Extending the life of a new fuel tank.

[Gazzar]

My fuel tank has died. Partially as I didn't sous it in cavity wax a few years ago when I saw it rusting, but partially because it's a carp design that traps moisture been two unprotected sheets of steel.

I'm getting a new one. 

What can be done to extend its life?

My current thinking is to inject Dynax wax into the three channels in the outer cradle, stopping up the edges, so that is full of the wax, but what about the exterior? How good is the standard paint? If I cover it with under body wax, will the paint flake off and take the wax with it?

[Snagger]

I’d have it blasted, red oxide or zinc rich primed, then paint with a decent top coat like POR15.  Once that is all dry, you can spray wax into all the nooks and crannies to protect the bits paint can’t reach.

I think it might be a good idea to protect the inside too, before the edges start rusting by the welds.  The POR15 tank lining kit would do that well.  It’d be en expensive tank buy the end of all that, but should see out the apocalypse.

[Gazzar]

That's ideal. I'll be doing mostly that for the lightweight.  But for this I'm not able to do all that, I want to be back on the road as soon as possible, so I'll see how bad the factory paint is, and take it from there. If I get anther twenty years or of it, that will do until I convert it to electric.

I don't think the inside needs doing though, the diesel will stop it from rotting. Petrol, on the other hand.....

[Anderzander]

There are a couple of folk making stainless tanks for the 80” - are they out there for the later series ? 

[Maverik]

I was thinking about this earlier only independently of this thread, and I hatched a plan. 

Get a standard tank weld some 1/8npt nipples on it, in some tactical places and send it to be galvanised... once done tap out the holes and inset 1/8npt blanks.

Jobs a good un.

[Gazzar]

Ummmm, could it be that simple? The steel is thin, distortion welding the bungs in, and the galv......

I'm tempted to commission a stainless tank.

Or even MIG one up myself, with an integrated cradle. 1.5mm top and sides, 3mm cradle as base.

One day........

[smallfry]

You should have waxoyled the tank inside 

Series tanks used to be galvanised inside and out, ISTR

[Mossberg]

6 hours ago, Gazzar said:

 

I'm tempted to commission a stainless tank.

Or even MIG one up myself, with an integrated cradle. 1.5mm top and sides, 3mm cradle as base.

One day........

If you make your own then I would suggest tight welding if you can.  You can tend to see any potential leaks with tig and then go over it if you need to.

I used to make water tanks in galvanised mild steel. That was a pain due to having to clean all the galv off, but this was done mig and it was a pain. They tended to leak where you started/finished a weld and anywhere you touched the weld with a grinder - as soon as you took the surface off the weld it would leak. We used dye penetrant to test them. I got to the stage where I could look at a weld and tell where it was going to leak.

I never mig welded any stainless tanks so I can't comment if this is different to wheen I did mild steel.  I was a sheet metal worker ot the time, not a welder, so perhaps a more knowledgeable welder could comment on if stainless mig is different from mild steel. 

I have considered making a stainless tank for the defender but haven't looked into it with enough detail yet. The thing that puts me off more than anything is filler tubes and fitting senders etc.

I must admit I find it crazy that two skins are fitted so close to each other without the ability to split them for painting and maintenance. 

[Gazzar]

8 hours ago, smallfry said:

You should have waxoyled the tank inside 

Series tanks used to be galvanised inside and out, ISTR

There is a layer of something, tin? zinc? on the older series tanks, but the rust still happens between the skins.

 

 

This photo is of the waxoil inside my chassis. It's delaminated and turned into gum.

 

Which is why I've had to repair the chassis.

 

If I get twenty years out of this tank, like the last two, that will do.

[garrycol]

50 minutes ago, Gazzar said:

There is a layer of something, tin? zinc? on the older series tanks, but the rust still happens between the skins.

 

Yes the tank was soldered to the bottom plate.

[smallfry]

2 hours ago, Gazzar said:

There is a layer of something, tin? zinc? on the older series tanks, but the rust still happens between the skins.

This photo is of the waxoil inside my chassis. It's delaminated and turned into gum.

If I get twenty years out of this tank, like the last two, that will do.

I dont know if its solder, but its definitely coated all over, looks like galv to me, and like yours had become porous between the skins, which is why it was changed some years ago. Still up the garden because Wrens nest in it now. Diesel ones still rust, because the fuel sits on top of the water.

Anyway, I dont like Waxoyl because it does this. I have cut up a couple of vehicles that were treated, and seen that it sits on top of debris in the sills (old cars were not painted inside the box sections) and offers nothing towards corrosion protection. It dries out too, despite what they claim.

