Fuel tank rust

[trent]

What are some ways to clean rust from Inside fuel tanks.

Long time ago a farmer told me about mixing some kind of acid with water and dumping into tank and move/shake it all around and repeat if necessary, and coating inside with liquid wd40 then draining and put to use.

I bought a bike with the coating stuff on the inside of fuel tank once, the coating started pealing away, tank was in horrible shape,probably why it didnt work ? and had to get another tank.

[Nessism]

Some ways...

Evaporust
Phosphoric acid (most commonly used in industry. Check Kleen Strip Etch and Prep, and/or, concrete cleaner)
Muriatic acid (nasty $hit. Not recommended unless you are in a hurry and know what you are doing)
Oxalic acid (commonly found in deck cleaner)
Acetic acid (vinegar)

Remove petcock, fuel sending unit, fuel cap, and fashion plugs. Allow the tank to vent, otherwise it may build pressure and pooch out.

Also, realize, that you can't properly derust a tank if there is varnish inside. Removing the varnish is always first step in the process.

[unfocused]

Muratic acid is what we used when I worked in the industry. Brother still does this and then lines them with Red-Kote. Etching the fuel tank with some kind of acidic chemical is always recommended. If you just want it cleaner, throw some nuts and bolts inside and shake it until you realize there is an easier way

[slayer61]

I used vinegar on my wife's bike and it worked great.
1). Seal tank, fill all the holes, petcock port etc.
2). Fill to the top with white vinegar.
3). Leave fuel cap unlatched to allow venting to take place
4). Leave sit for 24 hours. Agitate if desired
5). Pour out vinegar. Salvage for other projects

20220427_173905.jpg

[slayer61]

Look at the results! Oh. I forgot to mention, I also made up a baking soda & water solution to neutralize the tank, rinsed thoroughly and put the shop vac on blow to dry the tank. Before rust starts to flash again, I used some 2 stroke gas but you could use diesel or kerosene to put a light coating back on the tank interior

20220427_164722.jpg

[Grimly]

I'd be leary of muriatic (hydrochloric) acid, as the chlorine ions left behind are notorious for starting off corrosion again, even when washed well or attempted to be neutralised.
Acetic or phosphoric acids don't leave the same legacy behind them.

[Nessism]

I'd be leary of muriatic (hydrochloric) acid, as the chlorine ions left behind are notorious for starting off corrosion again, even when washed well or attempted to be neutralised.
Acetic or phosphoric acids don't leave the same legacy behind them.

I'm a big fan of phosphoric acid. It's commonly used in paint prep products because it removes rust, doesn't need to be neutralized, and it leaves a passive film to retard flash rust.

[Eli69]

Lots of good suggestions here. Which one will you be trying on your tank trent? And which bike is this for?

[trent]

Lots of good suggestions here. Which one will you be trying on your tank trent? And which bike is this for?

I did what farmer suggested, local farm store had some Muratic acid, stuff was cheap, figured It would be more.

Rinsed out with plenty of water and took some wd 40 and sloshed it around, drained, did that several times .

Did this to 81 gs1100 tank several years ago, and it worked fine...had no issues.

This time I'm gonna try it on friends old tractor that came with some property he bought...it runs fine, but the cheap inline fuel filter gets rust in it , enough it will clog up the filter and we think the float bowls run out of fuel and it stop running.....

if we wait for ten fifteen minutes fuel seeps through the rust/filter fills float bowl and will run for a while, until it runs out of fuel.

We put on new filter, see thru kind, and it will run for quite a while we can see rust accumulate in filter.

But I figured there might be other/ better alternatives to cleaning this tank I could suggest he try, not sure what he'll do., he want to coat it?

Looking into the tank, it doesn't look to bad, but we can only see in a little ways?

[slayer61]

I was watching one of my Saturday morning (the Mrs. isn't up yet ) car shows. They put 4 or 5 filters in series. When the first got clogged, they removed it & let the 2nd become contaminated.... seemed like a novel idea.

[Nessism]

I was watching one of my Saturday morning (the Mrs. isn't up yet ) car shows. They put 4 or 5 filters in series. When the first got clogged, they removed it & let the 2nd become contaminated.... seemed like a novel idea.

Novel as in dumb? How about fixing the car properly? What a concept!