I’ve been saying for a long time that I’d do a post on rust removal using electrolysis. I’ve finally gotten around to doing it. In this application Electrolysis uses electricity to remove rust from an object that is submerged in a liquid that conducts electricity. It’s as simple as it sounds and is very effective. To use it you’ll need a cheap car battery charger, some wire, a plastic tub, baking soda, scrap piece of metal, and something rusty.
To provide electricity you’ll need a DC power source. The cheapest and easiest way to do this is to use a car battery charger. For a battery charger you’ll need a “dumb” one. Some of the fancier chargers today have the ability to sense shorts and automatically adjust their charging current. You don’t want these because they’re smart enough to realize they’re not being used on a battery. The “dumb” one just produces current when plugged in. Exactly what you want.
Next, you’ll need a liquid that conducts electricity well. Water is readily available but doesn’t conduct electricity well on its own. Fortunately, you can add baking soda or washing soda to it which will fix this problem. A lot of the sites online recommend washing soda and say it works better than baking soda. In my experience, I’ve found that baking soda is effective and dissolves more easily than washing soda. I usually just toss a scoop or two in the water and mix it. I’m sure there’s a perfect ratio but it works fine if you wing it.
You’ll also need some metal. One piece of metal you’ll need is a scrap piece of steel or iron. This piece is called the anode and will attract rust. The other piece of metal you’ll need is the thing you want to have the rust removed from. To find this piece, I took a trip to the flea market and found some snips for about $5 total. The ones in the top picture below were made by Compton Service and the ones in the bottom picture were made by Craftsman.
To get everything started, find a suitable plastic tub and fill it with enough water to submerge your rusty item. Mix baking soda or washing soda in the water until it has dissolved. Next, put the sacrificial anode in. Take your rusty object and remove the rust in a small spot. Then wrap a wire around the bare spot and connect the other end to the negative (black) clamp from the charger. Attach the positive (red) clamp to the anode. If needed, use a wire on the anode so your clamp isn’t in the water. Now plug the charger in. You should now see bubbles coming from the surface of your rusty object. Congrats it is working. Check out my fancy graphic below to illustrate the above instructions.
A couple details. Do not reverse the polarity. If you do, you’ll rust your object more than it already is. The bubbles are hydrogen. Some folks say to only do electrolysis outside to keep from blowing yourself up. I always run it in my garage without issue. If you hold a flame up to the surface of the water where the bubbles are you’ll get a nice pop pop pop….not that I’ve done it of course. The best anode is a graphite rod because it never gets consumed in the process but I don’t have one. If, after you turn it on, you only see bubbles on the wires, you don’t have a good connection. Wiggle the wires or make a better connection until the bubbles appear on the metal pieces. The process works fine on chromed items such as tools that have rusty spots. If the chrome is loose in spots it will come off. Even the spots around the flaking chrome will be affected because it may have already loosed at a molecular level. If you have an object that has a black oxide coating this will remove it as easily as it does rust. If you’d like a much more in depth description of the process and the science behind rust removal with electrolysis check out these two sites: Link1 and Link2.
Lets see how electrolysis works on a couple pairs of snips. Below is my fancy tub, anodes, and a couple scoops of baking soda. I use cheap pieces of rebar for my anodes.
Here are the snips in the tub all wired up with water. Later I added a jumper wire between the two halves of the snips so that both sides would get affected equally.
Here’s a closeup of the snips with the electricity flowing. You can see the hydrogen bubbles forming on the surface and rising. Their formation can knock loose rust off
The amount of time to let it run depends on how rusty the object is and how much current you have. From my experience, there is no problem by letting it run too long. Once it is finished the areas covered with rust will now be covered by a black sludge as shown below. Depending on how rusty the object was, the surface of the water may be covered by a rusty foam. The water may also turn dark brown with rust. For these snips though, there was only a light tan color with rust flakes on the bottom of the tub. The dirty water can be used over and over again.
Of course the black sludge has to be removed as well. I decided to try media blasting it to remove the sludge. The partial and final results are shown below. I realize I could have just media blasted the rusty object without using electrolysis on it but decided to try it anyways. This method results in a matte grey lightly textured surface.
The way I usually clean the black sludge off is to scrub it with a green Brillo pad and wash it with water. With this method you’re left with a smooth surface that still has black spots in it. This is more work but I prefer the results. The tools maintain an aged look.
Once the surface has had the black sludge removed they will immediately start rusting. So, be sure to use oil, wax, or use something else to protect the surface. Before I put the snips back together I sharpened them. To do this I put them in the Prentiss Vise and ran a file across the cutting edges.
Now both sets can be put back together and are ready for use. Not bad for $5, a couple of amps, and some elbow grease.