Electrolysis Rust Removal - Motorbike Fuel Tank




So have you just found a layer of nasty rust on the inside of your fuel tank? well we may be able to help!!
Electrolysis rust removal is easy but takes a some time.
you need;
-one 12v battery charger
-soda crystals
-strip of mild steel

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Step 1: Preparing the Tank

Firstly clean out the tank of fuel, remembering to dispose of waste fuel safely!!
Don,t worry about washing it out just shake out any loose bits if you can.
we will doing the tank in two parts, with the tank in its normal position and then upside down. both are done exactly the same way.
This instructable will show the upside down part, but right side up is the same method.
Do this in a well ventilated area, prefably outside as the process of electrolysis will produce hydrogen gas!!
Make sure the tank is stable and block any pipes coming out to prevent leaking.

Make sure the cap seals properly, if in dought use some plastic to help it

Remove the fuel level sender

Step 2:

insulate the end of your steel electrode. i am using some 12mm square bar i had lying around. only mild steel will work, so no stainless or alloy.
place the eletrode in the tank trough the hole and mark where it sits against the tank. insulate that part of the electrode, i used some rubber tubing.
it is important that the electrode does not touch the tank or it will short out the power supply.
wiggle it around and make sure that it is not touching any metal pipes inside the tank.
it should rest on the bottom on its insulator and the hole at the top.

Step 3: Filling It Up

mix 1 table spoon of the soda crystals to 1 litre of water.
fill it up to the top

Step 4:

put the electrode back in and make sure its not touching the tank.
connect the positive clip (RED +) to the electrode
connect the negative clip (BLACK -) to the tank body

make sure to get them the correct way round!!

Step 5: Switch on and Wait....................

turn on the power and wait. it will start fizzing away and bubbling. this will continue and eventually the water solution will turn really gunky as the rust is lifted of the metal. a lot will stick to the electrode.
if the tank is really bad take out the electrode every 6 hours or so and wipe it of. turning of the power first.
some solution will bubble over so make sure it can drain away.
the longer you leave it the better the result. anything from 24 hours to a week.

Step 6: Rinse and Dry

when done rinse out the tank with water and dry thouroly. put it by a heater to help it along!!
when dry shake it around to remove any residual flakes and your done.

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    21 Discussions


    2 years ago


    Did you have to treat and seal the tank afterwards, and is so what did you use?


    2 years ago

    Just trying this out on a rusty Honda Revere tank, seems to be working OK :)


    3 years ago

    i hope the power supply won't blow off, because it's being short circuited if we don't use any resistant, a light bulb or so.


    3 years ago

    I have tried the above method to clean my tank and the charger is working however when inserted in the tank it is not showing a light to indicate it is charging - any suggestions ?


    4 years ago on Step 6

    Instead of water to rinse, you should use rubbing alcohol. It evaporates at room temperature so it has a smaller chance of contaminating your gas and you can use the tank sooner than waiting for water to evaporate.


    4 years ago

    Great post. Going to try this. Should I oxy clean out all the crystallized black old gas first? Or can I go straight to this you think?


    6 years ago on Step 3

    what setting do I use 12v or 24v, 2amp 20amp 50amp??


    6 years ago on Introduction

    Soda crystals are just sodium carbonate. A cheap source for sodium carbonate is the stuff pool supply stores sell for increasing Ph.


    7 years ago on Step 6

    might help if you used an air compressor to blow out any loose particles in the tank. just remember to wear eye protection. if you thought rust in your gas tank was horrible, try it in your eyes;) lol

    Interesting. I've used electrolysis to create rust, but never to remove it. Good to know.


    7 years ago on Introduction

    Great instructable!
    do you need to do anything to the tank to keep the rust from coming back? it seems like it would be a good idea to use some gas tank sealant or do you think it's not necessary?

    5 replies

    Once the rust has been treated, just keeping fuel in the should prevent further problems. rusty tanks are normaly caused by very little fuel being left over a long period of time in the tank resulting in condensation in the top of the tank. If the tank is to be left for a long period the fill it up first!!

    I thought if you left gas in for a long time it'll go bad. Then if you run the engine with bad gas you can have a lot worse problems than rust. I'm still leaning toward using a gas tank treatment


    Reply 7 years ago on Introduction

    There are several fuel stabilizers that prolong the life of the fuel, great for winter storage and such...
    I use Stabil, and keep the tank full to avoid condensation in the tank. I can let it sit for 9 months and still use the fuel. ( I think the bottle of Stabil says good for one year.)

    better to leave fuel in and drain it out, than not too. petrol becomes thicker as it ages so you could mix it with fresh and still use it.
    thoughts vary on the usable life, however i would replace after 6 months.


    Reply 7 years ago on Introduction

    You could use an epoxy based sealer.
    There many companies out there that make this, Por-15 is one type.
    You can find them at any auto part or marine parts store.

    Good question!!
    Soda crystals is the domestic name for sodium carbonate, which is the sodium salt of carbonic acid. In our use in rust removal it serves two purposes. One as an electrolyte to help the conductivity of the water. Second is as a cleaning agent as it can remove oil and grease.
    hope this answers your question!