Fuel tank rust removal

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Fuel tank rust removal


Post by mbskeam » Mon May 01, 2006 1:53 pm

Author: mbskeam

any ideas that you guys have to get rust out of a fuel tank.
the paint job is good, so no acids. does vinegar work?
any ideas?


Post by pegtooth

Mike, I've been using the 50/50 lemon and vinegar mix with good results. Pretty sure it came by way of Billy , so I'll guess he'll know all the pros/cons.

Post by cotten

Vinegar and lemon juice are both acids, yet neither will hurt paint.
Citric is my favorite, but expensive.
If you smear petrolatum over all important paint for protection, muriatic is very fast and effective, but still only attacks the surface corrosion. Any 'scale' must always be removed first by mechanical means, like shaking with aquarium gravel or old roller bearings.

Good luck,


Post by Panhead

Put a handful of small pebbles in the tank and drive around for some days. That will loosen the rust without damaging the tank itself.

Post by billy


So what R U using for Rust removal ??? & how's it working ???

Post by mbskeam

well I think that I will try this.......

http://www.jalopyjournal.com/forum/show ... ectrolysis

I will just fill the tanks up, put the rebar into the neck, hook it up and let it rip. I will try and get pics of this......
but now I am going to try and get the kream crap out with acetone, and not F'up my paint.
I figure if I put the tank level at the fill neck and use a long funnel away from the tank I can get the acetone right up to the neck . it only takes about 15-20 min to break it down into small chunks.then I will open a petcock that have rigged up at the bott. outlets
I did some test on the kream that I pulled out in big chunks.
straight acetone seams to work best.tryed a 50/50 mix with gas and it will break it down but not all the way, and a 50/50 mix with lacquer thinner.
don't try and rinse the tank out with water when done as it will turn the broke down kream into a sticky mess, I will just use gas to rinse the tank out then dump it and maybe anther acetone bath and repeat the the dump and rinse until I think its all gone........


update... straight lacquer thinner works, but it takes about 4hrs, and will be safer to the paint I have. http://www.sikkens.net/

Post by red55fl

Excellent links! Good information to have! I bookmarked them all! :)
I have heard & read about this process before, but never had occasion to try it.
Let us know how it comes out.


Post by billy


I'm somewhat familiar w/these...too
I sure wouldn't be doing any of those processes inside & certainly NOT close enough to breath any fumes.
Bad stuff..
Whatever you do do NOT us stainless for a metal rod, in this mix. Combo is Extremely Toxic !!

Just my 2 cents, but use caution..

Post by mbskeam

ya, I will be doing this outside, and got me a piece of re-bar yesterday, got the soda wash today, so when I get some more lacquer thinner on Mon. I will strip the tank of the kream then will get to the rust removal.

KREAM should be made illegal


Post by billy

KREAM should be made illegal, Yep, it's EVIL Sh**

Post by cotten

There was a time when Kreem was the best (if you had to resort to a sealer, anyway).
But two things changed: I do not believe that today's Kreem is the old formula, and it is certain that the fuels have changed!

My wife's warhorse still has it in some severely abused tanks I 'customized' back in the early '80s.
Maybe I shall be lucky enough to get some gas back in them this season. The old Kreem had been durable so far...even in ethanol blends,..but is stained worse than an old china teacup.

Post by gearbox

I'm not going to stick up for Kreem and Cotten is probably right about the formula but, I had to resort to it in my tanks (after they were painted no less ) I tried all the tumbling and some acids but it always came back (rust ) to plug my strainer in the shut off valve . The only thing I did different was , I kept the rust remover in the tanks for a full week with a occasional shaking of the tanks ( tanks were loosely left on the bike) to stir them up , I used the Kreem immediately after the tank prep and this my have something to do with the out come is , I did not put fuel in them for a month , with tanks open to air. I know all can not do that but, my tanks look as white inside as the day I did them and no rust. I know by experience that time will tell the out come.I am using repo tanks and that may be why the rust was so much of a problem and this is not the first time I've used it.

Post by moose

put in small pebbels then wrap your tank in a towel tape it real good. then put it in a large blanket put your dryer on no heat and put it in. make sure your wife is not at home. With the small pea gravel it wont dent anything. Make sure the tank is in the dryer and not bouncing around you may need 2 blankets.


Post by 03roadking

I have a friend here in town that has a de-burring company He has these giant tumblers for polishing and de-burring I asked him what he would do
His reply
Find a hobby shop that deals in rock polishing or find a supply house that sells de-burring supplies they have all sorts of different media, some are cork some are ceramic, they have square, rectangle, round and all different weights, he said they sell for 1.50 to 2.00 per pound. You want enough to be about half full now go get the rotisserie off you barbecue you mount the motor so that it is secure then you need a piece of square stock that goes into the motor and you will need to build a support between the motor and the end of the shaft at the end of the shaft you mount a flat piece of plywood (what your building is a turntable on it's side) The flat board allows you to mount anything to it Gas tank, oil tank anything you want to tumble the inside clean. it will turn very slow so it doesn't damage the tanks inside Use 80% water 20% alcohol and a little liquid dish soap Use a non vented cap. plug the other tube If the cap leaks put some tape around it.
let it turn for an hour or two depending on how bad it is I just thought I would put my 2c's in

Post by gearbox

You can also use tumbling media for firearms brass , you can get it from most gun shops ,crushed walnut shells with or with out jewelers rouge and they make it in other types of media for tumbling brass.