I would be inclined to stand there with a hair drier (when Mrs Gazzar is out) and warm it while using Bilt Hamber S50 on it. Hopefully it will creep between the panels. Or get it galved as suggested

[Gazzar]

Warning it up is a good idea. When the new tank arrives I'll sit it on the workshop heaters for a day, and dry out any storage moisture. Dynax is supposed to wick into gaps and never stop creeping, so that, the heat, and the injection straws should get wax in everywhere.

 

Never again will I use waxoil.

[Maverik]

14 hours ago, Gazzar said:

Ummmm, could it be that simple? The steel is thin, distortion welding the bungs in, and the galv......

I'm tempted to commission a stainless tank.

Or even MIG one up myself, with an integrated cradle. 1.5mm top and sides, 3mm cradle as base.

One day........

Distortion can be kept to a minimum with some mindful welding, I'm going to give it a go when I have a bit of workshop space to play with.

[Gazzar]

I'd consider doing the tank and cradle separately in mild, and getting it dipped.

But not a shop bought tank.

The filler pipe would be very vulnerable, though, as would the various vent pipes, though they could be done as bungs to allow for galv draining of the tank.

There is also the risk of the sulphur in the diesel interacting with the galv.

It's marginal in my mind, I think a good zinc rich epoxy coating might be smarter.

[Nonimouse]

I'd just lather it in Lanoguard every year or so - tem minutes work

[Gazzar]

I know. It's my neglect that contributed to this. Too much on. 

[rednaxela]

On 12/11/2021 at 10:28 PM, Gazzar said:

My fuel tank has died. Partially as I didn't sous it in cavity wax a few years ago when I saw it rusting, but partially because it's a carp design that traps moisture been two unprotected sheets of steel.

I'm getting a new one. 

What can be done to extend its life?

My current thinking is to inject Dynax wax into the three channels in the outer cradle, stopping up the edges, so that is full of the wax, but what about the exterior? How good is the standard paint? If I cover it with under body wax, will the paint flake off and take the wax with it?

 

If you are getting a repro/new tank,  as Snagger said, sandblasted, good paint system. But then  after that, inject wax into the channels like you said, but then use a seam sealer around the seams, then spray a good thick coat of stone chip paint over it.  Then, some good paint over the stop chip.  

 

It's easy to suggest galvanising for stuff like this but it's best if one has loads of other things to get dipped at the same time.

 

I have an allisport alu tank on my SIIa.

Edited December 13, 2021 by rednaxela

[Tanuki]

Stainless is the obvious answer. The tank on my classic-car is known to rust-out after 20 years or so; there are a couple of suppliers who produce stainless-steel tanks with proper roller-welded construction [and proper internal baffles to stop fuel-slosh: 15 gallons of fuel slopping from side to side during 11/10ths cornering can be a bit of a problem on-track] and they will never be a rust-problem.

Surely there must be someone out there who makes stainless-steel 'series' tanks as a £250 fit-and-forget option?

[Maverik]

https://www.ebay.co.uk/itm/Land-Rover-series-2-2A-3-Swb-stainless-steel-petrol-fuel-tank-1958-1985-/264279429107?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l6249&mkrid=710-127635-2958-0

[Gazzar]

SWB. Mine's a LWB.

Hopefully the tank will get here tomorrow. It's getting wax, that's it. I would love to get the thing blasted and epoxied. But that will drag the job out for weeks, and I need to get back on the road.

 

I'll get the lightweight tanks done properly.

[Retroanaconda]

Could a Td5 tank be made to fit with a little modification and some brackets? Would probably cause issues with the crossmember but at least it could never rust. 

[Gazzar]

It's plastic, isn't it? The ideal, in my mind, would be a plastic tank that slots into a series cradle.

[missingsid]

20 minutes ago, Gazzar said:

It's plastic, isn't it? The ideal, in my mind, would be a plastic tank that slots into a series cradle.

Or fits inside a series tank with the top open?

[Gazzar]

That would be nice.

I'm having second thoughts about sealing the cradle.

The top of the interface isn't easily assessable at the front.

It's covered by the strip of angle. I'm thinking that when water gets in it won't be able to get out.

I'll have to rely on the Dynax, I think.

Bad design. But I need to get the truck out of the workshop.

 

[Maverik]

23 hours ago, Gazzar said:

There is also the risk of the sulphur in the diesel interacting with the galv.

Now I understand why you where so flippant with my suggestion, I had no clue that diesel fuel interacted with zinc/galvanised finish.

School day for me, and glad I now know.

Back to plan A of making a stainless one its is then.