Print PDF
Favorite
Email
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).
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).
Remove these ads by
Signing UpStep 1Gather 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
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
| « Previous Step | Download PDFView All Steps | Next Step » |
A suggestion for those of you who might be using this method to remove rust from an older steel-frame bicycle. Electrolysis is the only method that I know of which can completely de-rust the inside of a bicycle's frame. It can be accomplished by putting a metal anode in the tubes, surrounded by a perforated insulator to prevent direct contact with the cathode (bike frame).
For the seat-post tube you can use something like a piece of rebar inside a piece of PVC pipe with a lot of holes drilled in the pipe. For tubes that are harder to get something into (e.g. the top tube & down tube), you'll need something more flexible. An old chunk of steel cable or the jacketing from metal coated electrical cable can work, provided you can find something that's not stainless or galvanized. Then you just need to put your flexible anode inside some old hose with a whole lot of holes cut in it and feed it into the hard-to-reach spots.
I'd also suggest not de-rusting the inside of a frame at the same time as the outside. With the anodes inside the tubes, they're very close to the cathode, and so will slow down the rust-removal from parts that are farther away from their corresponding anodes, like the outside of the frame.
I hope that this helps someone to keep a classic bike back on the road!
Turns out all that is needed is something to make the water conductive. The action of electrons leaving the (negative)workpiece on their way to the (positive)anode knocks the non-conductive rust off the workpiece. So don't fret over TSP/baking/washing-soda issue. Use any of them. In fact, plain old salt works fine: table salt, rock salt, ice-melter salt, water-softener salt. I used a cup of salt per gallon of water.
Using salt, I know for sure that hydrogen and oxygen are produced during operation. So long you don't trap these gases somehow, they will dissipate far to rapidly to be an explosion hazard, but I wouldn't tempt fate by making a spark over or in the bucket during operation. Unplug your DC power supply first, THEN disconnect your electrodes.
1. stainless steel does not conduct amps well don't use it.
2. Copper for your anode is better used and a copper pipe flatting ¾ of it with a hammer
3. the further your anode is away from your work peace is bad it takes more amps and time to work on cleaning.
4. Power 1 to 12 volts they don't matter at all amps is what matters 10 amps works the best no closer than 4 inches from what you are cleaning the farther your anode is from what you are cleaning the more amps it takes to do the job.
5. Cleaning soap phosphates use TSP you will find it in a store that sales paint it is a mild soap use
for cleaning walls in the house to paint. It will not harm you. Plus add two cups of white vinegar to 4 gallons of water in your 5 gallon buck of water mix with soap it will help to conduct the amps better. O and what I mean that TSP won't harm you I mean your hands please people don't drink it is a small joke:)
and one more thing please people stop telling people that stainless steel is toxic if they use it because its not it just wont carrier the amps. The only way to make it toxic is to weld with it over a long time or by passing volts throw it at high amps in a acid bath and I mean amps 150 amps and up.
Thank you for your time hope this helps
http://www.rickswoodshopcreations.com/Miscellaneous/Rust_Removal.htm
"It is important that any copper connected to the anode does not touch the solution. If it does, copper will oxidize to cupric ion, Cu++. The connector will be destroyed. Most of the copper ions formed should precipitate as copper carbonate or copper hydroxide, but if any of this dissolved copper reaches the cathode it will be reduced to copper metal on the iron object. Its presence will promote rapid re-rusting."
Re the stainless steel advice - there is simply too much other advice out there warning of the potential hazards of this, so I am going to maintain my statement that stainless should not be used. for example, here is one of the original electrolytic rust removal sites that was inspiration for this instructable:
http://antique-engines.com/stainless-steel-electrodes.htm
So anyway, I'm going to stick to err on the side of caution on this one and continue to caution against stainless, but am interested if there is something definitive on this. Lastly, I don't see a real benefit to stainless, its more expensive, and we are talking about a disposable anode by definition, no matter what kind of conductive material it is...
1. I only used washing soda in a 1tbsp /gal ratio. My largest tank was 7ft W X 3ft L X 3ft D. This was for the lathe bed and the Mill body.
2. My anodes are always steel plate. Plain old 1/8" mild steel. Pieces about 10inx 12 in. In the large tank I had 8 of them. In a 35gal plastic garbage can where I did most everything I used 2. I drilled a hole and bolted bailing wire (now called tie wire) to them and hung them in the bath.
3. I clean my pieces using a plastic bristle brush and some orange gojo degreasing hand cleaning stuff. Just get the grease off your part so it will conduct. This process has removed everything from unseen grease and dirt & paint, but especially rust!
