sealing rusty tanks?

[surfdude]

holy cow, cotten, a tank tumbler! cracked corn slurry?! about the only way i could compete with that is to maybe use some oatmeal and have my 8-year-old shake it for a while. so much to learn...

actually i forgot the most important detail -- original paint tanks on my '64, so splitting and fixing the inside is not something i am qualified or want to do. still advise throwing some nuts and bolts in there and giving it a good shake? i guess getting off some rust is better than leaving it. no sealer, though, huh?

[T. Cotten]

Yes, all that soldered tank stuff is irrelevant, as your 'modern' HD tanks are damn sturdy.

Get the rust out, and keep her topped off, and you'll do fine.

...Cotten

[dneagle]

Fuel Guru AKA Cotten

Cotten,
If nobody has said so...Thank you for your many responses to fuel related issues. Your advice is both relevant and applicable (got me an edgikation!!). Am starting on the fuel systems redo for my '59FLF this spring, so will be leaning on you for tips and parts if I may. LeakyPete

[Kojack]

Nice tumbler, Cotton. I've been saving an old barbacue grill rotesserie motor for a similar contraption. Guys, I remember having my Sportser tank professionally dip stripped years ago and inadvertantly removing the factory sealer so it's safe to say that sealers are not just an aftermarket cure for rusty tanks. The factories also used them for rust prevention on bare steel tanks. A freind of mine who does gas tank repairs claims that any of them can be easily removed by washing the tank out with acetone (not sure about the POR-15 which I've heard is the best). I believe that terne plate, which is corrosion resistant, is only used in soldered tanks. Welding terne plate destroys the coating and creates a contaminated weld.

[Tommo]

When we came to the USA in 2003 five of the seven bikes had tank sealer in their tanks. Once we got near Milwaukee and started using the "Environment Freindly Gas", which I understand is Corn Ethynol Based, the trouble started. Four of those five bikes were using POR 15 and after a few days most of that product was a gluey mess in the bottom of the tank and giving all sorts of petrol blockage troubles. The fifth bikes tanks had been treated with an aviation quality sealant and done as a favour at a workshop that must remain anonymous.
I am still trying to find out exactly what that good product is but suspect it is a military product.
Tommo

[surfdude]

i'm with dneagle -- thanks cotten! the knowledge you guys share is why i joined in the first place.

[inrustwetrust]

Unfortunately, aviation sloshing sealers are not an approved method of sealing gas tanks in airplanes anymore and probably totally unavailable. If the tank is dry and has been dry for many years, use molasses and water. 12 parts water and one part molasses. Molasses and water is totally ineffective if there is even the slightest trace of petroleum in the metal. Give it about a week and DO NOT seal the tank, the fermentation process creates gas and could cause an explosion from pressure.
Using any phosphoric acid based solution will take all of the remaining tin out of the tank.
As was mentioned previous, keeping it topped is the best preventative to rust. I have always used 100LL avgas, the best reason being is that it stays good for many years, as pump gas is bad after a couple of months. It smells good and stays tighter in the system than pump gas (seeps less)

[TMarony]

If you are interested, there is a company in eastern PA that will totally redo your tank. They open the tank via the facotry weld, sanblast the interior, weld any holes closed (or add a plate if the rusted area is to severe) treat the interior to the tank with a baked on coating, then re-weld the tank back toether. Guarentee is that the
tank will not leak or rust again. My gas
tank was very rusted (sat for years) and
had a weak area in the bottom. After cleaning, plate was added, tank treated with coating (which is baked on) and rewelded. Looks just like new