Leaking Water Tank

[Chalker]

I have a stainless water tank that has developed another leak. 2 years ago I had the same problem and had a welding repair.
Has anyone found a liquid rubber or similar that I can coat the inside with? I have good access through an inspection hatch and the tank is out of the boat so easily manoeuvrable to spread a coating. I’ve repaired a porous dinghy the same way in the past.
Any ideas?

 

[Tranona]

You won't get anything to stick reliably to the surface of the tank. As it is out get the leak welded up and have all the other welds checked and redone if necessary.

 

[GregOddity]

I have a stainless water tank that has developed another leak. 2 years ago I had the same problem and had a welding repair.
Has anyone found a liquid rubber or similar that I can coat the inside with? I have good access through an inspection hatch and the tank is out of the boat so easily manoeuvrable to spread a coating. I’ve repaired a porous dinghy the same way in the past.
Any ideas?

I'm going to assume that the leak is on a weld. It's an easy repair provided you find a Stainless TIG welder new you. If the welder is not coded or never learned as a welder then he will do the mistake of just aplying rod to the area. When a leak develops ( Bad weld : inclusion of dust, Not enough traveling speed of arc, wrong angle for weld etc ) It is normaly to do with a weld that was not done to spec. Most are fabricators with no other schooling then seeing others do it. You need a welder for stainless. That leak needs to be grinded and rewelded not just retouched. 2 cm should more then do it. GL

 

[coopec]

This was the subject of a thread on YBW a few years back. Also you could do a YouTube search on "liquid rubber membrane leaks metal tanks". (Of course the membrane would have to be OK for potable water)

Clive

 

[peteK]

I have just repaired a leak in a stainless tank with JB weld epoxy,it will work just on the outside of the tank but to be sure do the inside as well,its only around £5.Make sure its clean and roughen the area before applying.

 

[Chris_Robb]

I have just repaired a leak in a stainless tank with JB weld epoxy,it will work just on the outside of the tank but to be sure do the inside as well,its only around £5.Make sure its clean and roughen the area before applying.

I repaired a tank 5 years ago - a long seam welded at an acute angle - where the leak was the result of pinholes the whole length of the seam.

I removed the tank - easy as it was under the saloon berth, abraided with sand paper all along the weld for 2 inches either side. I then used strips of glass tape which I epoxied on to the tank taking care to wet out properly, and once cured (still sticky) added a final coat to make sure there were no holidays.

The Epoxy was thickened slightly with microballoons which makes it stay in place and is less messy. I was in a Greek haulage yard and would not trust a welder without seeing his work beforehand to do it. At it turned out it was an easy DIY job and even if there was a good welder, I would not have used him. 5 years later there is no sign of a leak.

 

[lpdsn]

I'm going to assume that the leak is on a weld. It's an easy repair provided you find a Stainless TIG welder new you. If the welder is not coded or never learned as a welder then he will do the mistake of just aplying rod to the area. When a leak develops ( Bad weld : inclusion of dust, Not enough traveling speed of arc, wrong angle for weld etc ) It is normaly to do with a weld that was not done to spec. Most are fabricators with no other schooling then seeing others do it. You need a welder for stainless. That leak needs to be grinded and rewelded not just retouched. 2 cm should more then do it. GL

I'm told, by someone who inspects welds as a full time job, that the most common mistake welding stainless is using a rod made of the wrong material.

 

[GregOddity]

I'm told, by someone who inspects welds as a full time job, that the most common mistake welding stainless is using a rod made of the wrong material.

I'm trying to be political. But yeah. It is one of the most common mistakes I see. The other being using a very slow traveling speed and amperage in the hope of having more time to control the puddle of molten metal in the weld. This is completely wrong and the product of a lack of knowledge that the welder should have, basic really. The result ends up being a weld saturated with micro pores and cracks that will develop into something else with time (something else not being something you want) It’s easy to recognise by the Grey burned colour of the weld. Stainless welds should ALWAYS be shiny. Some hints of blue and beautiful shades of purple and you must be able to see like a fish scale effect on top of the weld if its thin plate. Thin plate actually requires a special coding. I have not met many TIG “welders “with it. I’m not saying that there are none, I’m just saying that most are all rounders in fabrication and do not have the proper qualifications or knowledge for TIG. But as everyone wants your money, off course they will try to patch something together for you if you’re paying. Just make sure you don’t buy a fuel tank from them.