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TR4/4A Rust removal by Electrolysis

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Rut

Rut

Obi Wan
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I've never tried this method and after watching a few videos I'm pretty intrigued by the process. Has anyone used electrolysis to remove rust and possibly paint? If so I would love to hear about your experiences! Now this is where I go off the reservation...I've watched videos of people using relatively small containers, say 5-10 gallons, but I want to go larger. Is there any reason not to build a wooden frame with a plastic liner and derust a frame or other body parts? Tell me if I'm crazy, but if sure looks like a good way to derust the inside as well as the outside.
Thanks, Rut
 
I have used the Washing soda and battery charger to remove rust from quite a few parts. If you have no other means.....

One draw back I see with electrolysis is the amount of times you have to touch the item.

1 - soaking and wiring it in the bath
2 - Cleaning it after the bath
3 - Soaking it again if it did not get all paint rust etc....
4 - Cleaning wire brush after soaking again
5 - Rinsing then priming (could be 2 steps)

Where if you were using a good sand blast cabinet,

1 - you blast once maybe wipe down then prime.

I think the issue going larger would be the voltage required you can't just use a battery charger if you have a 20 gallon tub. Or maybe you can.... I never tried.

I now have a small cabinet sand blaster which works well too and is a toss up of which one is messier.
 
I have used the electrolysis method on a few parts, including rims. It works very well within its limitations.


  • Some paint will be removed given enough time, however, it has to be lose to begin with or the process just treats paint like an insulator.
  • You have to really, really, degrease the surfaces before putting the part in the bath. Grease and oil (like paint) will act like insulators. You need the electrolyte to be in contact with the metal.
  • You have to keep in mind that this is an electrical process like reverse plating. It works by line of sight. You will not find great results on things like water jackets in blocks unless you can wrap your steel electrode in something like a heavy porous cloth and THEN place the electrode in the cavity.
  • You have to have a certain degree of patience and you need to clean the smut off the part periodically for the process to continue.
  • Above all, you need to make sure that your steel electrode does not short out to the part you are removing the rust from.
  • Voltage is not what you worry about. A car battery charger works fine. What you will be concerned with is the current density. For your larger bath, expect to use more/higher current.
  • Also for your larger bath, plan on moving the steel electrode around periodically and if possible, use a pump to keep the fluid circulating.

The process will be fascinating at first as the streams of bubbles appear. Within a few minutes to an hour the water will turn a dark color and you won't be able to see the part. The bubbles and continual development of foam will show you the process is still working.

If you are trying to clean the inside of a block or cylinder head, another rust removal method to research is "Molasses". Like the electrolysis method, the part has to be free of grease, and oil... and it won't touch paint at all. I have not used this method but have seen the results on cylinder heads and small engine blocks. It does a good job of getting in the nooks and crannies where electrolysis has problems but you have to have a lot of patience with the process. Expect it to take weeks on heavily corroded parts.
 
Doug,
Thanks for the input and advice! Since it is line of sight I'm guessing that a long rod with rubber rings around it inserted in a frame rail could do the trick? Is cleaning off the smut just a hosing operation or do you need a wire brush? I was thinking about a child's wading pool for fenders and such and possibly a wooden frame with plastic sheeting for really large parts like a frame. If it works well on fenders and such is there any reason not to try it on a full tub? After all it's just water and salt or soda and a power supply or power supply's?
Thanks, Rut
 
I have never tried salt. The washing soda is available in Walmart stores. If you cannot find it, you can take regular baking soda and bake it in a hot oven for about half an hour to make your own. Google will tell you the exact temperature and time.

The long rod supported by rubber rings or similar will work great. What I used on one of my cleanings was some of the spiral wrap plastic wire sleeving. If you stretch it out you can leave an exposed band about as wide as the insulating band all down the length of the rod. A little electrical tape held mine in place.

I cannot think of a good thing to compare the smut to. The closest thing is the scuzz that builds up inside of cast iron sewer pipes. The particles are very fine and seem to get into your pores easily. You can rinse most of it off with a garden hose. A pressure washer would be better. For frame rails and such you could also try the type of brush used to clean out clothes dryer ducts. Only a bit of gentle brushing is needed, you will not need to wire brush the surface unless you want to. However, you will want to really clean any surfaces you plan on top coating. Any lose particles on the surface will make it hard for paint to stick firmly.

As long as the surface you want to clean is below the water level, the electrolysis will clean it. Rather than dip all of a fender or similar, you could take your time rolling different areas of a big part through the bath. As for a whole body tub? I would not try something that ambitious. However, that may just be me. If I were going to do an entire tub or frame, I would take the parts to a chemical strip and coating place. Down here I took the bonnet from our GT6 to a place called Carolina Chemstrip. They stripped the bonnet and gave it a dunk in the phosphoric acid vat to remove the rust and leave an iron phosphate surface for painting. It was relatively affordable... but that was 25 years ago.
 
Thanks again for the info! I'm a member on the HAMB, but didn't think about looking there...a really good resource. We are inching our way toward building a house with a shop and it will be a year before its ready, but this looks like something I can do in our current back yard.
Thanks, Rut
 
I have used electrolysis to clean parts for some time. It is a slow process, and in most cases it can do a good job. I find that the longer the current is applied the more the cathodes (-) get coated and it slows the process down.
Last year I pulled a tank from a TR6 that had rust inside. I filled the tank with washing soda and used an old tire iron as the anode. It was like reverse plating since all the rust particles were attracted to the anode.

Here's the setup I used (the fuel tank is filled with the washing soda)
Fuel Tank.jpg


Here's what a pic of all the rust that the anode collected. I would clean it off every so often and reinsert it back into the tank to continue collecting rust.
P1010799.jpg
 
I have been using the washing soda/electrolysis method to clean cast iron cookware. After working for a while the cookware comes out of the bath clean as it can be, all the cooked on grease has been removed from the surface.

The power supply is being used as a current source not a voltage source. The rate of cleaning/de-rusting will depend upon the surface area of the part and the current capability of the power supply. A couple of "D" cells will take the rust off of a body tub but will take a very long time and many batteries to do so.

As mentioned earlier the current travels most efficiently in a line of sight so the electrode and part needs to be moved with relation to each other. This can be done every 1/2 hour or so.

Cavities in the part will not be cleaned unless the electrode can be placed into the cavity. This is a physics related problem based on how Faraday cages work.

Also this process works with iron parts. Not aluminum, pot metal, brass, or plastic. Mixing of other metals with the iron part being de-rusted will cause the other metals to dissolve. Also not to be used on plated parts such as bumpers. You would have a nice rust free iron bumper without the copper, nickel, or chrome layers.
 
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