How to clean the inside of a metal fuel tank?

[frank mccune]

     Hello All:

      Is there some way that I can clean the inside of a metal tank?  I do not want to disassemble the tank, so I would like use a “solvent” to remove that nastiness that inhabit the inside of these tanks.

     Tia,

     Frank McCunelg

[Dane Martin]

 following this. My friend gave me an El Diablo with a Veco 19. Flys awesome,  but schmutz keeps coming from the tank, blocking the fuel flow.

[Dan McEntee]

     Hello All:

      Is there some way that I can clean the inside of a metal tank?  I do not want to disassemble the tank, so I would like use a “solvent” to remove that nastiness that inhabit the inside of these tanks.

     Tia,

     Frank McCunelg

   Fill it full of white vinegar and then put it in a ultrasonic cleaner after you cap off all the tubes.  I use plain white vinegar from the grocery store to clean the rust out of metal gas tanks for vintage dirt bikes. Works wei. Ther is also a product called Evaporust that is available at some auto parts stores and hardware stores.It's about 15 bucks a quart. I've used it and this that white vinegar works just as well, but not as fast, and is only 3 bucks a gallon or so. The wife may have a gallon stashed to make house hold cleaner from. Borrow a few ounces from her!
   Type at you later,
  Dan McEntee

  PS:    You can get a decent ultrasonic cleaner from Harbor Freight.

[FLOYD CARTER]

When I find rust inside a tank, I toss it.  Rust will never go away.  Keeps coming back.

[Istvan Travnik]

Rust is not the worst enemy in the fuel tank.
One colleauge of us discovered that some conserve cans made of the same material (double side tinned 0.2 mm soft steel).
He found whatsoever lacquer coat over tin, on the soldering stripes scrached off, and put together the tank. The lacquered surface remained INSIDE!!!
The result was not surprizing: by the next two years he was not able to complete a normal flight, the slowly released bits of lacquer resulted constant  engine adjustment troubles.
When we realized what happened, gave him a normal tank, asked for this bastard, and step on immediately, just like Fred Astaire and Ginger Rogers...

[Dan McEntee]

When I find rust inside a tank, I toss it.  Rust will never go away.  Keeps coming back.

     If you get it clean enough and use it, it can work for quite a while especially if you have some castor in the fuel. Like I mentioned, I use white vinegar to clean out the rust in metal motorcycle gas tanks, and once clean, I slosh around some premix and have never had one start growing rust again, and here also it helps to keep fresh gas in t also.
  If the tanks are built into the model, you don't have much choice. I own Mike Gretz's Fierce Arrow, and got a few flight son it before rust flakes started to come out of the tank. The tank is built in, so I can'r remove it. I filled it up with white vinegar and let it sit a day or two. Flush out with some old fuel, fill with some frsh Fox .35 fuel and put a ground run or two on it. Then check the fuel filter. running the engine creates the sonic cleaner effect. After several treatments like this, the filter started to stay clean. I filled the tank and capped it off until the next time I get a chance to fly it. When I'm not flying it, I plan to store it with some lantern fuel or something to keep moisture out and cap it off. Sometimes it's what you gotta do if you want to fly the model.
  Type at you later,
   Dan McEntee

[Brett Buck]

     Hello All:

      Is there some way that I can clean the inside of a metal tank?  I do not want to disassemble the tank, so I would like use a “solvent” to remove that nastiness that inhabit the inside of these tanks.

     Tia,

     Frank McCunelg

    What do you think it inside it? Rust?  Old castor oil?

    Rust, I would you evapo-rust, which unlike acid-based products, will not cause further corrosion. Old castor oil, I would use lacquer thinner.

   In either case, fill it up and leave it, days if possible, shake it occasionally.

     I presume that this is is in an airplane, so, if laquer thinner, be careful about getting it on the paint. If there is any question about a removable tank, just make another one, it's an hour or two, and much better than trying to clean out anything.

