Stainless Water Tank Repair?

Has anyone here had experience with repairing a stainless steel water tank?

Ive read what Casey and Calder say--SS is not the best choice. However, the original on my Alajuela 33 lasted decades, and if a properly welded repair will do likewise, why make perfect the enemy of the good?

I can find poly tanks to use instead, but in spite of their several advantages, I'll carry a lot less water and retrofitting to hold the new tanks in place will be a fairly big job. The stainless tank was made to fit the boat.

Has anyone else done it? How has it worked?

Thanks for any opinions.

John V.

[JeanneP]

We had two stainless steel water tanks in our Jeanneau Sun Fizz. Each at one time or another had pinhole leaks develop, possibly where the interior baffles were spot-welded in place. Both times we made a "temporary" repair using epoxy. Those "temporary" repairs never failed and to my knowledge the tanks and the repairs are still good 15 years later. But, they were very small leaks.

FWIW.

[Gallivanters]

I'm certainly no expert, but...

Our last old boat developed leaks in both the water & fuel tanks. They were aluminum. Luckily, they were both fairly easy to remove and carry off the boat for repairs. We were in Guam.

Our new old boat recently developed a leak in the fuel tank while we were awaiting transit in Panama. This one's stainless steel and too big to get through the companionway.. and the clock was ticking! So we repaired it inside the saloon!

In each case, we repaired the tanks by scribing a straight line around the lower perimeter of the tank, just above the corroded areas. Then cut along the line and simply had a professional weld in a new bottom plate.

The repairs never cost more than $200 USD because I did most of the work myself. We lost a few gallons' capacity... but the tanks slipped right back into place and with minimal "down time".

Metal tanks always seem to develop problems at the lowest regions where they're exposed to bilge water. Add a few stray volts and problems will quickly arise. So be sure to bond the tank to the vessel's ground network or to the engine block to minimize corrosion and clean the accumulated bio-sludge from the tank regularly.

Again - I'm no expert... but I found this to be the most cost effective and simplest method to repair and maintain my metal tanks.

I considered Jeanne's epoxy repair but I couldn't reach the problem areas due to the internal tank baffles.

Good luck - A friend in St Thomas just spent over $4000 just to have a new tank built!

To Life!

Kirk

[Calliste]

Hi John, the ss water tank on Calliste started leaking at the welds on the bottom.

I was told that using chlorine in the water to purify it , caused the leaks to develop at the welds.

My ss tank is removable but troublesome to do,,,,,,, so while in Oz , I had a new tank made from pvc plastic, and am happy with that.

My thinking was that if I had the leaky welded spots re-welded, it wouldn't be long before another place would start to leak.

I even considered putting a bladder inside the tanks, but cleaning that out seemed problemmatic , and difficult, for me to do .

To quote Brion Toss the rigger ,,, "Always try to build in a reserve of neglect" , and I try to do that on each repair or upgrade.

I have had heaps of problems with the SS original equipment onboard, mainly because of corrosion , so now I welcome the oportunity to replace the SS with bronze or plastic, when I can .

If you do decide to re-weld , think about using an "enrichening" filler rod such as # 625 , Inconel , which when welding, does not depleate the base metal of chrome and nickle around the weld joints.

http://www.burnsstainless.com/TechArticles...el_article.html

Douglas , S/V Calliste , Singapore

[/quote]

Jeanne, Kirk, Douglas--

Sorry to be so late in thanking you for your replies. I've learned that my tank is made of a grade of steel (304L) that doesn't lend itself well to welding as would 316 or better.

The inconel article was enlightening, though, Douglas, as it seems to offer a solution to the damage that ordinary welding does to the stainless. I will explore it further.

But otherwise it looks as though fixing the old tank may be setting myself up for more problems. So, I'm back to looking at rotomolded poly in a combination of 2 or 3 tank that will fill the space best.

Thanks again.

John

[Micah]

Originally Posted by JohnV

Jeanne, Kirk, Douglas--

Sorry to be so late in thanking you for your replies. I've learned that my tank is made of a grade of steel (304L) that doesn't lend itself well to welding as would 316 or better.

The inconel article was enlightening, though, Douglas, as it seems to offer a solution to the damage that ordinary welding does to the stainless. I will explore it further.

But otherwise it looks as though fixing the old tank may be setting myself up for more problems. So, I'm back to looking at rotomolded poly in a combination of 2 or 3 tank that will fill the space best.

Thanks again.

