective say in a blitz door where you cannot get to the actual surface , for that one you may be better off with molassis mixed on a 5 to one ratio with water .

Have attached a pic of a GMC guard being done , I have used a sheet of corregated iron as the sacrificial piece and my power source was my ford V8 WW 2 Welder with the engine idling I could get 50 amps out of it hence the hydrogen bubbles you can see there , for insulation between the parts I used house bricks and shade cloth . WARNING . Do not pull the leads off as it is discharging as a spark may ignite the hydrogen bubbles when using high amperages .
Regards
Jim S.

[Keith Webb]

Thanks for that Jim - makes good sense. I'll incorporate an ammeter next version.

I notice you have the black to the sacrificial part... whereas others have the negative going to the work...

[Bob Carriere]

Has it seems that the highr the amps the faster it works how would one build a suitable rectifier to convert the low voltage high amperage of a stcik welder......

NOw most of us a a stick welder in the corner of the garage....t hey can put out gobs of amps...... and tyhe output is usually adjustable.....

Can someone design a diagram for a rectifier with the proper capacity to maintain say.....50 amps ... I beleive that Princess auto has surplus individual rectifiers...... the bolted kind that you would instal on a huge aluminium heat sink.... they are rated at 600 volts....

Any takers..... of course the designer would be excused of any liability...... and if worst comes to worst my widow will have a garage sale........

Bob.... Zip Zap.... Carriere

[jim sewell]

Originally posted by Keith Webb

I notice you have the black to the sacrificial part... whereas others have the negative going to the work...

Kieth , you are quite right about the polarity , I was using jumper leads to connect to the welding leads and did not take much notice of the colours . Positive ( red cross ) goes to the sacrificial part and negative ( black ) to the work .

Mig welders put out a dc current but again you would need to watch the current as it may overheat the rectifier .

Jim S.

[Lang]

Hanno mentioned commercial rust removal baths. Just be very careful!

They do a quick job with none of the sandblasting damage.

I gave one of these firms a Bantam trailer which was dipped complete into the huge vats. It came out shiny clean. They then washed it three times in other vats to remove all the corrosive residue.

I had to repaint the trailer 3 times over the next couple of months as corrosive residue kept leaching out of every seam. I spent hours with a water blaster hitting all the seams and any area where there was double plating (like around the top tubes and floor seams). The bloody stuff just kept coming. That was 5 years ago and I looked at it the other day and there is still the odd place where the paint has been stripped from the inside out.

I would suggest only single sided work be derusted in baths!

PS: Molasses works great although it will attack cast iron if left for weeks making it look sort of porous. Molasses is just pure sugar. It is the first stage of refinement - molasses, treacle, golden syrup, brown sugar, white sugar. Cows love it and farm supplies carry it but beware they often put salt in the stuff for cows.

Lang

[Mike Kelly]

For those of you who've been using the battery charger and caustic soda method of removing rust . I've been experimenting and have found a better solution that caustic soda . The local 'Warehouse' store ( chain store here in OZ, mainly in qld, nsw and vic. ) sells stuff called 'SUPREME Laundry active soaker' . It's $3 for a 1kg tub .

Start off with hot water .. it seems to aid the process a lot . The Laundry soaker is far less hazardous than caustic soda is , and is about 1/3rd of the price and it works better ! It comes in slightly different forms , I use the variant with a orange lid . ( It's made in Melbourne too )

Once you've finished derusting ,you can soak the bedsheets in it too !!!!!

Mike

[Alex Blair (RIP)]

Hi Mike ..If you look at the ingredients in your laundry soaker you will probably find that the active ingredient is Sodium Carbonate..not Sodium Bicarbonate,but sodium carbonate...That is the best grease killer and probably works on rust too..with electrolysis..
Any laundry soap with that formula,sodium carbonate will do..
Grandma was using that 100 years ago by the name of washing soda..great stuff..I use it mixed up in a spray bottle around the oven..and stove..takes off grease that has been burned on with ease..
Love the stuff and cheep..that is the kicker.

[Rob Beale]

If you mix 3 parts Washing Soda with 1 part Baking Soda you get Natron, which the ancient Egyptians used to dry out the bodies when they were being mummified.

I spent an enjoyable afternoon helping my daughter with a science fair project. We used thin strips of beef schnitzel and it was still hanging round the shed months later: no smell and no rot!

Rob

[Bob Moseley (RIP)]

Hi all - I don't know who uses caustic soda and a battery charger, but my tip, that started the Restoration Forum, was utilising washing soda. I still marvel at this process and use it exclusively for electrolysis derusting of the instrument panel parts.
Bob

[Jeff Gordon]

I have been wanting to give it a go for years and have never got around to doing it.
Does the negative or positive go to the part?
Does a higher amp charger work faster?
I was told to use washing soda and a scrap piece of stainless steel as it lasts longer.
I have a caustic soda wheelie bin for paint removal and a molases bin for rust but it is too slow.
Jeff

[Mike Kelly]

Jeff

The Negative lead goes to the rusty part ... Positive lead connects to a small piece of steel , can be stainless or galv. anything really .

I've found as little as 4 Amps works fine .. it depends on how big the part is and how close the electrodes are to each other .. Closer electrodes = higher Amps . Ideally, you want to surround the rusty part with the POS electrode ,this isn't easy to do in practice .

Watch the charger ... check it often to see it isn't overheating . If its pulling too much current , just move the Pos electrode away slightly .

After removing the part , wash it down with clean water and brush off the residue . I give the part a quick coat of that diluted phosphoric acid solution , before the air has time to recoat it with rust.

