internal rust in fuel tank / tank liners

[kiwikeithfj]

Hey I know the issue!
I have a rust problem too. Last sunday I spent an hour on the side of the road removing the rust and scale from the fuel filter and petcock. I didn't even know I had a rust problem till then! 15,000 km in two years and it never once showed up.

Anyhow......
I now have the tank off and I did blast the inside with water to remove anything that was loose. There still appears to be some in there though.
I was thinking about one of those "tank-liners" that you have been talking about. Talk about a timely warning. I have used a couple of different things on panel restoration on cars but was a bit hesitant to try them, just as well I guess.
Research suggest the best way to remove the internal rust is sand, water and a whole lot of shaking. Alternately a handful of nuts and the same treatment. This seems a bit time consuming and I am nothing if not lazy.

The real question I have is this:
Is there anything that can be used to remove the rust, but not actually leave a coating that might later cause even more problems?
I recall a product that used to be available here in Kiwiland called Jenolite. I believe it was a phosphoric acid based solution. The big advantage was that it was water soluble and could thus be washed out once it had done it's job. This no longer seems to be available. Is there anything similar that anyone knows of.
I have already thought of the fact that I would have to remove the fuel gauge sender, petcock and fuel filler to avoid damaging them. I am waiting for new gaskets before I start.
In the meantime some suggestions would be great.
Keith
'91 FJ1200

[Steve_in_Florida]

We're dealing with this very thing in one of the gas tanks for an (otherwise pristine) Indian Chief inline 4-cylinder from the 1940's. The left-hand fuel tank is beautifully painted, but otherwise full of rust with evidence of a previous internal repair.

One of the bosses cronies brought over a battery charger, steel bar, and some sodium carbonate (NaCO₃) powder.

As I understand the procedure:

     Remove as much existing rust and rust particles as you can, though physical means (agitation with chain or nuts and bolts).

     Fuel tank openings sealed (except for fill neck).

     Sodium Carbonate (NaCO₃) mixed with water, and added to fuel tank.

     Steel bar sandblasted, wrapped with porous plastic over wrap (to prevent direct contact with tank walls), and immersed in NaCO₃ solution.

     Battery charger positive clip connected to steel bar, negative clip connected to fuel tank, power cord plugged into the wall outlet.

     Small amperage applied to solution over a span of a few days.

     Rust particles "magically" migrate through electrolyte, and deposit onto steel bar.

     Depending on the severity of the rust, the electrolysis process may have to be repeated.

     (Hopefully) the internal fuel tank surface will then be rust-free, and ready for further treatment and (possibly) a liner-type product.

In the case of this Indian Chief, the tank is pretty far gone internally, but has a beautiful paint job that matches the rest of the bike. We're trying everything that we can to save it, but are possibly looking at replacing both tanks anyway.

Once the rust process takes hold, you'll never totally get rid of it. Tank liners just cover up the problem, and become a nightmare for the next guy.

If the rust is as bad as you state, you might want to start looking for a replacement fuel tank, while they're still available.

Regards,   

Steve

[kiwikeithfj]

Hi Steve,
electrolysis! There's an idea I hadn't considered.
Actually the rust is not too bad, mainly in the seam at the bottom edge of the tank. Just like your Indian the tank looks pristine from the outside.
It is high summer here and I am itching to be riding so I might take the risk  of potential fuel blockages ( let's face it it has done 15,000 km since I bought it and this is the first time I have had any issues ) and put back together for now, till winter comes and I can stand being without it for a week or two to do the job properly.
I plan to remove any loose rust with the old nuts and miscellaneous parts and a good shaking. I was then looking at some sort of method to remove the last of the surface rust. The Electrolysis idea seems like a great idea as it does not leave any other chemicals behind.
Thanks again,
Keith

[giantkiller]

This is the inside of the tank on the bike I just bought for my turbo bike.

[FJmonkey]

Bugger....

[giantkiller]

Yah going to try my hand at making an aluminum tank inside a fake shell. Have to put the tank for water/methanol injection in there and probably the pump too. As well as intake tubes. Hoping for 2-21/2 gallons of fuel.

