Electrolytic Rust Removal Aka Magic




Introduction: Electrolytic Rust Removal Aka Magic

This is a relatively simple, safe and cheap way to remove light or heavy rust from any ferrous object. I used this process to restore an old wood plane that I bought for $1 (it looked totally un-usable because of the rust). As opposed to grinding, heavy wire brushing and acid bath processes, this method removes none of the original steel and is not noisy or caustic.

How this works:

Several other sites do a better job of explaining the chemistry of this - but basically you set up a conductive solution and insert some sacrificial anodes. You hang your rusted tool in the solution and attach it to the negative end of the power supply. You attach the positive end to the anode and turn on the power. The current travels through the solution and in the process flakes off the rust - the flaking/softening occurs because of the reaction at the surface of the good steel that pushes the rust off.

See this site
for more info on the chemistry of it all. (now linked to a waybackmachine archive of the site - modern suggestions for this background are welcome).

Step 1: Gather Supplies

You will need:

This project cost me about $40 because I did not have access to a small battery charger. If you have a charger, then most folks with a decent shop full of crap can do it for almost nothing.

- Clean 5 gallon spackle bucket or other plastic container to meet your size needs
- 5 sections of 18” long 1/2” steel rebar ($5 at Home Depot –
buy in longer sections as needed) (DO NOT USE STAINLESS STEEL)
- 5 feet 12 awg (or so) insulated copper wire in two colors
- 5 yellow wire nuts
- several red wire nuts
- 5 feet pliable tie wire (non insulated) SEE UPDATE on Step 2 - the tie wire rusts out after about a year - you may want to use something more substantial or resistant to rusting.
- Box of washing soda NOT baking soda
- Anti-oxidant goo (IE Noalox – This is not necessary
but helps I think.
- Small battery charger or home made power supply ($20-$50 at AutoZone etc) - Its best if the charger
has a 6v option and an internal "trouble" switch that stops charging if something shorts out.
- Variety pack of alligator clips from RadioShack (unless charger comes with decent ones…)
- Outside outlet or extension cord
- GFCI protected outlet (this is a must in my opinion - working around power and water is stupid unless
you have GFCI protection
- 5 gal water
- misc clamps/small boards
- drill with 1/4 bit
- wire cutting and twisting pliars (linemans tools are best
- wire brush (better if on a grinder or dremel tool)
- anti rust spray or light oil

Step 2: Assemble Tank and Anodes

NOTE: Do not use stainless steel for the electrodes. As pointed out by a commenter on the intro page (thanks!) "The chrome in the stainless will leach out during the electrolysis and form hexavalent chromium compounds in your electrolyte. These are extremely bad for you." This is true - dont even think about using stainless steel for this project.

Assemble tank and electrodes

1) Space the rebar evenly around the bucket along the sides (running top to bottom). Mark the locations

2) Drill two small holes about 1/2 inch apart 2 down from rim for each rebar

3) Insert a 5" loop of tie wire through the holes around the rebar and out again . Lube the ends of the bar with anti oxidant compound and twist the wire tight and snip off so 1" of the wire is remaining. UPDATE: the tie wire eventually rusts out - mine in less than a year.  Consider using something more resistant to rust - suggestions welcome.  On the other hand, any time you are using electrodes, they are sacrificial - as is the wiring system that contacts the water, etc.

4) Once all rebar is in place, make 4 sections of copper wire with the ends skinned off to connect each rebar wire.

5) Wire nut each rebar to the next with a section of cooper wire (connecting the protruding tire wire (I also used Noalox on these connections). Do not connect the first and last rebar (ie: X---X---X---X---X---)

6) Add 5 tablespoons of washing soda to the bucket and fill within 2 of the rim with clean water (adding extra soda will not help&)

Step 3: Set Up Hanging Clips

Step 2:

1) Find a board (or any non-conductive object) to lay across the top of the bucket.

2) Attach a short lead of copper wire with an alligator clip attached to the water end. (I just stapled the wire to the board)

3) The clip should hang low enough to just enter the water. ( first photo below shows three clips - i was doing three parts at once..)

