Which resin is the best for sealing diesel fuel tank?

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Boater On Thames

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I am going to pour a thick layer of resin into one of my diesel fuel tank bottoms to stop the annoying slow leaking. Do you know which resin should I use? Let me know.
Many thanks!
 
I don't want to 'rain on your parade' here, but I don't think that this is a very good idea.
First of all, please note that you would need to clean the interior of the tank VERY well, otherwise nothing will stick to it, not even epoxy.


Can you let us have some more information please?
Here are some questions to start off with - I am sure that others on here will add some more.

Make and size of boat?
Size of diesel tank, construction material, location, how accessible is it?
Do you know why it is leaking? Are there any visible stress cracks, or pinhole corrosion, or.......?
Does it have any access panels in the top of the tank?
Do you know where the baffles are in the tank, and how they are constructed?
Is it possible to take the tank out, or would it have to be cut up in situ to remove it?
If this is the case, would it be possible to fit two new smaller tanks instead?
 
Thank you for the tips. It's a 200-gallon aluminium tank. Removal is not easy. Access is very limited. So I have to cut a big hole on top to clean it in the next coming few days. I guess (90% sure) the leaking is on the bottom somewhere have a small hole. It's about a few little leakages every season. Will try cleaning and pouring resin to the bottom first. Then try two small tanks if that failed.
 
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If the pin hole is not in a corner, why not drill a hole in it & place a bolt through resultant hole, with neoprene ( Check fuel safe) pads, backed up with Al washers & tighten up. Make sure that the neoprene is tight round the bolt. Also, the hole in the washer is oversize so it squeezes some of the rubber out against the bolt & the hole, to form the seal.
Of course the pin hole may be the result of rubbing such as where it sits on a bearer so that will not work. In any event any repair will be short lived if friction with bearing surfaces really is the issue. Other causes could be electrolitic action with another metal & that needs to be investigated.
 
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@Daydream believer Great idea! I will try if the hole position allows.

@jrudge Yes, cleaning is the most difficult part. I always try to avoid fixing it just because cleaning is a nightmare. But it's time to give it a try anyway.

@KevinV I have read that thread. But mine is a 28 years old boat. No warranty cover.
 
During all my leaky tank investigations, a resin system was suggested...and details of the company and product were given to me...I will search but I don’t know if I wrote it down...perhaps someone could search my thread in case I wrote about it...in the end it was (correctly) decided not to go ahead...the pin hole could be an isolated pin hole or the symptom of a completely corroded plate...in my case there turned out to be multiple holes when I assumed it to be only one...and while all my painstakingly meticulous investigations convinced me that the hole was in one place...it turned out to be in a completely different area. Leaks in any kind of storage or plumbing are notoriously difficult to identify unless you can actually see it.
I will see what I can dig up...but don’t hold your breath ?
 
Lucas Gan said:
I am going to pour a thick layer of resin into one of my diesel fuel tank bottoms to stop the annoying slow leaking. Do you know which resin should I use? Let me know.
Many thanks!
Click to expand...
From WEST SYSTEM:

When bonding to aluminium, you'll need to degrease it first as above. Then – if intending to use WEST SYSTEM 105 Epoxy Resin® mixed with 205 Fast Hardener® – you must chemically etch the surface with an etching compound or sulphuric acid/sodium dichromate solution. This primes the surface for adhesion to your epoxy.
 
The honest answer which none of us ever want to hear is replace it. Even Boubas one was smaller than the original.

There have been threads in the past where a number of ideas have been floated but none work.

Liquid epoxy is cheap of eBay etc. so if you can get it clean enough and you pour in an inch of it it will either work or not. If not you are down £100 ish, if not then if comes out.

If it works you might want to remove this thread as it admits to a significant bodge !
 
There is another way..all depends on how much room and how clean you can make it...but see if a welder a) wants to work on a fuel tank...b) will they/can they do it in situ
 
@Lucas Gan can you advise please what type / size of boat this is - and ideally post some photos showing the location of this fuel tank?

I note that it is aluminium, and that it is now 28 years old - there is a good possibility that apart from the current leak, there are many more potential leaks waiting in the offing, all ready to kick in and make life miserable for you, especially if there is corrosion occurring on the bottom of the tank.

What is the tank resting on? I hope that there is no possibility of it ever sitting in a puddle of water.

You had said :
"So I have to cut a big hole on top to clean it in the next coming few days. I guess (90% sure) the leaking is on the bottom somewhere have a small hole. It's about a few little leakages every season. "

Once you cut your 'big hole' in the top, how are you planning on covering up the hole again?
As @westernman has pointed out, welding the panel back in to the cut out is not a very good idea, especially as there is poor access to the tank already.

Re your 'few leakages every season', have you simply ignored these in the past, or did you try any remedies to fix them - and if so, were they successful?
 
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@Bajansailor The boat is an American-made [content removed]. LOA 42ft after cabin flybridge. The leaking starboard tank is under the after-cabin bathroom and wardrobe. Luckily all is dry. No water can be found down there. The top and side of the tank look in excellent condition. See the attached pictures for the layout. Item 20 is the leaking tank.

The cutting big hole on top can be covered by a bigger piece of new aluminium panel and become the inspection hatch if the tank is fixed.

I simply ignore the leakage in the past few years. I just simply put a few oil absorbent pads to the dripping outlet hole from the tank holding area then replace the pads every few months. Never try to repair it as I know there will be a pain to fixing or replacing a fuel tank. It is just that I recently replaced all fuel injectors, fuel hoses, valves and fitting. Only the fuel tank hasn't been touched yet, so I think it's time to try the tank fixing now.
 
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I can recommend the POR15 product, although this was on an old car fuel tank and it is still working well without any degradation after 7+years. However, you must follow the process carefully (see kit) and it is really designed with the tank removed so that you can rotate the tank at set intervals to completely seal. I did checked with the vendor and it will work with Aluminium, but whether it is cost effective due to the amount you need for a larger tank is something to consider. If you really sure your tank is leaking at the base, I suppose you could just apply to the base only, but you still need to degrease & etch (part of the kit) before applying the sealer.

https://www.frost.co.uk/por15-basic-big-fuel-car-tank-repair-sealer-kit/
 
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