Electrolysis Rust Removal Fuel Tank Repair

Removing rust from parts seems to be something I need to do way too often. I came across this electrolysis rust removal method while researching the best way to remove rust from a motorcycle gas tank. I didn't want to purchase a gas tank sealer kit and found out as long as your tank isn't rusted through, there is no need to seal it. Electrolysis rust removal is really easy to do and kind of fun as well. Before I get into this rust removal techniqe, there is one very important thing you need to know.
DO NOT USE STAINLESS STEEL FOR ANY PART OF THIS PROCESS! Using stainless steel as your sacrificial electrode will create the "Erin Brockovich" poison. Mkay, nuff said there. The other rule of thumb is in regards to the polarity. Your PART is ALWAYS NEGATIVE and the sacrifical steel is always positive. Get the polarity backwards and your part will quickly rust and deteriorate! By the way, the electrolysis rust removal process can be used on almost any metal part, it doesn't have to be a gas tank. You can suspend your part in the soda water instead of filling your part with it. For example you could line a bucket with tin and suspend you're rusty metal part in the bucket (remember no matter how you do it, you're part is always connected to the negative cable from the battery charger). The rust removal works on kind of a "line of sight" principle, so if you're sacrificial electrode isn't in the line of sight of a certain area of your part, the rust likely won't be removed from that area. Also the more surface area on the electrode the better, but as you will see in my test below, a smaller electrode will work, it's just not optimal. Please remember, the sacrificial electrode can't be touching you're part, only the soda water.

Exhibit A, the rusty gas tank from my old Harley Davidson Sportster. As you can see the metal inside the tank is rusted and dirty looking. This is typical of a gas tank that has sat for a while without fuel in it. I removed the petcock from the rusty fuel tank and plugged the hole with a rubber stopper. gas tank rust

I used this ibolt for my electrode since it was handy in the garage. Most bolts like this have a zinc coating, I sanded the zinc off the round end a bit with a scotch brite pad. When I do this again, I will use a longer piece of soft metal as the electrode, bend it such so it goes down inside along the side of the gas tank (without touching the tank), and then stop an switch it so to do each side of the tank for a while (remember line of sight). electrolysis electrode

I found this black plastic thing in the garage, it already had a hole in it and looked like it would work perfectly to hold the ibolt in the tank so I decided to use it. You can pretty much use anything that doesn't conduct electricity for this. We are removing rust from a gas tank, it doesn't have to be pretty :-) rust remover electrode

I screwed a nut on the back of the ibolt just far enough so the ibolt will hang in the tank without touching the inside of the tank. no gas tank sealer

After filling the gas tank with warm water, I added approximately 1/4 cup of LAUNDRY soda. Just to recap, laundry soda is different from baking soda. You can find laundry soda at most grocery stores. More isn't better here, about a 1/4 cup will do just fine. Here I am lowering the sacrifical electrode into the soda water mixture. We're almost ready to start removing rust! no fuel tank sealer

Remember POSITIVE on the electrode, NEGATIVE on you're part. Connect the terminals before you plug in the battery charger. I put the black tape on just to hold it in place. In no way do you want to seal the gas tank. do this in a well ventilated area and let the gasses escape out the top. gas tank repair

With the battery charger plugged in and set at 6 Amps, the rust removal process is drawing about 2 Amps here. I left it on for about 50 minutes on this first run. I would have left it longer but I had to go do something else and didn't want to leave it sit there unattended. fuel tank repair

Look at the soup in the gas tank after just 50 minutes! I dumped out the muck in the tank and rinsed it out really good with water. Next I used a heat gun to blow inside the tank until it was dry. I finished by spraying WD40 all over inside the tank. After just a 50 minute run with this small electrode, the tank was quite a bit cleaner on the inside. Success! motorcycle gas tank repair