[Ponty]

I've tried a tank liner system 3 or 4 times - the tank actually was leaking in each case. It was a 3 part system, clean, etch, liner. Worked okay twice, didn't work twice. Very tricky and time-consuming, and cost about £40. Better to buy decent second-hand tank or get an expert to cut out an rebuild I think. cheers, And.

[Ponty]

Also - I didn't want to put a long post on because I've tried a couple of times and it didn't work! Electrolysis works ok but when I did it the tank rusted again very quickly - as though the process had speeded up the rusting - I don't know if there's any science here? I've read that you should connect the charger to a battery and then to the electrode/tank so that if it shorts out it's not too drastic. Also the fumes coming off might be inflammable so better out of doors. The nuts and bolts works well. Use loads of them, all different sizes so they get into the corners. Count them in and out. You can shake mechanically - use a cement mixer or even secure the tank to a jacked up car wheel. 'Secure' is the operative word here - I've never tried this. Use hot soapy water in the tank with the nuts and bolts - you can use Jenolite or Coca-cola or Cilit Bang or anything with phosphoric acid in it, but I haven't found this makes much difference. Important to rinse the tank with lots of running water after, then rinse again several times with Metholated spirits, which 'dries up' the water. I usually dry the tank then with a hot air gun but I'm sure this is dangerous! Put a little diesel, WD 40, 2 stroke oil or White Spirit in the tank to keep it rust free if you're not actually using the bike. I'm trying out a product for lawnmowers that's supposed to keep the water in the petrol in suspension this winter - I'll post how it works in the Spring. Cheers, And.

[giantkiller]

After cutting out the bottom I think it would be easy enough to make another bottom. And weld it back in. After cleaning out the tank. You could probably coat most of the top. So it won't rust down to close to the weld.
I put a little marine 2stroke(tc3?) oil in every other tank. Supposedly helps keep the water suspended in the gas to help remove it. And I figure a little oil to coat the bare steal won't hurt.

[Mark Olson]

Stuck it in the dryer one time to rotate with no heat setting. sealed it in a plastic bag , no leaks and wife never found out.

Also I remember a post of someone who welded 2 tanks together to increase fuel capacity.

Remember bare metal rusts fast. so spray with wd-40 immediately or some other oil based product . like solvent or diesel fuel.

[ribbert]

Has anyone ever looked into using a fuel bladder inside a tank?

Noel

[Brook]

..... Por-15   

[Timbo-1]

..... Por-15   

+1 for por 15. Have used the treatment on several tanks and works really well.
Follow the instructions and you will be amazed.

[JMR]

Also - I didn't want to put a long post on because I've tried a couple of times and it didn't work! Electrolysis works ok but when I did it the tank rusted again very quickly - as though the process had speeded up the rusting - I don't know if there's any science here? I've read that you should connect the charger to a battery and then to the electrode/tank so that if it shorts out it's not too drastic. Also the fumes coming off might be inflammable so better out of doors. The nuts and bolts works well. Use loads of them, all different sizes so they get into the corners. Count them in and out. You can shake mechanically - use a cement mixer or even secure the tank to a jacked up car wheel. 'Secure' is the operative word here - I've never tried this. Use hot soapy water in the tank with the nuts and bolts - you can use Jenolite or Coca-cola or Cilit Bang or anything with phosphoric acid in it, but I haven't found this makes much difference. Important to rinse the tank with lots of running water after, then rinse again several times with Metholated spirits, which 'dries up' the water. I usually dry the tank then with a hot air gun but I'm sure this is dangerous! Put a little diesel, WD 40, 2 stroke oil or White Spirit in the tank to keep it rust free if you're not actually using the bike. I'm trying out a product for lawnmowers that's supposed to keep the water in the petrol in suspension this winter - I'll post how it works in the Spring. Cheers, And.

A piece of chain is easier to remove than a load of free nuts and bolts

[Timbo-1]

..... Por-15   

+1 for por 15. Have used the treatment on several tanks and works really well.
Follow the instructions and you will be amazed.

http://www.por15.com/POR-15-Fuel-Tank-Sealer_p_64.html