Water Tank Leak

[Tspringer]

The ongoing big refit has hit a big bump in the road....

Tonight I was snooping around the rear of the port main water tank, stainless steel and original to the boat (1981) and I was working a small brass wire brush against the bottom rear edge where the was some obvious rust along the welded seam. I go back looking at it again a few minutes later and there is a drop of water on the hull. So I get my mirror and watch closely, sure enough over about 1-2 minutes in one particular spot a tiny drop wells up and drops off onto the mirror. A leak, no doubt about it. Its leaking about a single drop every 1-2 minutes.

What to do?

Getting this tank out would be a huge mess. Tons of woodwork would have to be removed and I do not think the tank would go through the companionway in one piece. I would guess that replacing the tank would cost HUGE money and take months to get done. We are pushing hard on this refit to leave the dock and go cruising by mid October at the latest.

What other solutions are there? Can I epoxy some glass cloth to the bottom of the tank in this area? How about underwater epoxy putty?

ANY ideas are welcome...


Terry

[onestepcsy37]

i had a small leak in a 75 gallon fiberglass water tank that i could not find. i bought a product called 'gluvit' in a marine supply store. it's some kind of polyester resin that's supposedly finds it's way into cracks and seals them. i 'painted' the interior of the water tank with two coats of 'gluvit' and that ended the leak. i think i bought the quart size can. if you google on 'gluvit' you will find out more about it than i know.

my tank does have a very large access port in the top of the tank which allowed me to get my arm down in there and paint the gluvit all around the interior.

i don't know if this will work on stainless water tanks but maybe the gluvit website will be more specific....

[James S]

Yeh...thats a tough one...Can you get to the leak well enough to clean the metal on the out side and get it dry?
If so you can probably get away with some sort of surface repair with a spot of 5200 or the like...not sure what kind of smell or hazard that would create....if you cant get it dry then something like MarineTex may work.
Do you have clean-outs? can you get to the inside where the leak is?
Can you cut an opening big enough to stuff a bladder in there?
You can expect to find more of these pin holes as the time passes.

[David M]

For now I would put a patch of epoxy filler over the outside. If it has an access port then put a coat of epoxy on the inside. If it starts leaking again in a short period of time then you have a big decision to make

[Zednotzee]

There are several companies who, given the specifications, will build a custom plastic tank for a decent price- certainly cheaper than stainless, & no more corrosion worries. Plastic Tank Custom Fabrication Poly Water Storage Tanks - BARR Plastics
However, I have no solution for the removal conundrum with your existing tank.

[Dockhead]

For God's sake, a drop every one or two minutes. A standard drop of water is 1/20 cc. So in one hour -- 3 cc. A liter would take 333 hours, or two weeks.

Plug it with epoxy and forget about it.

[David M]

If your tank has no baffles then you may be able to put a collapsible liner in there. This will save you having to remove it or having to patch it.

[stevensc]

You might try draining the tank, dry out the leaking spot with a heat gun or hair drier and apply something like Splash Zone or JB Weld, press it into the crevice. If you can get at the inside apply there otherwise to the exterior spot where the leak is. Leaks may pop up elsewheres or maybe not. This might fix the problem for a few $$.
Good luck
Steve

[barnakiel]

There is a premix epoxy putty 'magic stick' you can squeeze in. It is sort of like the buble gum solution, except dries well wet.

b.

[Tspringer]

I am going to give this stuff a go:

Microseal, metal sealant, seal castings


I have emptied the tank and will be working to get it completely dry inside, then I am going to use a yard sprayer with metal wand to spray the stuff into the tank at the seams. I am also going to clean up the edges I can reach, treat them with ospho and then apply JB Weld.

That that all fails.... I may nuke it from orbit, the only way to be sure.



Terry

[motion30]

marine tex will work and last a long time or you can have somebody tig weld it in place

[GordMay]

Marine-Tex is NOT rated for potable water repairs.

➥ Marine Tex, epoxy resin, adhesives, silicone grease, engine treatment, cleaner, repair, bond, fill, seal, fiberglass, aluminum, plastics, Starboard, wood

[Wotname]

Assuming you can get it completely dry and very well cleaned (from the outside), I would try soldering it (standard 60/40 solder). You will need a decent heat source and assuming heat is not a problem for the surrounding materials.
316 SS will solder surprising well if you use phosphoric acid (rust convertor) as a flux.

[Tspringer]

The leak is on the bottom rear edge of the tank.... to solder it would require removing it and removing it would require huge de-construction of the salon.

The leak is tiny, the inside of the tank actually looks very good. After researching this more, my documentation on the boat shows this tank was replaced 10 years ago. This leak is clearly crevice corrosion on a weld seam. I believe that if I can properly seal this leak the tank will be fine. The Microseal seems the perfect solution.... we shall see. I am working now on getting the tank completely dry inside.


Terry

[James S]

Originally Posted by GordMay

Marine-Tex is NOT rated for potable water repairs.

➥ Marine Tex, epoxy resin, adhesives, silicone grease, engine treatment, cleaner, repair, bond, fill, seal, fiberglass, aluminum, plastics, Starboard, wood

its hard for me to imagine that a marinetex patch on the outside of a tank to close a hole or crack of the size described would have sufficient contact area with the water to be of any concern....having said that I'm no expert and probably did more than my share "partying" in my youth so ...it may be hard for me to tell if there would be any effect