Wonder compound for sealing a fuel tank from the inside?

Murv

Murv

Well-Known Member
Joined
14 Nov 2012
Messages
2,127
Location
Kent
Visit site
Is there anything on the market that can be sprayed, or brushed, onto steel that still has diesel residue on it?

There is a possibility there is a pin hole somewhere along the base of the tank, so before I go in with the wire brush and CT1, is there anything better out there?

The tank cannot be removed, nor can I get to it well enough to solvent clean it properly, so it needs to be something that meets the criteria above.
It's also a fairly large tank at around 550 litres so small patch kits probably wouldn't be viable.

I very much doubt there is anything, but doesn't hurt to ask!
 
Long term there is no practical alternative to removing the tank and replacing it with something better! You are suffering the consequences of a decision years ago to fit a mild steel tank which will eventually corrode - and then build a smart boat around it!
 
trouble with anything you chuck in a tank to seal it, it will find the biggest leak of all eventually, the outlet. Take the tank out to sort,a different story, but in situ you might get lucky with a two pack tank repair on the outside - if you can find the leak.
 
my 'guess' is that if the tank has got to the state where it has suspected 'pin hole leaks' then it must be on its last legs. treatment may delay the inevitable but could invite a really serious loss of fuel at a critical time.
Sorry!!
 
Murv said:
There is a possibility there is a pin hole somewhere along the base of the tank, so before I go in with the wire brush and CT1, is there anything better out there?
Click to expand...
Faced with the same situation (but not in the same type of boat) I replaced both tanks . The thinking was if one tank has gone the other may be at risk. The tanks were accessible in my case.
On another forum there was a write up about a boat where the tanks were tricky to get out of the boat. I think they may have cut the tanks to get them out . The replacement tanks were made slightly smaller. I don't know whether that sort of idea would help in your case.
 
Thanks all.
Dave, thanks for the link, they don't supply anything that doesn't require a thorough solvent clean, but that may be the next step if it doesn't solve it and may be possible after cutting more access panels.
Trevor, great idea. If plans A and B fail, I think that's the route I would take. It would require some extensive cutting and removal of the baffles, but would still be a better option than rebuilding the interior of the boat.
There is no way of cutting the tank up without risking damaging the boat, so removal is either paying somebody to rebuild the interior, or removing an engine. Both options would be expensive and take the boat out of action for several weeks.

The tank is actually in extremely good condition, there is no internal corrosion or any sign of seam failure.
My Year boat should have the alloy tanks fitted, which fail earlier than the steel ones, so I suspect mine may have been changed at some point.
The leak is probably down to a previously undiscovered drain bolt, but as the tank's now empty and clean, it seems worthwhile running a bead of sealant around the inside, just in case.

The other tank is actually fairly easy (relatively) to remove, so that will be drained, cleaned and inspected next Year.
 
Last edited:
I seem to recall the Aviation industry had problems with the wing tanks on Boeing 767/747, they used an additive to the fuel and they self sealed. It was not my area so cannot be more helpful, but more research may give some clues.

Cheers Peter
 
pvb said:
But the instructions say the surface has to be clean, dry and free from grease etc. Doesn't sound like you could paint that on to a surface with diesel residue on it.
Click to expand...

That applies to any sealant or like material. Even epoxy must be applied to a surface that is clean, dry and free from grease.
 
pvb said:
Agreed; maybe you didn't read the original question.
Click to expand...

Do you know anything that can be painted into a diesel contaminated tank that can seal it ?

If not why criticise others who try to come up with a solution.

The OP has the choice to replace the tank or degrease it and seal it with something like I suggested. There are several options that would allow the OP to degrease the tank. He says that the tank is now clean and empty so he could used what I suggested or just put a bead of sealant in the corners as he posted.
 
When our anti-syphon valve failed and the engine took 5-8 litres of sea-water into the sump the oil, black gunge etc all floated to the top. The sump itself when I took it off was immaculately clean - clean enough to eat your dinner off.

As a thought with your tank you could half fill it with water, float the diesel to a level where it can be syphoned or wicked off then pump the water out. Water is obviously much easier to remove than diesel and can be finally dried with a small fan heater.Your tank should then be clean enough to take a coating of sealant.
 
Thanks all, I appreciate that it was a big ask!

Quick update, as quite rightly posted above, even CT1 will not stick to diesel. Well, it does, but only in the areas where it's easy to get to and run a nice firm bead along with a finger. In the more remote corners, where I'm effectively trying to run it with the aid of a stick, it just doesn't take properly.
So, plan B, which is to clean all traces of fuel out and then seal the thing properly with something that can be liberally brushed, or sprayed, on.

I very much like the flooding it with water idea, but I wonder if it would really lift all the fuel out of any little crevices?
As stated before, there are a few areas of the tank that I can't quite reach by hand.

I do have at my disposal, an insanely powerful wet vac, and a small pressure washer. Is it worth spraying the thing as best I can with something like Bilge X, then pressure washing and vacuuming the water out?
Or, is it worth my while hiring a steam cleaner? I've never even seen one, but I'm assuming they have some sort of lance that emits a pressurised jet of steam. If that is the case, would it "wet" the tank enough that the diesel residue would run to the bottom for vacuuming?
 
You must log in or register to reply here.

Share this page

Top