4. Leave overnight.
5. remove the anodes and simply wire brush the crud off and set them aside to be used again. The anodes will corrode completely away eventually. I think it kinda looks cool the pitting and corrosion that occurs on the anode. the way I see it, the more surface area of the anode the more electrons can flow onto it and the more rust it removes.
Sorry I don't have pics of the tank ( I may somewhere) but I do have before and after pics of the machines, however in the after they are completely repainted. I've done parts hanging half in the bath then rotated over after the first part is done. Screws bolts and nuts are easy when you simply cut a long piece of wire then tie them all together with a couple wraps around them and space them about 1" apart. the results are nothing short of amazing. There is no damage to the original part.
Warning!! Get the polarity right! If not you will corrode whatever you are cleaning into something unusable really quickly.
Bare 12 gauge copper wire is excellent to secure the rebar for this project.
Please forgive my ignoramusity, I have never done rust removing with this method. My dilemma started when I acquired a very vintage/old, super crusty, rusty, from the fifties gas tank. It is crusty with rust inside and out.
My question is: Will this method work on my new to me tank? Or, Should I do the inside fist, and then do the outside?
Any and all help will be tremendously appreciated.
Thanks,
Jesse
(MrLunna13)
I would also recommend insulating the rod as it passes through the neck of the tank. If you don't, the electrolytic action will be concentrated at this area because the current will have a much shorter path to travel. You won't damage the tank, but cleaning the rest of the inside could take considerably longer. I'm not sure how nuch of an issue this would be since I have not run into this specific case before
To hold the workpiece, I used a bolt to connect an old 6" steel spring clamp to an 18" piece of galvanized wire (available at any hardware or building supply store - great stuff to keep a small roll of in the car to temporarily fix that dragging tailpipe ). A piece solid copper wire will work fine as well. (Strip a piece of house wire. At least 14ga will make it easy to work with.)
I bent the wire to make a hook to hang the workpiece where I wanted it. Just hooking it over the side of the bucket is fine. The negative battery charger clip is attached to the wire at any convenient point. I put it on the wire hook on the outside of the bucket to avoid the clip getting "crusty" from stuff that comes out of solution. The churning of the bubbles will generate some "mist" that will leave a "crust" on the clip if it's over the solution.
I used my 6volt/12volt, 6 amp, car battery charger. I use whichever voltage gives me the highest amps (without exceeding 6 amps).
This set up has worked so well, I still use it as is. I have even made a temporary setup in a 20 gallon Rubbermaid® bin to de-rust a lawn mower deck.
I found that grinding a shiny clean spot on the mower blade for the battery charger positive clip to attach, and grinding a strip of shiny clean area about an 1" x 8" on the part of the blade in solution greatly improved current flow. It might be worthwhile to grind (or sand or file) a bit of a clean spot on your workpiece where you attach the spring clip, but isn't necessarily needed.
My initial current flow with dirty, rusty blade was only half an amp at 12 volts. After creating some clean steel spots, current increased to 6 amps at 6 volts. Regrinding will be needed from time to time because the clean areas will gradually become coated with, or converted to, non-conductive material. (More current means faster de-rusting. At 6 amps, I've gotten good results in an hour or two.)
If you're using re-bar, grind some clean spots on it. A quarter to half way round is plenty. And you only need one re-bar. Multiple anodes are not really necessary.
I'm going to try an old piece of copper pipe (sanded clean of course) as the anode next time I think of it. I'm thinking maybe it wouldn't need maintenance cleaning for good current flow.
Safety is ALWAYS a consideration. Precautions are ALWAYS in order. But I have found this procedure to be as safe as charging a battery provided you use some common sense. 12 volts is safe, but the 120/220 volt mains are extremely dangerous. Secure parts to avoid accidental electrical short - jar (kick) the bucket to be sure. This method does not produce much in the way of fume volumes, but it is still wise to NOTdo this in a confined area. (I don't charge car batteries in a confined area either.) I set mine just outside the garage door and put the battery charger where it cannot start a fire in the event of overheating or failure. Since I cannot control how you use this information, YOUR SAFETY IS YOUR RESPONSIBILITY. THINK ABOUT WHAT YOU ARE DOING. DO YOUR OWN RESEARCH.
The copper pipe anode did not work well. Don't bother trying it.
My simplification was simply a "quickie" test for proof of concept. As it turns out, it works well enough for my purposes and saved me a bunch of time.
Thanks again...
btw... Fumes and odor have proven to be no issue as long as you take the same precautions as you would for painting with ready-to-use spray paint cans. The chemical reactions are just too slow to create hazardous levels of anything given good ventilation.