Electrolysis Rust Removal

[Joe Flanagan]

I've decided to try electrolysis to get the rust off the window garnish pieces of my Plymouth. The thought of sandblasting just doesn't appeal to me. So I have the first piece soaking away in a 32-gallon trash can with 4 pieces of re-bar and a water/washing soda mix. It's been in there for about three hours now and you should see the rust foaming on the surface of the water. I'll let you guys know how it goes. Takes a lot longer than sandblasting but nowhere near as messy.

[Don Coatney]

Been there, done that

 

 

 

 

 

 

[pflaming]

I've got a FEW pieces that may benefit from this process. Full instructions on what you guys did are doing would be greatly appreciated. I am guessing this would remove soot as well.

 

This morning I cleaned the inside parts of the distributor. Maybe I ought to clean it the same way. Is that possible? 

Edited May 25, 2014 by pflaming

[DJ194950]

Paul,

try a web search: Soda washing-derusting.

Lots of stories, many from antique involved people. Should be able to answer your questions. But after a few minutes reading I gathered aluminum parts are a No go for this. A 1 Gal.can of carb. cleaner  from Napa etc. works well for smaller alum parts like a dist housing, etc.

 

Doug

[Joe Flanagan]

Don, what you show is very similar to what I'm doing. I have a trash can about the same size. Pflaming, there are really good videos on YouTube that show how to do this. Very simple. I have the garnish for the rear window soaking right now. It was badly rusted from water getting through the rotten window gasket and just sitting there behind the garnish. It's all the way through in one place, which I'm going to try to repair by welding. But so much rusty foam has formed on the surface of the water, it's amazing. I'll post some pictures.

[Adrian41D-19]

what kind of electricl source do you use ?  a friend use a laptop alimentation. for small parts

[Don Coatney]

I've got a FEW pieces that may benefit from this process. Full instructions on what you guys did are doing would be greatly appreciated. I am guessing this would remove soot as well.

 

This morning I cleaned the inside parts of the distributor. Maybe I ought to clean it the same way. Is that possible? 

PP, I suggest you learn a bit about this process before you attempt electrical soot removal  Best laugh I have had in a while. Try Google or at least a forum search before asking such a question.

 

what kind of electricl source do you use ?  a friend use a laptop alimentation. for small parts

I used this battery charger.

 

[pflaming]

My apologies for the question. in short: soot is not rust and always nice to learn about new 'tools'.  At my age I don't have the time luxury to 'search' all my questions though I do a lot of 'search' research.  I do know that soot does not  come off the tools with soap and water, yet if it has penetrated the rust, to remove the rust will be to remove a lot of the soot.  

[JDaniel64]

When I am trying to remove rust or electroplate something, I use a strong acid and a little salt. Usually ice melt or water softener salt (chloride based) and hydrochloric/muratic acid. The salt provides the initial conductivity and the acid helps catalyze the removal and deposition of the unwanted surface material. Also how much baking soda did you use? The more baking soda you have, the faster the process will go and the more bubbles you will see. But get the water too conductive and you might hurt your power supply or blow a breaker 

[busycoupe]

Don't use baking soda and acid together. Baking soda is a base and the acid and baking soda will neutralize each other. As I understand the process, the purpose of the baking soda is to make an electrolyte solution to carry the electricity. Acid can also be used to create the electrolyte, but baking soda is probably safer to handle. The actual work of removing the rust is done by the electrical current.

[Merle Coggins]

When I studied this, before I did it myself, Washing Soda was preferred over Baking Soda. I found Washing Soda in the laundry detergent isle at my local grocery store. It worked well.

 

Merle

[JDaniel64]

Using baking soda with an acid would defeat the purpose of using an acid, you would still end up with an ionic solution capable of transporting the cations to the cathode though. The acid helps facilitate the decomposition of the surface of the anode which makes the process a fair amount faster. Using halide salts would not interact with the hydrochloric acid, and HCl would provide a free chlorine for transport of the ferric ions. Fe + (Cl^-)₃ => FeCl₃ + 3e^- @ the anode, FeCl₃ + 3e^- => Fe + (Cl^-)₃ @ the cathode, so the iron would be oxidized at the anode and reduced at the cathode facilitating its transport.

 

 

Interesting to note the color of Don's water in his picture, kinda green. You can tell the conditions and reactions going on, the green is from ferrous iron (Fe⁺²) probably in the form of Fe(OH)₂ which also means the pH of his water is around 8-9, and the orange precipitate on top is either FeO(OH) or most likely FeCO₃. 

Edited May 26, 2014 by JDaniel64

[BigDaddyO]

Using baking soda with an acid would defeat the purpose of using an acid, you would still end up with an ionic solution capable of transporting the cations to the cathode though. The acid helps facilitate the decomposition of the surface of the anode which makes the process a fair amount faster. Using halide salts would not interact with the hydrochloric acid, and HCl would provide a free chlorine for transport of the ferric ions. Fe + (Cl^-)₃ => FeCl₃ + 3e^- @ the anode, FeCl₃ + 3e^- => Fe + (Cl^-)₃ @ the cathode, so the iron would be oxidized at the anode and reduced at the cathode facilitating its transport.

 

 

Interesting to note the color of Don's water in his picture, kinda green. You can tell the conditions and reactions going on, the green is from ferrous iron (Fe⁺²) probably in the form of Fe(OH)₂ which also means the pH of his water is around 8-9, and the orange precipitate on top is either FeO(OH) or most likely FeCO₃. 

