Electrolysis to clean out a rusty tank?

[Rams]

Here's How To Clean Your Rusty Fuel Tank Easily Using Electrolysis

https://www.msn.com/en-us/autos/motorcycles/here-s-how-to-clean-your-rusty-fuel-tank-easily-using-electrolysis/ar-AAWVeMh?ocid=msedgntp&cvid=18a3cffba7eb47b4a0b5fe1342152aa1

The key ingredient in this recipe is time to let the battery and solution work on that rust.
So, you’ve just found yourself a great project bike! The good news is, the tank isn’t a total rusted-out nightmare full of holes, dents, and shoddy patch jobs, but the bad news is, there is some rust inside. It’s a bike that’s been sitting for a while, so although you wish that wasn’t the case, you’re not exactly surprised at what you’ve found. What do you do? 

That’s exactly the type of situation that YouTube channel Brick House Builds covers with this very handy how-to video. In it, BJ of BHB walks us through the process of using electrolysis to safely remove the rust from the inside of a Honda CB750 fuel tank. 

The required parts list is simple. He uses a bike battery (a car battery would work, too), clamps, a piece of steel round bar as a sacrificial anode, a modified plastic spray paint can lid to keep the anode in position without letting it touch the metal of the tank, some hot water, and some sodium carbonate. The most important part, though, is simply time. (You'll also probably want a battery charger to keep your selected battery charged throughout the process.)

Electrolysis is effective, but you won’t start to see serious results for at least 24 hours—and maybe even longer. Above all, you need to be patient. Since the amount of rust involved will vary by individual piece, you should also be aware that you may need to use more than one round of sodium carbonate solution to get all the rust relocated safely away from your steel part.

Luckily, as BJ mentions, sodium carbonate—which is sold for swimming pools as “pH increaser”—is pretty inexpensive. Also, you’ll only need about a cup of sodium carbonate for each five-gallon bucket of hot water, if you’re following BJ’s recipe. If you already have a spare bike or car battery sitting around, as well as some clamps, probably the most expensive part of this proposition is your time. If you’re spending it doing other things (like working on other parts of your project), then that’s probably just fine.

Afterward, you’ll just need to run a bunch of water through the tank to rinse everything out. Once you’re done rinsing, if you’re not planning to immediately put some fuel in the tank, you may want to use something like fogging oil to prevent flash rusting. All in all, it’s a pretty straightforward process, and one you may find yourself using a lot if you decide that you like working on project bikes.

Haven't had to try this but, why not versus some other methods that haven't worked out so well.   At least, that's what I've been told.

Rams 

[Warlock]

Just got thru cleaning a tank. Used water and dawn to flush tank. Blew out good and added 4 gallons white vinegar or what ever your tank will hold. Let it set for 2 days. Flushed again with water and blew out. Added a pint of lacquer thinner to take the water out. Put a tank coating in it. Now I also used dry wall screws to help break up the rust by shaking the tank. One word of advice while the vinegar is setting for the two days make sure the vent line is open and can breath. It will build up pressure if left un vented. Don't ask how I know this. Guy was happy with the tank and I think I used Caswell liner.
David

[Timbo1]

I've used electrolysis on a number of old tools from a cast iron table saw to jointer all the way down to a genuine crescent wrench that was buried & dug up for who knows how long.  It's very effective and easy to do with little setup time.  I've never tried a battery, instead I use a battery charger but any dc source would work.  And my mixture has always been Arm & Hammer detergent as it's easy to get from pretty much anywhere.  

https://www.amazon.com/Arm-Hammer-Super-Washing-Soda/dp/B0029XNTEU/ref=sr_1_28?keywords=arm%2Band%2Bhammer%2Bdetergent&qid=1652240482&sr=8-28&th=1

The biggest problem I see with doing a tank is the sacrificial anode needed cant come into contact with the tank which would be the cathode.   The other thing to overcome is the small size the tank opening will allow for insertion of the anode.  The larger the surface area of the anode the better the process works as electrons (rust particles) are attracted to the anode and cover it with goo it becomes less effective so may require stopping the process and cleaning off the anode periodically.

[Rams]

I've used electrolysis on a number of old tools from a cast iron table saw to jointer all the way down to a genuine crescent wrench that was buried & dug up for who knows how long.  It's very effective and easy to do with little setup time.  I've never tried a battery, instead I use a battery charger but any dc source would work.  And my mixture has always been Arm & Hammer detergent as it's easy to get from pretty much anywhere.  

https://www.amazon.com/Arm-Hammer-Super-Washing-Soda/dp/B0029XNTEU/ref=sr_1_28?keywords=arm%2Band%2Bhammer%2Bdetergent&qid=1652240482&sr=8-28&th=1

The biggest problem I see with doing a tank is the sacrificial anode needed cant come into contact with the tank which would be the cathode.   The other thing to overcome is the small size the tank opening will allow for insertion of the anode.  The larger the surface area of the anode the better the process works as electrons (rust particles) are attracted to the anode and cover it with goo it becomes less effective so may require stopping the process and cleaning off the anode periodically.

I don't have a need to use on any tanks at this time and I surely hope I never do but, this process intrigues me.    Gonna save this and hopefully never need it. 

Rams