John

Hi John, I hope I am not to late to comment. 304L should be good for water tanks but for the reaction to chlorine. The L denotes a higher grade of low carbon stainless to minimize weld corrosion caused by carbon migration when melted during welding. Even though I have all the tools to weld stainless, on my boats bad tank welds I decided to clean and then fillet all the corners with a high density epoxy mix and then paint the the interior with food safe epoxy. I had to cut new access holes which the tanks should have had to begin with. This seems to have been a "good" repair and saved me from having to rip out the interior of my boat.

Micah, S/V Audacious, Moss Landing Ca

MIcah--

Just saw your post. Thanks for the idea.

I'm not an expert on stainless, but it appears from what I've read that 316L or better would make corrosion around the weld less likely than with 304L

I hadn't considered epoxying the inside of the stainless tank. How much confidence do you have in the bond between the epoxy and the steel? I'd wonder if sooner or later, differential expansion/contraction, maybe aided by some oil-canning in the stainless, may lead to seperation of the epoxy from the substrate, and eventually to breaks in the unsupported epoxy. I'm pessimistic by nature and you may well know otherwise. Where did you get the epoxy you used? Are there good sources online of technical info about the stuff?

John

[Micah]

Originally Posted by JohnV

MIcah--

Just saw your post. Thanks for the idea.

I'm not an expert on stainless, but it appears from what I've read that 316L or better would make corrosion around the weld less likely than with 304L

I hadn't considered epoxying the inside of the stainless tank. How much confidence do you have in the bond between the epoxy and the steel? I'd wonder if sooner or later, differential expansion/contraction, maybe aided by some oil-canning in the stainless, may lead to seperation of the epoxy from the substrate, and eventually to breaks in the unsupported epoxy. I'm pessimistic by nature and you may well know otherwise. Where did you get the epoxy you used? Are there good sources online of technical info about the stuff?

John

Hi John, Yes 316 has some molybdenum in it and is more corrosion resistant in salt water crevice corrosion so it may also be better than 304 L for the chlorine caused corrosion. I would be surprised if your fresh water tanks had more than slight surface corrosion away from the welds. Sanding and covering the welds with a 1/2" radius fillet of thickened West System Epoxy will cover the welds and should not be affected by oil canning or expansion and contraction issues. I use several different fillers for this use I probably used colloidal silica to increase the anti sagging property's, microfibers and high density fillers for strength in the mix. I then painted the interior with Ameron epoxy paint, filled my tanks for a few days twice to rinse. I also use a carbon filter. This filler mix is thickened and is very tough and sticks to metal exceptionaly well. Something like a tongue depressor would work as a fillet tool. This fix was about a tenth of the time and money compared to riping out the interior of my boat if it fails at some point in the distant future I am no worse off than before so I have been very happy with the tanks for the last couple years. Micah

[MMNETSEA]

Originally Posted by Micah

I use several different fillers for this use I probably used colloidal silica to increase the anti sagging property's, microfibers and high density fillers for strength in the mix. I then painted the interior with Ameron epoxy paint, filled my tanks for a few days twice to rinse. I also use a carbon filter. This filler mix is thickened and is very tough and sticks to metal exceptionaly well. Something like a tongue depressor would work as a fillet tool. This fix was about a tenth of the time and money compared to riping out the interior of my boat if it fails at some point in the distant future I am no worse off than before so I have been very happy with the tanks for the last couple years. Micah

Hi Micah,

Thanks for good info !!

Please clarify high lighted section : Carbon filter or filler? Which filler mix ?

[Micah]

Originally Posted by MMNETSEA

Hi Micah,

Thanks for good info !!

Please clarify high lighted section : Carbon filter or filler? Which filler mix ?

Hi, If you are worried about any paint residual a carbon water filter will remove it. The filler mix is like an off the cuff food recipe a little of this and that depending on the use there is no exact right mix and with the west system it is not critical. Read the filler product descriptions and West's info to get the feel for what will work in each different application, for a simple fillet it is not critical. good luck, Micah

[steveswain]

I bought a yacht which the surveyor said had a leaking water tank (SS) the previous owner said he had "just had a leaking pipe". When I filled it and received plenty of fresh water in the bilge I deduced that the surveyor was correct. I removed the tank and took it to a ss fabricator who pressurised it and it leaked like a proverbial sieve. He said it was electrolosis as it did not have a gound wire connection to the battery. He made me a new identical one (with a ground wire connection). He also told me that it was quite normal and I was lucky that mine had lasted 25 years, maybe Danish s steel is good? Anyway usually the problem it seems is that and if it is it will doubtless not be repairable.

Sorry John, Steve S