Molasses Tank Cleaning

[SturmTyger380]

I have a 60 gallon fuel tank that I have let sit full for 24 hours with lye inside. I rinsed it out this morning and now it is very clean inside. Above where the fuel sat for years about 1/4 of the top part of the tank there is a band of rust.

This tank has a series of baffles inside so I can't really get to every area of the inside and I don't want to cut holes in a tank that was holding liquid without leaking.

I plan on finding some sharp stones and shake those around inside the best I can to remove any rust I can get loose from the rust band.

Then I thought of using a solution of molasses and water to fill it up and let it soak for a week or so.

I have watched videos of the guy in Australia that soaks his old car body panels in a solution and then power washes them to remove the molasses. I can't power wash inside my tank.
My question is how hard is it to remove the molasses when I am ready to clean the tank? Would really hot water remove it from the insides?

Ideas? Alan

 

[1985mustanggt50]

How about some of that stuff that you coat fuel tanks with? I cant remember the name right off but I have used it on many motorcycle tanks that had pinholes. You pour it in and shake the tank

 

[SturmTyger380]

I plan on doing that for my final step. The instructions for it say remove all rust that could detach from the lining.

Current step - Remove and kill all rust.

Then:
Rinse out with Phosphoric acid - This will neutralize the effects of a rust killer and etch for the liner.
Rinse out with Acetone - This will remove the Phosphoric acid and any oils that might keep the lining material from sticking.

I have done a tank like this before but it was one where I could get inside and kill and see that the rust was gone.

Alan

 

[MarcusOReallyus]

I think good hot water and some laundry detergent should do the job. Repeated applications and lots of rinsing, of course.

But you'll need to be sure to get it all, or your lining won't stick.

I wouldn't put the stones in there - you'll have a very hard time getting them all out, and I can't really see them doing a lot for you anyway.


But wouldn't the phosporic acid take care of the rust anyway? That's the active ingredient in Naval Jelly.

 

[ducer]

If you search this very same section infact 2 threads down from this one (currently) there is some very good advise on how to take care of your in tank rust problem.

Denny

 

[Trailboss]

Remember how folks used to kill engines with sugar in the gas tanks? I don't know if that prank works with diesels, but molassas is just liquid raw sugar. I wouldn't take the risk. The inside of a fuel tank is not the same as the outside of a body panel.

 

[Tow4]

I use ZEP rust and lime remover from Home Depot. It will remove the rust. I keep a 5 gallon bucket with ZEP solution in it to clean small parts. I let them sit a day and then pull them out and hit them with a brass brush while I rinse with water. If all the rust isn't off, I throw it back in the bucket for another day. The part will eventually clean up just soaking, but I find brushing off the loose stuff speeds things up.

I have also used small rocks and ZEP to clean out a motor cycle gas tank and it worked fine. You need something to remove the rust after it is softened by the ZEP, that's where the small rocks come in. The rust dissolves in layers so an abrasive (rocks) to knock off the loose stuff speeds things up.