Post by billy


I'm familiar w/the Dryer procedure...It works real well.

Timing IS critical however, as you posted "make sure your wife is not at home" Or comes home un-expectedly early !!! :o
How true that is !!!

Post by cotten

I recycle aquarium gravel because of its hard sharp edges; road pea gravel is often too rounded, and much of it is soft and turns to mud.
To scrub out the last abrasive particles after a final acid flush, I tumble with a slurry of cracked corn and baking soda. The corn gets sticky and makes everything easy to hose out. And don't forget some WD-40 real quick at the end.

MY apparatus is entirely dumpster scrap:


It took six sheaves to pulley down to about a rev per second. In theory it should eventually polish the insides, but I have let tanks run for several days 24-7 without penetrating some scales.
The worse have been rust and pits that were 'sealed' by ancient fuel turned to a resilient (and stinky) 'varnish'. The tanks required digestive solvent treatment even before abrasive tumbling would have an effect.
It seems rational that if scale doesn't come out after a couple o' days of tumbling, it won't.

And don't forget to pressuretest afterward!
(Less than 5 psi.)


Post by dremelts

I know this is not applicable if you're trying to save your paint, but if you are planning to repaint anyway, you could take the tanks to a powdercoater and have them run them thru their burn-off oven. This will get rid of any Kreem or varnish deposits inside the tank. It will also remove any paint and body filler from the exterior surface. Not sure that it do anything to the scale inside unless they sandblasted it.

Post by mbskeam

well I did the battery charger way today and it took all of about 15 min. to get the rust out. and my paint is still good.
to get the kreem out I let a tank soak for about 4 days, it then dissolved into the lacquer thiner, and came out when I drained them.
my tank sealer should be here tomorrow, I am going with Red-kote, as it does not seam to have the same fuel issues as kreem and por15, at least not YET.......


Post by cotten

Here's a red sealer that lasted for many years, until last:


Sealers aren't the problem, its the P4gas.
Sturdy post-'36 HD tanks shouldn't need one anyway.


Post by mbskeam on May 16, 2006, 5:02am

whats that a liver??? LOL
I thought that Bush told the gas company's that they could make gas as needed and ignore the EPA req. gas for the Midwest, as in P4....
what the hell is it made with acetone?
what was that liner?as in maker, brand.
my tanks don't leak but only trying to keep them from rusting,kinda a problem in the NW.


Post by cotten on May 16, 2006, 12:39pm

Brand unknown, although I knew the past three owners who rode the warhorse to death, and the sealer never changed until suddenly last summer.
The digestive component of P4gas is a detergent or injector cleaner associated with ethanol blends. The petroleum companies are tight-lipped about what we all end up breatheing.
I dried the 'liver' and cut many small equal pieces to test in babyfood jars with a dozen or so possible culprits, including straight ethanol and several local fuels. And a piece of Buna-N o-ring was added to each as well.
Ethanol itself did not affect either the sealer or the Buna-N in the slightest.
All fuels cause the sealer and Buna-N to swell, except the ethanol-free regular!
Straight ethanol is a great motorfuel, and would help our current demands if it were applied to mass transit buses or trains. But mixing it with gasoline is stupid. It takes all economic advantage out of it (costs more to produce than it returns), screws with our hardware, and associated additives are probably a hidden health hazard that our children must deal with.


Post by panpal on May 16, 2006, 3:21pm

I'm not so sure the redcoat is the same as it once was, probably the gas that is different. I have Kreme in a Honda tank, it's holding up, but I didn't like the way is seemed to bond. Almost like you could peel it if you worked at it a bit. The Por 15 seemed better and is holding up for now in the 59. Nice and hard like an epoxy with metal flake. A while back someone on Flathead power mentioned taking tanks to a place that tins copper pans. This sounds interesting if you did it before painting.

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Re: Fuel tank rust removal


Post by Billy » Fri May 19, 2006 6:38 pm

Whatever modern HD is using inside their gas tanks works Great.
Even in their New manuals, it states: "if tank inside is Dirty use hot soapy water & wash it out thoroughly"..
Like to find out what they use.. Cause I froze out a dent in a '94
FLHR & it never hurt the inner tank coating..

Maybe someone here knows ?

