Fuel Tank Electrolytic Rust Removal

[3Phase]

Second Stage

The electrical part of this job is complete!




Presto! The outside of the fuel filler neck has been de-rusted and so has the inside of the tank!




For the second stage: a dilute solution of phosphoric acid will finish removing and converting any rust remaining inside of the tank and it will help to prevent flash rust as the, clean, bare, metal dries. Phosporic acid can be found in many common bathroom cleaners and it doesn't take much



7.6% phosphoric acid in 16 fluid ounces



I added two 16 fluid ounce bottles with 7.6% phosphoric acid (2.43 fluid ounces or less than 1/3 cup) to 5 gallons of water. That makes a solution containing a little less than 2% phosphoric acid.

After soaking for a few hours the tank will be drained, rinsed and the phosphoric acid will be neutralized with baking soda.


Regards,

Scott

[3Phase]

Completed Tank

All done. The tank is clean and de-rusted.

Final de-rust at the fuel filler neck




Final de-rust from the left-hand fuel petcock mounting hole




Final de-rust from the right-hand fuel petcock mounting hole





Final de-rust at the fuel gauge mounting hole




This came out really nice!


Regards,

Scott

[latexeses]

Lookin' good!

[3Phase]

Lookin' good!

Thanks, Rodger!


Regards, Scott

[greatnw]

Looks great! Much better than the acid and nuts method I used.

[psycoreefer]

sorry to dig up an old thread but....

I'm trying this on my tank, the question I have for the electrolysis guru's is what does it mean when my mix stops bubbling? My tank seemed quite rusty and when I first plugged it in I got lots of bubbles and nasties coming out the filler, however after about 4 hours and 1 electrode cleaning the bubbles have stopped. Does this mean the rust is gone? Did I mess something up?

Here's my setup, using washing soda, had to have a battery in the loop to fool my charger...

[clcorbin]

Clean the electrode and make SURE it isn't shorted out inside the tank. Also, you need an "L" shaped electrode so you can get it back in the tank.

When I did my tank earlier this year, I used a piece of 1/2 x 1/2 tubing about 14" long and used a a wood clamp to hold it in place. I was using a power supply that could put about 15 amps of current down the electrode. I had to clean it (initially at any rate) about every 2 hours. It took around 20 hours to completely clean out the rust and junk from my tank.

[psycoreefer]

Sorry, I don't have a picture of the electrode but it is "L" shaped, If I make it longer it hits the "back" of the tank, probably about 14" like you mentioned. I'm sure its not shorting, when I first hooked it up it was shorted and it quickly made the electrode and wires very very hot. I'm sure its not shorted now because there is no heat. I guess when I get home I'll drain it and see what it looks like.

Is it possible for the electrolyte to "wear out"?

[gareth]

Check the voltage on that battery that you are using in parallel with the charger. I used a similar set-up when I first tried the "electrolysis trick". The reaction drained the battery very quickly and outsmarted the "smart charger"
Result:- Dead Battery, Rusty Stuff.

[latexeses]

The charger I used was an old timer. A garage sale special that has a charging range of 0-8 amps. When I first started it up it took off at nearly 7 amps and as the electrode got fouled with the rust is backed off to less than 2amps. Once I pulled the electrode and wire brushed the rust off the charger took off again at 7amps. I had to clean the wire fairly regular, every hour of so when I first started but it needed less frequent cleaning as time went on.

Check to see if you hurt your charger when it got crossed.

Rodger

[clcorbin]

Sorry, I don't have a picture of the electrode but it is "L" shaped, If I make it longer it hits the "back" of the tank, probably about 14" like you mentioned.

Cool. I couldn't tell from the picture.

Is it possible for the electrolyte to "wear out"?

Not the electrolyte, but the electrode can. It will get worn down to nothing, especially if it isn't large enough and the tank is really rusty. I've seen some pretty NASTY "stuff" being used as electrolyte and it worked perfectly fine. It just LOOKED like the sort of stuff that would consume your soul if it ever got on you!

[psycoreefer]

I'm going to drain the tank and see where I'm at, I found I mixed my electrolyte way strong, I used about a cup of soda and its supposed to be about 1/3 cup for 6 gallons. So I'll dump and re-mix. Also going to check the battery. And the charger I guess well I'm at it.

The charger was smart enough to "protect" itself but the battery in line dumped a bunch of power = hot wires. only connected that way for a moment I don't think any damage was done. It did work after that because the short was the very first time I hooked up the leads.

I wish the charger had an "amp" meter on it but its digital and only gives the option of seeing "% charge" or "voltage".

I'm on the look out for a better alternative charger but no luck so far. HF has one for 19 bucks that looks just like the old timer in the pictures but I'd rather not spend the 20 bucks.

I did remove the electrode and clean it when I noticed the lack of bubbles, it was covered in gunk and eroded, I cleaned it with a wire brush on my grinder and put it back but the bubbles didn't come back so ????

Does moving the connection point on the tank around have any effect?

[GARTHXS]

yes!!!!

You need some room for the smoke to move it looks like you have both leads on the wire?

[psycoreefer]

Yes, both positive leads are on the "electrode". I have two leads because I had to have a battery in the loop to fool the charger.

I dumped out the electrolyte I had mixed and took a look in the tank, its still rusty, so I mixed new electrolyte, using 1 Tbs washing soda for each gallon of water, just like the directions say, hooked everything back up and its working now. Only thing I can figure is that to much soda in the water was making it to easy for the current to flow? Not sure but its back to working now, the battery is good and the charger is happy, no smoke, no fire, no shorts so I'm going to let it cook for a while.....

[clcorbin]

You will be VERY happy when the process is done!