Picture of 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

Step 1: Preparing the tank

Picture of 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
jchavis26 months ago

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.

mikemehak10 months 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?
trucker1011 year ago
what setting do I use 12v or 24v, 2amp 20amp 50amp??
hdscarbro2 years ago
Soda crystals are just sodium carbonate. A cheap source for sodium carbonate is the stuff pool supply stores sell for increasing Ph.
bahaminb2 years ago
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.
dimtick3 years ago
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?
professor sparky (author)  dimtick3 years ago
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
rainger dimtick3 years ago
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.)
professor sparky (author)  dimtick3 years ago
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.
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.
kricketone3 years ago
What is soda crystals?
professor sparky (author)  kricketone3 years ago
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!
mikeasaurus3 years ago
great writeup, thanks for sharing the info!
professor sparky (author)  mikeasaurus3 years ago
Thanks, its my first of hopefully many!!
You should enter this into the Chemical Reactions Challenge!