I have used product from www.epoxyproducts.com and they have under water potable epoxies, also I have seen some products at this site but have not used any www.concretenetwork.com/...sealing/sealers-underwater-exposure.html

I have never tried repair when it's not dry though, might want to ask before you buy one of their epoxies.

Good luck!

There is a product out of Canada called "Liquid Rubber" that could be used, but this would most likely require a commercial application- it is usually sprayed on. I believe there are a number of similar products on the market as well.

Not long ago, I salvaged a failing concrete tank by lining it with fiberglass- this worked well, and the lining was designed to be a stand-alone tank, so when the concrete finally gives way completely, there will still be a tank. This may be a solution more appropriate for a do-it-yourself project, if you have any experience laying up fiberglass.

you need to buy a food grade epoxy to apply to it and it should be able to be applied by you, I have done so myself as well

From your description (iron and concrete) it seems that future leaks will be a problem unless the entire tank is sealed or lined. I'm not sure where you are located, but you might consider using a tank liner rated for potable water.

Something like these maybe?

http://www.wetearth.com.au/Tank-Liners

http://www.websweeper.com/liner/tank-liner/

Suggest searching locally for "potable water tank liner".
Good luck!

It would be helpful to know if the concrete portion or iron portion is leaking or if it is the interface that is creating the problem. If it is the concrete only then Xypex will likely cure it. If it is the iron portion or the interface then you may be forced to to not only empty but to clean it. There are some expanding grouts and epoxy sealers that will work underwater but they will not be easy to apply. Preparation is the key in almost any situation such as this so emptying and cleaning is likely the the only reasonable path to guarantee success

Good luck

Fiberglass. Fairly easy to apply, should last for years, be sure to tell your supplier that you are lining a potable water tank so that he gives you resins that will not poison you or your goldfish.

http://www.kryton.com/

Hi

A tank liner would seem a good solution to your problem. It'll fit inside your existing tank and will eliminate problems with future leaks.

ATL make liners and are based in the UK and the USA. WWW.ATLLTD.com

Put in a big sheet of EPDM as liner. It's not cheap, but it will work.
My personal view is that anything else is likely to be a waste of time and money, the weight and temperature changes will just open up the cracks.
Any form of patch will have edges and we all know what edges will do eventually.
My big Sis just drained and patched a garden pond, she didn't take my advice.
It took her ages cleaning and patching cracks. It looks fine, but still leaks like a seive. I refained from saying 'I told you so' cos she might hit me being my big Sis.
Del

Hello Del when you get a moment checkout the usefulness of this tech. Is best as an add mixture but we've experienced excellent result when applying to existing also.

I use EPDM too though not for potable water, it's wonderful roofing stuff and I hung it as temporary siding on a shed one winter; no claw marks.

bwire, that product is very similar to Xypex, which I have specified on many a potable water tanks and other concrete tanks. Stuff hasn't let me down once with zippo leaks! I'd recommend it to anyone that's going to build or rehab a concrete tank. However, I don't know how well it'd work with thin concrete overlays unless it's an admixture in shotcrete placed at least a minimum of 3 or 4 inches thick.

Have great day!

Hey Del, my 5 border Collies and my 1 Welsh Pembrooke Corgi want to meet your kitty someday....they luv kittykats!!!! LOL

A swimming pool liner will do the trick every time.

I've used countless bags of this white surface bonding cement that you can pick up at the local store. for under $20 ....no.. it's NOT $4-6 like concrete or mortar.

One of it's described uses is for lining cisterns.

It's a very forgiving product that will mix and flow nicely.

It's also fibered.

I have used it to seal more than one... or 100 leaks in concrete.

It's workable at lower temps, and ok in somewhat funky water.

I would pour the product into the bottom of the wet tank.

Mix with a 3-6" hand trowel until the lumps are gone.

Spread it liberally when it's about like thin peanut butter... or a little thicker.

..in my experience.. everywhere you spread this stuff.. it will seal up.

it will start to set like mortar, but can easily be mixed workable.

The nice thing with this stuff is you can achieve a good bond and seal whether it's translucent thin or several inches thick. (when used accordingly)

When it's dry, you can even carve the stuff.

.. I believe you can even use warm water with this to speed the set time, but I like the hour or so I get from it naturally.

The longer you work this stuff , or the thicker mix it.. the sooner it will set.

I don't know if this would be the answer for you, but it might get you 99% there.

I would think you could put it down on the bottom at an inch or so in thickness and never think about it again.

...I know a good caulk that work in freezing temps.. wet.. etc.. It's a little tough to work with, .. almost no working time, but the stickiest, moviest, forgiviest stuff I've used. I think it's simply called Ultimate caulk? But, for potable water? it might be loaded with radioactive carcinogens for all I know?

Hello brhaar,

First thing I must ask from you is additional information, because since no one has asked for it yet:

1). How large is the tank? Dimensions?

2). Can you gain access to the interior of the tank through a manway that's large enough?

3). How thick is the iron or steel shell?

4). Is the iron or steel shell welded or bolted together?

5). What is the extent of the corrosion of the iron or steel, and is it the sole source of the leakage?

6) Location and extreme yearly temps. (max and min.)?

and,

(7). Determine what type of metal it really is.....steel or iron? You need to know this if you plan on welding any patches on the tank. Ditto for selection of any coating or liners for proper adhesion.

If the corrosion is not too bad and is the source of the leakage, then you may be able to cut-out those bad sections with a torch, then sandblast the remaining sound metal around those prepped areas, then arc weld some new steel plate as a patch in each and every area of concern. Make sure you also sandblast the entire exterior and interios surfaces too in preparation of applying any and all coatings or liners. This will also act as a good visual check for any other corrosion areas that weren't found previously. Cheap insurance if you don't want to replace the water storage tank!!!!

For the interior of the iron or steel tank, I'd suggest that you sandblast the metal to remove any rust, then apply a polyurethane of two-part epoxy coating that is approved for use in contact with potable water. If fact, some coatings can be used on steel as well as concrete, thereby saving you the hassle of applying 2 different coatings. Check out either TNEMEC or Sherwin-Williams (Industrial Coatings) for starters. there are others coating manufacturers as well.

In conclusion, my suggestion for you is to stabilize the corrosion on the tank first before you apply any coatings or liners, otherwise future rust-through will make the steel or iron portion of your tank useless especially if it is tall and has a good-sized water column (ie, pressure) acting upon it.

I look forward to seeing the additional information I requested, then we can collectively put all our heads together and find you a economic and viable solution to your problem(s).

Have a great day!!!

Signed,

Da CaptMoosie

The permanent method of repairing corrugated iron tanks from my grandfather's time was to plaster the inside with a render made up of fine sand, portland cement and lime. Tanks done that way last for years with no leaks even when the metal of the original tank was rather poor.

I assisted a neighbour to plaster his tank once, adding some bondcrete assists in application and improves the seal further. It is labour intensive but durable.