Step 4: Attach Charger

Don’t mess this step up – the polarity is important:

Make sure battery charger is OFF:

1) attach the positive (red +) end of the battery charger to the rebar wire

2) attach the negative (black -) end of the battery charger to the alligator clip over the water

3) I remember this by saying to myself “the rust flows off the tool towards the positive side”

Step 5: Attach Rusted Tool

1) clean a small piece of the tool where you will attach the clip - choose a place where it will also hang securely.

2) Attach alligator clip (which is attached to the negative end of the charger) and and hang the tool completely in the water. Its ok if the clip is in the water – it wont hurt it. Wiggle the clip to make sure you have a good connection.

3) Make sure the tool is attached firmly and is not touching the rebar or any part of the setup that is attached to the positive lead.

4) Areas of the tool that do not have a “line of sight” to the rebar will not be cleaned – if you have a complex part you might need to rotate it or add more rebar electrodes.

Step 6: Power It Up

1) set the battery charger to a low setting (6v – 1.5 amp works great for me)

2) Turn on the charger.

You should see tiny bubbles start to form all over the tool. As the process progresses, the rust will start to flake off and the water will become muddied with rust and goop and foam depending on how fast the bubbles are forming.

Step 7: Check Tool and Remove and Clean

Depending on the size of the tool, the amount of power used, the amount of rust, and your patience, the process will take from 1 hour to two days. The longer you leave it in the solution, the less work you will have to do to finish the clean up.

The tool will turn black and the rust changes form and flakes off.

If you leave it in long enough, you should be able to wipe the rust off with your finders and find a smooth (but pitted) surface. The nice part about this is that even after only 1/2 hour, the rust is much easier to remove with a wire brush.

NOTE: the tool will not come out of the tank ready to paint. it will still need wire brushing or final polishing with steel wool. the process leaves a gray/black layer of oxidant that you will probably want to remove prior to final rust-proofing or painting.

The photo of the saw below shows three stages: The left side was run for an hour and then brushed. The middle spot was steel brushed for the same amount of time but without the electrolysis (and rust remained) and the right side is the original rust.

Step 8: Samples

Here are a few samples:

The chisel was very rusted – normal rust removal would have required much original steel grinding to remove the deep pits that a wire brush would not have touched. Check out the stamp that was revealed after cleaning.

The entire project was started because I bought this sweet plane that was totally rusted. I only paid a few bucks, but knew that a used non-rusted one was worth quite a chunk of change. After the tank proces it took about an hour of going over it with the light wire brush wheel on the dremel to shine it up – but it would have been impossible without the electrolysis first.

Step 9: Final Rust Proofing

If you are not going to paint the tool then it will require immediate rust proofing.

I use this spray T-9 stuff that Highland Hardware sells

– but I think there are some less noxious easier to clean up products out there like Camellia oil

Step 10: FAQ

How big/small of an object can I do?

- My browsing around on the web found people doing anything from small parts in a 1/2 gallon tub to a trailer body in a swimming pool using a large welder for the power.

Does the solution "wear out"?

- No - it just gets nasty

How much power should I use?

- As little as possible to still get the job done. I think you will get better results with low power and two days of processing than high power and getting it done in an hour. The larger the object (surface area) the more power required to do it in a given amount of time. My charger is 1.5 amp 6 volt and works great for hand tools. the small stuff takes a few hours. The larger complex plane took a day and a half before i was happy with the amount of removal.

Is this dangerous?

- Only if you don’t have any common sense and don’t use a GFCI protected power source.

- Yes if you do it inside - the bubbles forming are evidently hydrogen which is flammable. Outside it does not cause any problems.

- The low voltage is pretty safe - especially if your charger has an automatic cut off "trouble" switch.

Are there any drawbacks to this system?

- Some people say that depending on the power and time involved, the steel can become brittle due to a temporary change in structure. This is cured by "baking" the tool for a few hours at 350 in the oven or letting it sit around for a few months before any hard use. see the links below for more info. I have not found this to be a problem.

These guys deserve the credit for teaching me how to do this and provide way more info on this system:




The Instructables Book Contest

Participated in the
The Instructables Book Contest

9 People Made This Project!


  • 3D Printed Student Design Challenge

    3D Printed Student Design Challenge
  • Sewing Challenge

    Sewing Challenge
  • Unusual Uses Contest

    Unusual Uses Contest



Tip 18 days ago

I have found that for small stuff the center conductor or core from dead D cell batteries works great. The process of removing them is fairly safe. Wear gloves and pry the top off. The part you want is in the center. It will be a black rod running from top to bottom.