    Brett

[M Spencer]

hydrocloric acid may be a bit harsh , but it sure would clean it . Then the boil in baking soda to kinda get a watever it is film on it . After flushing ( with petrol , maybe . ).

[frank mccune]

      Hello All:

      I will bet that the deposits inside of the tank are not rust but dried castor oil.  When I scraped the inside of the tank, I got an amber colored pile of flakes.

      I think that the best option is a NEW tank.  Life is too short to muck about with small problems!


     Be well,

    Frank McCune
     

[ericrule]

Hi Frank;

I agree with you about the castor oil residue. Most folks manufacture fuel tanks using two sided zinc coated steel (that's what I used at RSM) so rust I snot likely to be the problem. What normally happens is that a model is stored after flying, it sits around with a bit of fuel residue still inside. That residue has castor oil in it and when it dries what is left is very similar to a coat of varnish. When new fuel is put into the tank it dissolves some of the hard coat and that gets into the new fuel, goes up the intake tube and clogs the spray bar.

I would suggest two things:
1) fill the tank with solvent, cap the tubes and let things soak for a few days. Shake it a fair bit and blow it dry. Flush the tank a couple of times with denatured alcohol and let things dry overnight. Try new fuel in the tank and see if it has cleaned out the residue.
2) If you do not plan to fly the model for a while. Fill the tank full and cap the tubes while the model is going to sit unused. I used to do this when I lived in Canada and had the models sitting in the basement over the winter. The full tank would not gas off the fuel over the winter due to the capped tubes. Since no fuel dried out there was no residue. All I had to do in the spring was blow out the tank, fill it with new fuel and go flying.

Hope this helps you
Eric Rule

[FLOYD CARTER]

Once any interior plating is damaged or worn, you have unprotected steel.

Ignoring castor oil for a moment, consider alcohol-based fuel, with castor or not.

Alcohol attracts water (it's everywhere in the atmosphere). So some always gets in your tank.

The Oxygen in Water + steel = Ferric Oxide (rust)

Clean it if you want.  Rust will come back.

[PaulGibeault]

Just as an addendum:  Certain TOP speed fliers fill their metal tanks with Mobil Jet II turbine oil to inhibit corrosion inside the tank.  YES, it's an extra step to flush it out before flying, but speed fliers don't seem to mind & any residual oil only makes them go faster...For what it's worth.  They inhibit their engines after flying with the same oil as well. Horses for courses... 
Cheers,
Paul

[Dan McEntee]

Just as an addendum:  Certain TOP speed fliers fill their metal tanks with Mobil Jet II turbine oil to inhibit corrosion inside the tank.  YES, it's an extra step to flush it out before flying, but speed fliers don't seem to mind & any residual oil only makes them go faster...For what it's worth.  They inhibit their engines after flying with the same oil as well. Horses for courses... 
Cheers,
Paul

    I believe that once you get it to a satisfactory condition, you could fill the tank with anything to displace the fuel and air inside then cap it off. I suggest Coleman lantern and strove fuel because it is relatively cheap, does not contain anything caustic, will absorb any left over fuel, and when it's time to flush out and use again, any remaining in the tank will combine with the glow fuel and pass harmlessly through the system. I know that rust could reform if you give it the correct conditions for that to happen, but if the correct steps are taken to prevent it, it can be prevented also. You just have to take those steps and precautions.
   Type at you later,
    Dan McEntee

[mccoy40]

All,

I was wondering if the anti-freeze in the crock pot trick might work for the tanks as well.

My only concern is that if the anti-freeze will get hot enough to undue the soldering on the tank.

Any Thoughts?  The crock pot anti freeze seems to work on my fox 35's pretty well

 

[Dan McEntee]

   No, the crock pot would not get anywhere near hot enough to melt solder. I honestly had not thought about that. if there was rust inside ( and there usually isn't a lot in all the tanks I have been into) the rust inhibitors in the antifreeze may soften it up enough to flush out. it would for sure clean out any old sludge and castor gunk. Like anything else, it is worth a try. If you try it, report back on what you experienced.
   Type at you later,
    Dan McEntee