g741.org

Was over on the G503 now asking over on the G741:

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?

Later post:

There are a number of ways to kill rust. I have not tired molasses yet but have used phosphoric acid. On this fuel tank I want to use something a little less aggressive and thought the molasses might be better.

This was the first video I saw that got me interested:

http://www.youtube.com/watch?v=KZCFcxf5IBw

Then I had to look at the next one:

http://www.youtube.com/watch?v=8-gBAjEga1s

Alan

I use a product called EvapoRust for most of my rust removal projects. It you leave a clean but rusty part in it for about 48 hours it will remove every bit of rust. It will sometimes leave a little bit of a black film that can be removed with a wire wheel without much effort. The metal underneath is always bright and clean even if it was heavily pitted before. It's also safe and easy to work with (no fumes, not caustic or acidic).

Many parts stores have it, and I think Tractor Supply does as well. A gallon is less than $25. I reuse it several times.

I haven't tried it in a fuel tank yet, but I plan to try it with mine. I think a gallon would be enough for a fuel tank, just leave it in one position for a couple of days, then roll it to a different angle for a couple days, etc.

For heavy rust, strap the tank to a concrete mixer. Add a mix of gravel and water, plug up the holes, and let run for an hour or so. This method saved my tank when electrolysis and Evap-o-rust failed.

No chemicals, no sugar, no residue.

It did, however, annoy the neighbors.

http://youtu.be/pC4Dt9um7_Y

you could also try electrolysis. Ground the tank filled with water and baking soda and suspend a couple piece of steel in there. Connect to a battery charger and let it sit for a few hours

W30bob on here tried the molasses on some combat rims with less then desirable results, I'd go another route

Hi Alan,

You have an interesting problem to be sure. As Tuko said, I've tried molasses and was less than impressed with the results. In your case where you don't have access to the whole inside of the tank I don't see how you'd get all the molasses crud out.....which could make more problems for the rest of your fuel system later. In the videos the guy has to pressure wash the crud off. If you just left it there it would clog your fuel filter(s) for sure.

A couple things to think about........there are professional tank sealing services offered by VPW and others, but they're expensive. But the takeaway from those services is they cut holes in tank to get access to all the spots the baffles hide, and then weld the tank back up when done. If they couldn't do that they wouldn't offer a lifetime warranty. Any means to clean the tank without having access to the whole tank may provide questionable results. The band of rust you have in the top of the tank is going to come right back if the rust isn't fully removed and the tank sealed. Condensation will cause it come right back on the unsealed metal. But I don't know if that's such a bad thing. If you keep the tank full that band of rust won't get any worse and if you drive your truck the fuel sloshing around will help keep the rust at bay.

Electrolysis probably won't work, as it's a line of sight process and you have just about no line of sight into the tank. But it will clean up the outside of the tank just fine.

I love using Evapo Rust, but in this case you're going to need a lot to cover that rust band in the top of the tank. The band of rust must be continuously submerged in Evapo Rust for it to work, it's not like Naval Jelly where you can wipe it on and then hose it off. So depending on the dimensions of the tank, it may take a few gallons.....at $25 per gallon. You may be able to rig it where two gallons covers one corner of the tank if you prop it up right, and then every day you move it to cover the other corners...........if you know what I mean.

I would say you're best options are (1) bringing the tank to a radiator repair shop and have it boiled out, or (2) use Muriatic acid. Nasty stuff for sure, but it does work.....but you have to fully neutralize it with baking soda, not just flush it out with water......or you're going to have an even bigger problem than you have now. Or there's the third option you won't like....cut holes in the tank to access the baffled areas, sandblast the bitch, and then weld her back up. Not fun for sure.

Bottom line is there is no single fool-proof solution to what you're trying to do (other than fork over $500 to have it professionally sealed). One last thing.......if you decide to go the Evapo-Rust route there is a cheaper alternative. You can buy a product in concentrate form that works as well as Evapo-Rust and save some big bucks. The downside is you're going to have a couple gallons of this stuff laying around when your done with your tank....but for things that need lots of solution these guys are the way to go. Here's the link;

http://www.rustdepot.com/Index.htm

I also have on my list of rust removers to try something called Oxylic acid. I've read good things, but then you can read good things about anything if you look hard enough. So I can't comment on how well it works yet. But let us know what you decide to do..........it's good to get insight into these processes and products from people you can trust.

If you have any questions just shout.

regards,
bob