Mike

[Bob Moseley (RIP)]

Hi all - as this discussion is again the subject of another thread I thought I would bump this thread back. Perhaps a Moderator could do a combining job.
Bob

[Bob Carriere]

I used a plastic 45 gallon food product barrel and cut the top off.

Filled with water and mixed lye form the rural hardware store.....comes in 5 pounds plastic bottle...... made a fairly strong solution.

Using a piece of scraped restaurant stainless steel counter I made a huge sacrificial circular plate all around the inside of the drum...about 18 inches deep and 40 inches long..... suspended the parts to be cleaned in the solution. Small hanged from a broom handle.... the axle housings were hung form the bucket of the tractor and did only one half at a time.

A regular 12 volt 10 amp charge would almost glow red in about 5 minutes.

I reverted to using 3 large 12 volts batteries which would drain out in about 2 hours....... hydrogen bubbled real fast..... so I did all the work outside the barn in open air. Batteries were recharged overnight for a repeat.....

Lye solution had the advange of removing any oil or grease or even paint that might have been missed by the pressure washer. Solution also cleaned your hands very well as it desolves the fat in your skin...... watch your eyes for splashes...... and drops will make your jeans very religious....!!!!

Parts were rinced with the pressure washer.

Metal was ready to be sprayed with a phosphoric acid as soon as it air dried in the sun. When the phosphate coating dried I hand painted with POR 15.

It really works wonders........

Bob

[Hanno Spoelstra]

Originally Posted by Bob Moseley

Perhaps a Moderator could do a combining job.

Theads merged, sir!

H.

[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!

[Ralph Volkert]

Ooops I forgot to mention...If degreasing or paint stripping is your goal then do that. But that strength of solution is really too strong for an electrolysis solution to restore and conserve an item. It will not not only conduct current it will REALLY conduct a LOT of dangerous current unneccessarily.

[Bob Moseley (RIP)]

Morning Ralph (here at least) - Andrew Westacott's article on his site on this subject has certainly demistifyed the whole procedure for me. In fact eminating from that I will be changing some of my procedures and building a more efficient and safer de-ruster.

And as a general comment, here with Ralph, we have an expert in another field, namely science, upon whom we can draw advice from. Move over Wikipedia.

Bob

[maple_leaf_eh]

Originally Posted by Ralph Volkert

...

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.

I've read this thread end to end and find the chemistry of the simplest things fascinating. But, I read all these chemicals and acids and solutions mentioned without much discussion of disposal. Bob warned about splashing your clothes, hands and eyes. Another fellow damn near blew himself up with a hydrogen gas arc! So, what happens to the immersion bath after the part is clean? Do you guys pour it out on the ground, down a sewer or neutralize it with the opposing Ph agent? Inquiring minds want to know.

[Bob Carriere]

.....Yes Terry if splashed you wind up with very holy pants and shirt sleeves.

Solution is to splash clean water immediately thenit only bleaches the pants.

The caustic solution realy removes the grease on your hands..... along with disolving a layer of skin.

Parts, after derusting were pressure washed in the gravel driveway.... keeps the grass from invading the driveway.

45 gallon drum of caustic solution was dumped on the ground near the barn on a particular heavy rainny day....... no bald squirrels were observed in the following days...... some dandy lions took a nose dive.

We always did our work outside so hydrogen was never a problem.... the hydogen sulphide released by the Rotters was far more offensive.

We also sand blast old, I assume lead paint, CMP paint and the sand does collect extensively in front of the barn. In certain areas like Phil in NH, who is next to a water reservoir, his expended sand has to be contained as a toxic substance and disposed in a special site.

So far things have been very casual in Hammond.

The strange behaviour of the Rotters may be a symptoms of lead posioning...

BooBee

[Ralph Volkert]

Hey Terry

I didnt mean to scare anyone. In the past I have never had to dispose of more than 1-2 gallons of elecrolyte. But I have never had a carrier before either.

Bob mentioned a good point. Have a good source of clean fresh water handy in case you splash any solution on your self or your eyes!.

My solutions never have any heavy metals from using galvinised or stainless steel anodes,etc so that has never been a concern for me. I only use enough sodium hydroxide to get conductivity so yes it is caustic but probly no more and probably much less than an automatic dishwasher load uses. So I have usually disposed of it down the kitchen sink drain with lots of running water. Still it is less caustic than a drain cleaner but still works well to help keep the drain clean!

If you dumped it outside and was very strong solution you probly would be killing grass and weeds but the soil should neutralize it fairly readily.

The problem is with heavy metals. If that is in your solution and you pour it on the ground, it can get in to your garden or when it dries the dust can go airborne. I am an old Fart anyway so I am not too concerned about myself but the grand kids and nieghbour kids I worry about.

The caustic electrolye itself is not a big deal if that is all it is. But if you don't know what you are doing neutralizing it can cause other issues. It can get very hot. (hydrochloic acid or bleach mixed with it may generate chlorine gas and a wiff of that will REALLY clean out your sinuses and lungs!) So as Bob suggested, if all it is sodium hydroxide, wash soda etc judicious disposal is not a problem. (In other words don't water your wife's roses with it!)

Just remember, all you are making is a strong detergent solution. ie similar to what you use in your automatic dishwasher. Just remember if it is paint stripper bath strength you may want to dispose of it slowly because it is so strong!

When I make up a batch, I know I will be using it for some time so I just cover it up and store it in the basement or the garage for the next time. But it is also great for cleaning oil stains on the Garage floor, rags etc. So around my place it has never been around too long any way.

[Phill]

Brought this thread back to add this link from 'Shop Floor Talk'. Phil
http://www.shopfloortalk.com/forums/...ead.php?t=1695

[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