Uh, Yeah

That's what I was thinking.

[Joe Flanagan]

I'm using washing soda. One table spoon per gallon of water. I understand you can't use baking soda for this. For power I'm using a battery charger. The piece I'm working on right now is very heavily rusted and it's taking forever to see any results. But a little while ago, I took a wire brush to it and it didn't take much effort to get it down to bare metal. I'll let it sit a while longer, but at this rate, it would take me a month to get all my garnish pieces done. There's probably a date with the sandblaster in my future. 

[Jerry Roberts]

I'm using washing soda. One table spoon per gallon of water. I understand you can't use baking soda for this. ... 

 I have used baking soda several times for this .  it might be a slower process than the washing soda , but it did work well . 

[Joe Flanagan]

After I posted that, I read that baking soda is OK too. I have heard people say that you must only use washing soda. 

I had my battery charger set on its lowest setting while doing this. Is it OK to set it to its highest setting or do I risk tripping the breaker?

[TodFitch]

After I posted that, I read that baking soda is OK too. I have heard people say that you must only use washing soda. 

I had my battery charger set on its lowest setting while doing this. Is it OK to set it to its highest setting or do I risk tripping the breaker?

Don't know what your highest setting on your charger is. . . My 1970s vintage Sears charger has one switch, 6v or 12v. I generally use the 6v setting.

 

Current flow is, I think, an indication of how much chemical activity you have. Seems like the more sacrificial anodes you have and the better spread around the rusty part(s) the faster it goes. I suspect that the current flow likes to do "line of sight" so those areas get de-rusted first.

 

My setup is with about 8 strips of sheet metal hooked around the rim of a bucket which are all wired together. I hang the part(s) to be de-rusted in the center from a wood strip and I use a bit more washing soda than called for (I just dump some in without measuring). The whole process seems to go pretty fast in that setup. Lightly rusted stuff is clean in an hour, heavily rusted stuff is clean the next morning.

 

The nice thing is that you can forget about the stuff and not have to worry about good metal being eaten away. Years ago I lost some parts that way in a commercial de-rusting in solution which was basically an acid. Also the iron rich solution that is left over is pretty benign for disposing.

[randroid]

Gents,

 

Been a while since I've poked my nose into everyone else's business but this is one of my favorite topics.

 

1.  Be certain to get the polarity correct or you'll end up electroplating the rust to the part you want clean, which can be funny if you don't like the person who's doing it but not too productive if it's a friend.

 

2.  Washing soda can be both difficult to find and sometimes expensive.  TSP is the same stuff wearing a different shirt.

 

3.  I've used this method for removing paint, too.  Did a great job on Pigiron's cowl vent all in one swell foop.

 

4.  I found a WWII practice bomb in the middle of the Mojave Desert that got squished but didn't explode.  I used a big trash bag for the liquid and it did a grand job even in the little squished places.

 

-Randy

Edited May 27, 2014 by randroid

[Don Coatney]

This was my sacrificial lamb.

 

[Joe Flanagan]

Tod,

I have mine set up the same way as you. I have a 32 gallon trash can with four pieces of rebar attached to the perimeter and wired together. The garnish is hanging from a wooden strip in the center. My charger has settings of 2, 4, and 6 amps. There are also settings for a 6 and 12 volt battery. I have it set on 12 volts, 4 amps. The metal is now mostly black. Is this what I should be looking for? I was imagining I would get bare, clean metal, but maybe that is not so. I'm going to be painting the garnish and doing woodgraining and I want to be sure I don't get rust coming back to haunt me. 

[TodFitch]

My experience is that the black residue can be easily removed with a stiff brush. I don't know why that happens as I've had some pieces where it happened and some where it did not. And some where there was some black residue in some places but not in others.

 

It sounds like you have less sacrificial metal in your setup that I: Mine is a five gallon bucket (I've only done small parts) and I have 8 strips of scrap sheet metal each about 2" wide around the outside. With the smaller size of the bucket (less distance for the current to travel) and more electrodes I would expect my setup to work faster than yours.

[Don Coatney]

I sense an electrolysis race in the making

[Jerry Roberts]

.... The metal is now mostly black. Is this what I should be looking for? I was imagining I would get bare, clean metal, but maybe that is not so. ...   

 After the process the rust will be gone , but you will now need to wire brush the metal clean . 

[Joe Flanagan]

Hmm. Thanks Tod. That is something to think about. I wonder if I should alter my setup to be more like what you did and see what kind of difference it makes. I might add more sacrificial metal and get it closer to the piece I'm trying to clean. Also, I don't know if I mentioned this in an earlier thread but the black will not come off with a stiff wire brush. 

[JDaniel64]

The black could be carbon, since steel is a mixture of iron and carbon and only the iron would leave and travel to the cathode. Could also be iron oxide which is black and possibly an intermediary in the reaction.

 

Also, more plates/higher power supply current will not net you much in terms of speed. The water solution acts as a resistor in electrical terms, and the more washing soda/electrolyte you introduce to it, the less the resistance and the faster the cleaning. Pure water has an infinite resistance. You may set your battery charger to 25 amps but it could only draw 1 or 2 amps depending on the strength of your water solution. 

 

If you add enough washing soda to the water, to the point of saturation, that is tantamount to a short circuit and is where you start running into trouble with blown breakers and fried power supplies.  

Edited May 28, 2014 by JDaniel64