Fixing Stainless Water Tank

[seashine]

PHP Code:

stainless water tank leak 


PHP Code:

fixing water tank leak 


We have a pinhole leak at the site of one of the baffle welds in our water tank">fresh water tank. The tank is about 30 years old and the water tastes fine, so we'd prefer to fix it rather than replace - if at all possible. Tank has been removed so we can thoroughly paint the floor it sits on, so we can "access all areas" as it were...
Reading elsewhere about fixing aluminium tanks it would appear the trick is to coarse sand, degrease then epoxy - and one person advises using a s/steel brush on the first coat of pox while it's wet to prevent any bloom, then immediately recoat. S/steel is a bit shinier than ancient alloy though...
I would tend to think that maybe a Dynel bandage might be the go too, wrapped around the whole tank as all the baffle welds are in line. The main reason for posting is to ask what everyone thinks about the relative inflexibility of epoxy coating relatively flexible s/steel (in spite of baffles etc, I'm sure the tank sides are likely to flex a bit in a seaway) - is this likely to be a problem? I don't want to have to deconstruct the tank again any time soon as it would mean disassembling the sofa next time round! Ahh the joys of awkward spaces - who needs to do yoga when you own a boat...

[Artif]

Why not do a proper repair and weld it, then you can forget about it for another 30 years.

Epoxy patches will work but they are a last resort repair for in-situ tanks.

[seacap]

I just had my SS tank spring a leak after 22 years. I will be replacing them with plastic.

Something to think about... if you have one leak, you probably have other areas about to go.

[barnakiel]

Why not weld it?

b.

[peghall]

I know a lot of people who've had very good luck using JB Weld J-B Weld Company - J-B WELD Product Information including one houseboat owner who's even used it to patch so many leaks in an aluminum HOLDING tank that I've kidded him that he'll soon have a whole tank made of the stuff. All the patches are still holding after several years, so if it stops a leaky holding tank (not that I'd ever recommend using it on a holding tank!) it oughta stop a leak in a water tank.

I called the company...there's just one place to get it in OZ...a company called Brilliant Signs...she didn't say exactly where, but she did give an email address that she knows is good: matt@brilliantsigns.com.au and a phone # she THINKs is good: 61 3 9555 1522.

I'd give it try...you don't really have anything to lose.

[Mark Johnson]

I would attempt to silver solder it. (The spot has to be RED hot first). You can get a canister style "MAPP gas" torch from Lowes for pretty cheep. The epoxy bond with SS is poor, so a proper sanding prep under a Dynel bandage is making the walls thinner, and if the welds stand high, you will be making them thinner too. This might just be opening a can of worms. If the weld fails, you can get custom made SS tanks for less than you'ld think!

You might want to research this first, if you think that there may be more failures down the road...

Mark

[detav007]

JB Weld can be picked up at any auto repair shop. It's resistant to fuel and oil so water shouldn't be a problem.

[peghall]

Originally Posted by detav007

JB Weld can be picked up at any auto repair shop.

In the US, but not in Australia.

[detav007]

Well all I can say is that bites. How do you ozzies keep your heli coils in place? we can pick that up at any auto parts or repair place on every corner here. I guess you have trade off's for living in paradise.

[cabo_sailor]

Since you have the tank out, I'd vote with the others suggesting you find someone qualified to weld stainless. A couple of minutes and you'll be good for another 30 years.

Rich

[seashine]

Thanks for all the advice people, I'm taking the tank to my stainless welder tomorrow and will specifically ask him if he thinks it's a repair or replace job. Also thanks Mark for pointing out the issue of wall thinness after sanding: the reason we were thinking of Dynel/epoxy is that we'd seen a photo in CH of a tank that had been bandaged and lasted another 8 years. Hence the question about flexing.

BTW: I found JB Weld at Jaycar... a place often frequented by cruisers in search of busbars, tinned wire, heatshrink, solar panels etc etc Will get some in case the tinnie springs a leak when we're out on the reef: J-B Weld Epoxy - Jaycar Electronics

[Passage50]

Originally Posted by cabo_sailor

Since you have the tank out, I'd vote with the others suggesting you find someone qualified to weld stainless. A couple of minutes and you'll be good for another 30 years.

