Fuel Tank - aluminised steel Vs mild steel

[Mellow Yellow]

G'Day All,

I'm looking to extend my touring range with either a larger main tank or an auxiliary tank (or tanks) in my TD5 110.

Long Ranger tanks and Brown Davis tanks are both made with 14 gauge aluminsed steel. Presumably to avoid the possibility of rust on the inside of the tanks ?

I've been talking to another manufacturer who doesn't use aluminised steel nor coat the inside of his tanks in any way. He says that this should not be a problem provided I always maintain at least a small amount of diesel in the tanks.

I'm very wary about fitting tanks that have any potential to rust internally.

Any advice would be appreciated.

Thanks.

[Dougal]

If you keep your tanks free of water, then they'll stay free of rust.
The aluminised steel won't be aluminised where it's welded, so the critical parts remain unprotected.

[Mellow Yellow]

You'd be right about the loss of aluminising along the welds.

I'm also a strong believer in preventing a problem arising rather than fixing it after it arises. So keeping water out of the tank in the first place is good sense. However, is it possible to keep all moisture out of a tank? Condensation on a cold night for example.

If it's not possible, does it really matter? Does the diesel fuel itself protect the steel.

[Dougal]

You'd be right about the loss of aluminising along the welds.

I'm also a strong believer in preventing a problem arising rather than fixing it after it arises. So keeping water out of the tank in the first place is good sense. However, is it possible to keep all moisture out of a tank? Condensation on a cold night for example.

If it's not possible, does it really matter? Does the diesel fuel itself protect the steel.

The problem wouldn't be condensation as much as introduced water which is left to sit on the bottom of the tank.
Condensation can be minimised by only opening the tank when needed and filling it completely instead of just small amounts. The more you open a tank, the more air gets in.

[steveG]

You can get fuel resistant coatings that will completely seal the inside of the tank. I've used them in the past on aircraft fuel tanks.
An example is 3M product number EC776.
No idea what they cost though...

Steve