Question 6 months ago

Hi. This a great instructable. Thanks for posting it is much appreciated. I have 2 questions and I hope that the topic was not covered elsewhere. The list of comments is quite long (500) ;-)
1)How important is the power. My battery charger has no switch and provides 12vdc/6A. Would that be too much ( I plan on using a 5gal pail)

2)They say salt make water more conductive. Any reason why choosing washing soda instead?
Thanks for your help everybody


Answer 7 weeks ago

In response to your question 2 you should avoid "table salt", i.e. sodium chloride, as an electrolyte for this application. Chloride ions are a reactive species especially with ferrous alloys. So, while it would certainly be more conductive it could be detrimental to the part you're cleaning and foul the electrodes. If you have a rusty part that you don't care about you could try it. Chloride corrosion is mostly a problem at elevated temperatures and low pH over time. However, the carbonate ions are relatively unreactive with the metal surface.


Reply 7 weeks ago

Thank you so much for the clarifications. I ended up finding washing soda and used a setup similar to yours. Worked perfectly.


Answer 4 months ago

I think you don't see salt recommended too often because a byproduct of
using salt is chlorine gas. Washing soda gives a byproduct of hydrogen
gas which - while flammable - is less dangerous.


Reply 4 months ago

Thanks for the answer. Although hard to find, I managed to get washing soda and it worked great.


Tip 3 months ago on Step 1

Thanks for sharing the instructions on removing rust. I am offering info on making washing soda if difficult to find. You can make washing soda by heating baking soda on a cookie sheet in the oven. If you heat normal baking soda at 400 degrees for 30 minutes to an hour, that process converts it to washing soda.

Coast Guard Retired
Coast Guard Retired

Question 5 months ago

Hello my fist attempt at this was in a 22 gallon tote. . I used 3/8 in black iron pipe. . I have a 12 volt 10 amp charger but could only make the needle move. My first attempt was on a rusty C clamp. . Looks brand new for something made before 1955. . My wife has a metal bird bath so I upgraded to my garden tool holder, a 55 gallon Drum. . Plastic. . Still using black iron pipe but scored both pieces with a grinder. . I'm now at about 7 amps. . My question is. . When do you know it's done. . I really can't keep pulling this thing out to check
. I started at 630.pm and will run till.morning. . Or after church. . Will it quit bubbling or will it just waste away. Thank you for your time and effort to make this how to. .


Question 1 year ago on Introduction

At what temperature will water/baking soda mixture freeze during the electrolysis process? Thank you.

Felix Pz
Felix Pz

Answer 5 months ago

Apart of the heating that provides the process, water with baking soda will lower its freezing point from zero celsius to some degrees below zero. It also depends on the concentration of the chemical in the water: the more concentration, the more degrees below zero.
You may want to look for a chart representing the solid vs liquid phases of such mixes in function of temperature (at atmospheric pressure).


Answer 9 months ago

There are too many variables to give a simple answer. Tank size, voltage, the conductivity of the solution and other things all play a part in how cold it can get before it freezes.

A solution being actively used will take longer to freeze, the voltage is keeping it warm, but it will eventually freeze.

Antifreeze can be added to a solution to reduce freezing, but that causes disposal issues.


6 months ago

I've searched and searched and can't find an acceptable answer to this question:
If the anode is painted, will it make the electrolysis slower, make it not work at all, or make no difference?

Another question: I've run across graphite welding rods on eBay. I don't know what percentage graphite they are, but has anyone tried graphite welding rods as the anode?


Felix Pz
Felix Pz

Reply 5 months ago

I've not tried this project so far. But common sense tells me that paint will make a big differece. Paint is a barrier to electricity, so the result can go from making the process slower (if there is some current thru the paint because it is in very bad condition and has micro-cracks) up to not work at all, as you mention.


Carbon arrow shafts also work for anodes and should be available at most sporting goods stores.


Tip 9 months ago

I switched my anode from steel to graphite welding gouges.

I've been using the same graphite welding gouge for the past 6 years. It has very little wear on it and it doesn't accumulate crud on it like steel does.

The water turns completely black, with no scum coating the surface. I find the pure black solution more appealing than rusty, scummy looking solution.