Rich

I found welding Stainless is no big deal. Do it all the time with my regular Welder which is just a little Miller. And I am just a hobby Welder. tThat said I would like to think welding would be much more durable and since you have the Tank out the way to go.

[Mark Johnson]

Originally Posted by seashine

Thanks for all the advice people, I'm taking the tank to my stainless welder tomorrow and will specifically ask him if he thinks it's a repair or replace job. Also thanks Mark for pointing out the issue of wall thinness after sanding: the reason we were thinking of Dynel/epoxy is that we'd seen a photo in CH of a tank that had been bandaged and lasted another 8 years. Hence the question about flexing.

BTW: I found JB Weld at Jaycar... a place often frequented by cruisers in search of busbars, tinned wire, heatshrink, solar panels etc etc Will get some in case the tinnie springs a leak when we're out on the reef: J-B Weld Epoxy - Jaycar Electronics

Sounds like a good plan... BTW, If you ever DO decide to epoxy bond fabric to SS or for that matter, SS hardware to the boat, (= bedded in epoxy & fastened mechanically), here is how you prep the SS:

Solvent wash, (Acetone or MEK) the SS, then mask what you don't want scratched up on the SS. Now, fold a piece of new "wet/dry" 80 grit sandpaper and sand the hell out of the SS to be bonded to, but use CATALIZED EPOXY rather than water as the lubricant. I use a HARD epoxy like WEST brand for this.

Next, you immediately apply the fabric to the SS, wet it out, and squeegee lean, then clean the excess. (let cure & apply several top coats, 45 min apart). The bond is perhaps half as good as if applied to fiberglass or wood.

For epoxy bedding SMALL padeyes & such (2"-3" is fine), that will never break, wear out, or need replacement, you do the above treatment to the SS base and bed in epoxy, thickened in silica & High D fillers. Screw down fasteners and let cure.

I normally bed through bolted stuff in caulk, if it is possible & on a flat surface. The epoxy bedding is particularly usefull if you need to put a pad eye over a THICK solid wood or solid glass spot, where you can't put a nut & washer. (I have a few of these on my boat)

To fasten these, (1/4 or 5/16)... you use flat head machine screws 3"-4" long. You drill the holes in the boat (1/16" too small), tap threads with the correct tap, and epoxy saturate the inside threads in the hole. (make a dry run first and screw it down to be sure the threads are deep enough)

NOW, push all excess resin out of the hole with the butt of a drill bit or something, quickly do the above prep to the base of the hardware, put thickened resin on the machine screws and under the heads, and screw it down snug but not OVERLY tight. Solvent wash the excess...

Mounted this way, a good beefy pad eye will be stronger that the tensile strength of the screw's heads, and last the life of the boat! My last boat had 1/2" U bolts with their 6" threaded legs epoxy bonded into into large holes in the glassed wooden crossbeams. (= no nuts or washers, just filled with resin).
These were my aft chainplates, and I could easily lift the boat by them!

Good luck on the repair, M.

[DogOnBoat]

We had the same problem. Our friend welded it for us, and now there IS no problem.

Me Voy: Fuel Tank and Fresh Water Reservoir Installed

[LJH]

I am not familiar with welding stainless steel. My water tanks are 28 years old and are seeping at the spot welds where the baffles are tabbed to the tank wall as well as along some of the welded seams. I am in a location without a marine industry and dealing with workers in a language a second language for both of us. They did some re-welding along the seams and the tank is leaking around their repairs, perhaps at an even faster rate than it was before.

The company here now says that my tanks are too old to fix! They say will have to fabricate new tanks for me. From the look of the tank that I managed to remove, it had not been previously repaired. They re-welded the area where the seam was leaking and not the whole length of the seam.

I have some questions.

• Is this true about stainless steel? Will it become to thin to work with? Is it possible that the re-welding that leaked was poor workmanship or material failure?
• Is there a specific method or equipment that should be used to make this sort of repair?
• If I have to have a tank fabricated, what thickness steel should a 45 gal/200 l tank be? The shop here says 2mm!
  For those who have used JB - weld. Is safe for drinking water tanks? do you apply to the outside or inside?

Any advice or pointers will be greatly appreciated.