The Stovebolt Site Forums The Shop Area Paint and Body Shop electrolytic rust removal!

Fellow 'bolter Cletis mentioned in another thread about using electrolytic rust removal so I made a simple set up and just hooked it up. There is a thread in the Tech Tips section here also. I was out of tsp, so I just used baking soda and water, and a piece of stainless strap that goes around the inside of a five gallon bucket. You have to keep the battery charger clips out of the solution, and make sure you don't have a direct short. Polarity is negative to the rusty relic and positive to the stainless electrode. I'm trying to remove the rust from an old hub right now with a gallon of hot water and a couple tablespoons of tsp. The charger is humming, and tiny bubbles have formed on both the electrode and the rusty hub.
If anyone else has done this let us know how it worked and any cautions. Up here in rust country this could be a real useful tool ;if it works out.
One caution I read is to make sure the polarity is correct. Otherwise the rusty object could erode away...

Splashoil,

I too was intregued by this set-up so I gave it a try. I used a sprocket from an old come-along and put the positive cable from the charger. I couldn't find Arm & Hammer washing powder so I used Ingles brand baking soda (one tablespoon per gal. of water) What I was taking rust off was the coin mechanizm from an old Coke machine and it was really rusty. After six hours with the charger - used a ten amp but the needle only moved about a quarter of an amp on the gauge the water bubbled about like the home brew that I used to make years ago and the water turned about the same color as the home brew that I used to make. But, the rusty parts turned black which is a sigh that the rust is gone. Some of the parts that were rusted solid even started moving. I really think the process really works well.

Truck Tinker

I don't know why I never tried this before. Today my experiment resulted in a nice clean AD front hub that had really looked hopeless. This was cleaned while I mowed the lawn and loafed! There is no real costly stuff needed to do this. I'd say it really works great!
I would like to try it on some rusted fenders or running boards. Just need to set it up right. Could make a plywood and scrap lumber box and line it with visqueen. No heat buildup and potential for warping. It's a little slow but steady. It's like the carb cooker, just a passive activity. Using tsp instead of soda, it might even remove paint, don't know for sure.

That sounds really neat, splashoil. Would you be interested in taking pictures and writing a tech tip?

This will be very interesting. With that kind of surface area, I would think that will need to provide more than 4 amps to achieve timely results.

There is already a tech tip on this. I guess the "washing soda" had me bamboozled it's just common baking soda. The stainless electrode was just some scrap I kept tripping over but was unwilling to toss. I was being conservative using the smallest charger I had 1.5 amps since I had never tried it. It's so dam easy, you will be amazed. You don't have to sit there and watch it, just hook up come back in 2-3 hours. I usually pull relic then and scrape surface rust off, rinse and go a little longer if it needs it.
The only thing is when you are done, rinse, clean and wipe dry. Keep it dry. Then before painting, I think you need to wash wipe down with something like zero-rust Prep step which would give you the best PH for the paint to adhere to. More amps may make this go faster, I don't know. You can probably set this up in about ten minutes if you have the stuff. You may be able to use copper pipe for the electrode too. Once I'm done with the hubs (cleaning for disc brakes) I will move on to stuff like battery box covers, hold downs, small stuff. When I get a bigger setup I will use this on wheel rims and brake backing plates etc.. Once you try this you will ask why you never did!

Thanks for posting your experiences, Splash.

Just a couple of points. First, washing soda is not the same a baking soda. Washing soda is sodium carbonate (Na2CO3) and baking soda is sodium bicarbonate (NaHCO3). Washing soda is better than baking soda since it is more soluble and produces a more basic solution (which is desired).

Second, many of the web sites that discuss this technique strongly recommend AGAINST using stainless steel for the anode. The reason for this is that you will be producing very poisonous chromates in your electrolyte. Here is a brief description of what happens and the potential hazards: Stainless Steel Electrodes

Also, at least one of the sites I visited stated that copper should never be used for the anode.

Here's a few other sites that discuss the technique. The first one is excellent IMHO.

Rust Removal Using Electrolysis

Rust Removal using Electrolysis

Electrolysis, the science behind it

OK, I've been doing some more searching. How about using this technique to de-rust an entire frame? Trailer Electrolysis

Thanks Jeff! I'm going out now to shut it down. We have a hazardous waste place where I can take the residue. Better late than never. Hope everyone reads this.

I think you can swap polarities with a scrap piece of iron to make the chrome in the solution go back to the stainless. I'm not too good with electrochemistry though.

Can Soda ash be used instead of washing soda?
I think it is the same and can get it at pool stores.

Sodium Carbonate is available in two distinct forms and to differentiate one is known as Soda Ash and the other as Washing Soda. The first is anhydrous (contains no combined water), it normally looks like a white granular powder and has been dried out at quite a high temperature. The other has 10 molecules of water combined with each molecule of sodium carbonate, and is made from a solution in water, it is in the form of large glassy crystals. The main difference is that it needs about 5 times the weight of the latter to give the same amount of sodium in the solution. This form is the type of sodium carbonate which is normally bought in the shops - as washing soda. Professionally it is worth (ie cheaper for the amount of the working chemical purchased) getting the anhydrous form (Soda Ash), but for the occasional use then washing soda is more easily obtained.

Read the material -- admittedly only a little deeper than skimming. Concern: Hydrogen embrittlement. If electrolysis is used on suspension parts -- will lower current reduce this problem or is it a direct result of the amount of rust removed. Also, will heating at 150C correct this problem totally, or should one just not use this process on suspension parts???

My suggestion: Set this up and try it out. Pick out a rusty relic for the experiment, use baking soda if you don't have the washing soda, you don't really need a lot of current IMO at least for something small. Good coverage is line of sight, or something that goes all the way around is a good idea. Once you start using this, you'll wonder why you had never tried it. It sounds like the embritlement issue is only a temporary state, maybe someone can add some more info on that. But there are a hell of a lot of items where that is not an issue.