De-rusting a fuel tank - alternative method

Reading Martins âRecommissioning Commandoâ post where he asks for the best method of cleaning out his petrol tank, I thought some of you may be interested in this method. Iâm sure many of you will have come across it before but donât remember seeing anything relating to it on this forum. Iâve put it in a separate thread so it may be easier to find should anyone wish to in the future.

What you need:

- Washing Soda.

- A sacrificial anode made of steel (but not stainless).

- A 12v power source, i.e. a battery charger, transformer or similar.

- Some scrap wood, rubber or any non-conductive material to hold the anode.

- A bucket & some water.

Method:

The sacrificial anode must not come into contact with the tank but must hang down inside as much as possible, the more anode surface area in the electrolyte, the better. To suspend it inside the tank I fashion a collar of sorts out of some scrap wood or a rubber stopper with a hole through the middle. The rod should be a tight fit in the collar to keep it from sliding into the tank and bent to thread through any narrow clearance between the underside of the top of the tank and the top of any ridges/humps there may be.

Next you need to make up the electrolytic solution, Fill the bucket with enough water to fill the tank. For every gallon, add a tablespoon of the Washing Soda & Stir thoroughly. When all the soda is dissolved, fill the tank with the solution. Be sure to seal any outlets etc, a small cork is good for petrol tap holes. Fit your anode making sure it does not make contact with the tank, this is important as you will end up with a dead short if it does. Attach the POSITIVE (+) lead from your power supply to the ANODE & the negative (-) lead to the tank & turn on the power. If using a battery charger, you may need to add a battery to the set up to stop the chargers overload safety cutout kicking in. The higher the amps you can use, the quicker the process will be, but the more likely it is the charger will keep cutting out, you just have to experiment to find whatâs best for whatever device you are using. Now itâs just a case of waiting & checking back every so often, every 6-10 hours should be ok. Remove the anode each time to clean it, it should come out covered in rust, use coarse abrasive paper or a grinder to remove stubborn deposits. Itâs also not a bad idea to change the electrolyte as well, at least every second time. It will depend on how rusty the tank was as to how many sessions it will take to de-rust it completely, but just keep repeating the process until your tank is clean. Once done, wash out thoroughly & dry completely, then itâs best to do something to stop it re-rusting quickly, such as swilling some oil or similar around inside or just filling with fuel. You may prefer to use your favourite tank coating system.

This process does work but may take some time. The advantages are no nasty chemicals that will damage paintwork & it does a much better job, with much less arm ache, than rattling gravel or nuts & bolts around.

If you canât get washing soda, spread some baking soda out on a baking sheet & bake in a hot oven (180-200C) for 45mins or so & it will do the job just as well

Regards, Tim