Question 9 months ago

How do you safely dispose of the sludge left in the bucket?


Answer 9 months ago

So long as you aren't using a stainless steel anode, the leftover sludge is safe; it can be poured down the drain or in the yard. The rusty water could leave rust marks in grass or tubs. Don't pour it into storm drains or waterways.

The leftover solution is basically just really dirty laundry water. Even laundry water shouldn't be disposed of in waterways or storm drains.

If you use a stainless steel anode, you'll created toxic waste that will poison the water supply, and must be taken to an appropriate waste disposal facility. Stainless steel can be cleaned without creating toxic waste. Stainless cathode is safe, stainless anode is poison.

If time isn't an issue, you can let the water evaporate, no matter what anode type you use.


1 year ago

As a follow up from my previous comment, I have now used this method a lot, so thanks for posting it!

Because of how the process actually works you can do it on other metals. It works brilliantly (no pun intended- or was it?) on brass and it comes out like new. I have also used it to paint strip old diecast cars for renovation. It has a couple of advantages over paint stripper- it's cheaper and it doesn't harm plastic. After leaving a day or so then a wire brush usually sloughs the enamel paint off, although I have found some more modern ones it didn't. If you can't or don't want to strip down a model and take out the plastic windows, wheels etc. you can leave them on The +ve can still be an old tin can no matter what metal is in the -ve.

What is actually happening is that the water is breaking down in to oxygen on the +ve and hydrogen on the -ve. because the oxygen react with the can, it gets rusty. because the metal doesn't react significantly with the hydrogen, it just blows off the loose rust and oxide like atomic sand blasting.

Regarding power, I just use a redundant 5v2a wall charger from an old mobile phone. It works fine one the types of things I've used it on up until now, such as diecast cars, brass vases, alloy carburettors etc. I also realised fairly early on that the wire going to the +ve can rots away quickly so I cut open a baked beak cam and put a bend in the corner of the sheet and hang that above the solution to be connect to with a crocodile clip. The other part I use cheap garden zinc plated wire and then trail it out of the solution to connect to the negative.

I remember which way by -ve removes the rust, +ve adds the rust.

Thanks again, I can't believe how much this has helped my upcycling and cleaning items!

Bolted Short
Bolted Short

Reply 1 year ago

We old guys remember vacuum tubes had an anode and a cathode. The anode (or "plate") was connected to B+.

I also think of galvanic type cathodic protection systems, which use a "sacrificial anode" made of zinc.

So, the anode is sacrificial, and it is connected to the positive terminal.


3 years ago

I have been electrolyzing found objects, Civil War artifacts, cannonballs and shells(properly disarmed), for over 40 years. I certainly recommend paying attention to the science and chemistry in this 'ible and the information sources the author cites. And, I apologize if I appear to be a know it all. Having said that, my experience has been different. I use ONLY salt. It does a great job, no problems I ever saw. You only need ONE sacrificial cathode, not several. I never heard of or experienced shadowing. I recommend using an old (American made) file. This way you can control the current going through the cathode. Just pull the file up a little if you want to slow down the process. Also, lasts MUCH longer than rebar. Salt solution takes perhaps 2-3 hours to get funky and efficient. On wrought iron the process takes off all bad metal, no wire brushing, etc. needed. Example, I cleaned a complete dug Enfield Rifle lock this way and every stamping was clearly readable. Just rinse item off and dry with a hair dryer. This article was sold perhaps 15 years later, great condition, no rerusting, no oil, wire brushing, etc. Be careful with cast iron, go slow. If you overdo it, it will get soft, almost soft enough to carve with a knife. A trickle charger with overload protection operating at low amperage is what you want. If you want less than 2 amps, just pull the file up a little. The funkier the salt solution, the better it works. But I always changed it when it got really nasty. If cleaning a two- or three-piece iron or steel item, it's sometimes better to have two or three leads going to the object. As I understand it, this is not reduction. Perhaps the author can explain if soda accomplishes reduction(conversion of corrosion back to good metal). I once read an article where immersing a non-ferrous artifact wrapped in a woven metallic blanket in an acid(I believe) visibly converted corrosion to good metal and preserved detail. I would sure like to read some comments on this. Again, please allow this intrusion into an excellent 'ible.