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Re: Fuel tank rust removal


Post by ridermike » Sat Sep 05, 2009 1:53 am

I found a rust removal product I am very impressed with. It is called EVAPO-RUST. It works as good as muratic acid (somewhat slower) but it is water based, biodegradable, and will NOT harm paint or skin. It is currently being used by the U.S. Army. It worked very well for me. I found it at http://www.theruststore.com.

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Re: Fuel tank rust removal


Post by 58flh » Sat Jul 31, 2010 3:06 pm

I have used vinegar along with quarter-inch size or smaller ball-bearings! Fill a pint in the tank, put about 2shotglasses of the ballbearings in, then shake! Repeat this untill your satisfied the rust is out. This will not harm your paint-job! After all is done blow-out with compressed air, protect your paintjob real good & buy a jug of tank-creme, protect your petcock threads & fill threads! then pour that creme in & roll the tank around real good ,let it dry for 24hrs. & your good to go. stay-safe----- 58flh

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Re: Fuel tank rust removal


Post by foundationapps » Wed Feb 24, 2016 5:58 pm

HI all, I have learned tons from the riders on this site. I like to contribute as much as my brain allows. My 48 needs some bigger tanks. So I went on Ebay and found a fine deal on a set of 5 gallon black tanks that appeared and are in great condition... on the outside. Inside was a combination of Kreem (I think) in the right side with some rust working through, and plain rust in the left side tank. Fuel tank mounts were fine. Phases explained as below:

1. Stage 1 Cleaning. Both tanks filled with ripe (old) gas to look for leaks. No leaks initially found. Both tanks heavily douched with water and soap to remove any old fumes prior to placing in the wife's dryer.

2. Filled both tanks with aquarium rocks (dry, about 1/3 full). Placed one tank at a time in a sleeping bag and taped that shut. x2 army ponocho liners, 2 pillows and an old foul army sock for luck added to take up space in the dryer so the tank didn't flop around.

3. NO HEAT. Tanks one at a time in the dryer for a total of 3 hours each. Intent was to remove rust only and superficial loose crap lining these tanks.

4. Stage 2 Cleaning. Worst tank, that with Kreem and other unidentifiable sealers and rust, filled with straight Acetone. Rotated and sloshed and left to rot overnight. In the morning, dumped the acetone out through a steel screen to recover the acetone, though somewhat polluted at this point.

RESULTS AT THIS POINT. 50% still coated in Kreem, most rust removed.

5. Stage 3 Cleaning. Recovered and polluted acetone replaced back in both tanks. Sloshed around and screened and re-poured into the tanks 2 more times. A large stiff bottle type brush was used to scrub loose any Kreem residue or whatever else was in there.

RESULTS: After a 5 hour pour out and replace process, ALL rust removed that is visible to this point. Still some Kreem left behind. Left side tank that was without any coating is clean at this point. Sprayed inside with WD-40 to prevent rust while the right side tank was completed.

6. Stage 4 Cleaning. (x3 days at this point). NEW Acetone poured into Left side tank. Left this overnight. In the morning, acetone poured through screen, a glob mass about the size of a golf ball if you wadded it into a mass.

RESULTS: While some spotty Kreem remains, all rust and other residues appear gone. Considered chemically clean at this point. Next stage.

7. Stage 5. Cleaning and prep. Aquarium rocks with nuts and small bolts added to gas tank. (Right side only, left side still sitting with WD-40 inside). Taped back into sleeping bag and padded as explained above. 3 hours of cold air tumbling.

RESULTS: All rust removed, spotty on the Kreem (or whatever that crap is). Acceptable for me.

8. Full wash out and rinse. If no leaks, will NOT coat with a tank liner. I add MMO to the fuel, so rust shouldn't be a problem.

Will update.

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UPDATE: Re: Fuel tank rust removal


Post by foundationapps » Tue Mar 01, 2016 10:17 pm

Follow up to last post on the tank cleanup. After cleaning as much as possible and several fuel flushes, all was as clean as I was willing to complete.

Sealed the tanks and pushed in about 5 PSI of air to check for leaks, there were none. I opted OUT of adding any sealant. Adding MMO to the fuel was going to have to be good enough to prevent rust.

Reconnected the tanks, added a clean screen to the petcock, open the valve. Fuel flowed at about 50% (my guess), it clotted off. Drained the fuel, removed the petcock and found a clot of unidentifiable crap INSIDE the valve (maybe from before the tank change?).

Tank reassembled, machine has been running perfectly, after I corrected an intake manifold leak. (Thanks Richie).

FOLLOW UP ON AQUARIUM ROCKS... If you pad the tanks well enough (1 at a time), I taped mine into a sleeping bag, then packed poncho liners and pillows around the tank for additional silencer effect.... wife thought I was doing laundry so I got extra bonus points for doing laundry. I folded the poncho liners and acted like an idiot when she asked me if I actually washed the pillow too!! LOL. She never caught onto the tanks in the dryer being the center of the action.

Mission Complete.

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