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fuel tank rust

sk47

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Hello; found an online article about removing rust from inside of metal gas tanks. It is about motorcycle tanks but I suppose will work on any metal gas tank. I have two old metal five gallon gas safety cans I may try this on. One of the things i look for when shopping old cars is the condition of the fuel tank. It will not be of value to newer vehicles which have plastic tanks.


Here's How To Clean Your Rusty Fuel Tank Easily Using Electrolysis (msn.com)

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.
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Shifting_Gears

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Stuff like that is super cool to learn about. Thanks for sharing.
 

Strokerswild

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sk47

sk47

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https://www.evapo-rust.com/

I have personally used this to revive vintage motorcycle gas tanks, and the results are incredible.
Hello; I have been using evapo-rust for a little while. Last summer my brother bought a used camper. We found a pair of rusted up and locked up fishing pliers. I soaked it in some evapo-rust and it came out just fine.
Ouestion- did you dilute the stuff or use it full strength?

I have worked on some old cars and torn down some old engines. Some engines with lots of rust. I have wondered if the evapo-rust would work in a rusty cooling system or even inside rusty engine cylinders.
 

Strokerswild

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I use it full strength.

The last motorcycle tank I treated with it was an eye-opener. The bike had sat in a garage for nearly 40 years with half a tank of fuel which had turned into varnish. Once I got the varnish cleaned out (was a chore) I could see from the fill line up there was fine surface rust covering everything and I wasn't sure if getting it resolved was possible. After shaking the tank with about a pound of BBs for a while to loosen some of the scale and emptying that resulting mess, I filled the tank with Evaporust and left it sit for two days, tipping it side to side occasionally.

You can see the result in the picture. The line where the old gas was is clearly visible (too bad it wasn't completely full of old gas which would have negated the rust) and above it the surface texture is different due to pitting but is rust free. The pic was taken immediately after emptying the Evaporust.

IMG_20200114_165951.jpg
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sk47

sk47

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Hello; A couple of decades ago I had to try to fix a metal gas tank out of a 1972 Porsche 911. The owner was in a bad habit of parking it for years at a time. Park it for months or even years and then call me to get it running. After a few episodes i found rust in the tank. I think it was because the gas was only about 1/3 to 1/2 as it sat. It was inside an unheated building so water condensation had built up and settled to the bottom of the tank.
I took the tank out of the car and tried to clean it up. I rigged up some chains to suspend the tank at different angles. I put some short chains inside and the owner and i shook the heck out of it for a long time. Finally got most of the scale and surface rust loosened up.

Back then I used a product called POR15 to coat the inside of the tank. Had to make a plug to seal up the gas filler hole. We would mix up the POR15 and pour it in the tank, then move it around in as many positions as we could. That fix worked for a few years. I plumbed a see-thru filter into the fuel line where the line ran under a panel near the rack& pinion. I could remove four small bolts to check it.
I never could get the guy to stop just driving the car for a few weeks and then just parking it for months. like you say, if a vehicle is to be parked for a while fill it up with gas. I worked 500 miles from home for two years and would be away from my home for up to three months. I had a car and a truck. Whichever i left home was filled with gas and often with a fresh oil change. Never had a gas tank issue. Did have a fuel level gauge go wonky. Would show full a long time and then drop to half a tank in just a few miles.

Today i would use the evapo-rust for sure in the clean out stages. That stuff does a good job. Modern vehicles have plastic tanks, but the old iron is still around.

What do you do about ethanol in fuel with the older stuff?
 

Strokerswild

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What do you do about ethanol in fuel with the older stuff?
I won't use it whatsoever. Ethanol free premium in my old stuff, as well as yard equipment. Basically anything carbureted.
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