Repair of stainless steel water tank

[wsmurdoch]

I had a leak in the holding plate in the freezer. It is made of light gauge stainless. The leak was in a weld at the almost inaccessible bottom of the plate. I was not keen on breaking into the refrigeration gas to take the holding plate out, so this is what I did. I drained PG/water from the tank. I refilled it with a mixture of water and a good shot of red food dye, then I pressurized the holding plate with a tube and my mouth. Feeling along the leaking weld with a white paper towel, it was easy to find the leaking section. It was on the bottom where I could only touch the weld with the tips of my fingers, but I could not see it even with a mirror. I sucked out the red water and filled the holding plate three times with acetone to clean both the tank and the crack each time pressurizing the tank to force a good bit of acetone through the leak then syphoning out the remainder. I wiped the weld with a dry paper towel while the acetone was leaking out to clean the exterior surface of the weld. With everything acetone cleaned and dry of acetone, I mixed up the first little batch of JB Weld, put a dollop on my finger, and did my best to force it into the weld crack while sucking a vacuum on the empty holding plate hoping to pull a little of the epoxy into the crack. That was followed with two more finger applied coats of JB Weld.

So far, years later, it is still holding. Kollmann Marine Products Refrigeration System

[cburger]

I usedJB Water Weld suitable for potable water worked like a champ on my stainless tank, couple of bucks at tractor supply

[captlloyd]

Originally Posted by Jim Cate

Zee, I'm wondering why you say this about the welding? I'm not a pro welder, but have done a fair amount of s/s fabrication, and TIG is the method of choice IMO.

Jim

I am a professional welder and you are quite right. Actually either method will work if done by a competent welder.

[captlloyd]

Originally Posted by cburger

I usedJB Water Weld suitable for potable water worked like a champ on my stainless tank, couple of bucks at tractor supply

Yes. If you can locate the leak and access it with your finger you can fix it with JB. Get it as clean as possible.

[zeehag]

Originally Posted by Jim Cate

Zee, I'm wondering why you say this about the welding? I'm not a pro welder, but have done a fair amount of s/s fabrication, and TIG is the method of choice IMO.

Jim

jim--i may be getting the terms confused--but the spot welding did no good.. should have been continuous welding, not poco a poco. the spot welds opened other welds that then failed and continuous weld would not have done that, as the new drips are in different spots than the original ones.
is there something else i should do when i get them rewelded this time??
i could use the tips...

[captlloyd]

Originally Posted by zeehag

jim--i may be getting the terms confused--but the spot welding did no good.. should have been continuous welding, not poco a poco. the spot welds opened other welds that then failed and continuous weld would not have done that, as the new drips are in different spots than the original ones.
is there something else i should do when i get them rewelded this time??
i could use the tips...

Welding on one area should not affect another area unless someone did a really bad job of welding in the first place. And yes, the leak area to be repaired would normally have welds extending at least an one or two inches past the leak area. Continuous welds, not spots. You could pull the tank and glass cloth and epoxie all the seams on your tank to cure the problem. That is what I would do.

[fabricator-ken]

The water Cooling is only for the torch head so you can hold it. It has know effect what so ever on the weld. I am a welder and have manufactured many ss tanks. I would only use Tig. Patex liquid steel will fix small holes also Loctite super wick in is very good to fix weld porosity.

Sent from my C6903 using Cruisers Sailing Forum mobile app

[noblewarrior]

I had a similiar problem with my 30 year old steel tank. I cut open access hole to each bay in the top of the tank. I identified a leaky weld on one of the baffle welds on the bottom, then ground down to get access and cleaned as above posts. I the applied this stuff https://sugru.com/ . that was 1 year ago still holding, €9 for a pack of 3 sachets, used two on this job.
i have also used this to repair a broken outboard cover 3 years ago, still holding.

[s/v michaela]

I also am a welder and agree that tig is by far the method of choice on a tank.....but that being said ...look up belzona. It is the method of choice when a hot work (welding) permit can't be had on offshore oil rigs. It is pricey... but fantastic stuff that can be used underwater or over an oily substrate. You won't find a better or more versatile compound. The navy also uses it on ships......

[Rorzech]

If you have an inspection hole big enough to get your arm and a snake camera ($120)both in at the same time , you could use the great clear nontoxic polyurethane like Teroson MS 934 . It's made in Germany and it's relatively expensive.($30 a tube) I've used it before and was very impressed. If you can locate the leaky seam , I'd spread this stuff on the seam with a putty knife. This material says it will stick to anything dirty or not and no primer required. From what i remember the non toxicity was a big deal for this stuff . You should look it up on the internet and see if it has the right properties that you're looking for. I was so impressed with it , I bought 6 cases of it. I think this stuff would patch your hole permanently .

[tkeithlu]

Back to the original topic. I had a leak on the bottom back seam of our 140 gallon stainless steel water tank that I could neither see nor exactly locate - a paper towel swiped along it would come up wet. I took a piece of aluminum angle almost as long as the seam, filled the inside of the angle with a generous bead of 5200, slid it into the space and pressed it against the seam. It worked. Been over a year now, and I'm not inclined to revisit it by wrestling that tank out of place and then what? Bringing a welder into the engine room and attempting a repair of a tank that is not leaking? Way down my priority list.

[captmikecoin]

Some good ideas here worth trying. Thank you everyone.
Mike

[boatnerd]

It may be a longshot but you might look into this product. A cheap fix@$70/gallon. .I used it to seal a steel diesel tank pinhole leak. Has held up a couple years now. A friend recommended it after sealing his ss watertank. It's a very thin penetrating liquid which evaporates very quickly.

NOTE: Read the data safety sheet. Extremely toxic vapors! Use respirator/gloves/eyeprotection.

http://microleak.com