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cilkorules
27th Aug 2007, 05:26 PM
How do i weld a galvanised water tank(to repair)
TO repair a split in the base of the tank how do i go about welding it back so it doesn't leak...
It's made of galvanised steel, what welder to i use to repair it and what tools should i acquire to do the job,

The tank is drained and ready for me to repair it i just not sure what is the best way...

thanks hope i can get some good information soon.

DJ’s Timber
27th Aug 2007, 05:53 PM
How thick is the steel and are you repairing from the inside or the outside?

Is the split from rust or a seam that has split open?

Stringy
27th Aug 2007, 06:12 PM
Need a picture!

If it is a gal tank, then it may have been built with lead solder, so fix by cleaning up and soldering.

If colorbond then I have no idea but there must be some type of silastic product that can be used in drinking water.

If rusted out and falling to bits, then line with rabbit netting and render (on the inside), done a few biggies like this, but you need to stop the bulls fighting near the tank as the render breaks with heavy impacts:no:.

Coldamus
27th Aug 2007, 06:13 PM
With a welder you are likely to blow holes in it. It would be better to solder it. The heat will be conducted away quite quickly, so you'll need a soldering iron with plenty of thermal mass (i.e. big and heavy) and an lpg, butane or petrol blowtorch. No chance of doing it with an electric iron. The surface will need to be clean and I suggest a flux like Bakers Soldering Fluid used with a bar of solder rather than flux-cored soldering wire. "Bakers" is corrosive though, so should be washed off thoroughly afterwards.

If it has cracked because it has rusted through from the inside, then welding is definitely out. You might still be able to salvage it by soldering a strip of galvanised plate over the affected area.

specialist
27th Aug 2007, 07:33 PM
If the hole is in the bottom, just clean well and seal using sikaflex, the grey one. This is what all the new tanks are sealed with, as lead solder isn't allowed in food grade water. It will also work on the side but you will have to paint it with something because the sun will eventually break it down.

robert

cilkorules
28th Aug 2007, 07:15 AM
If the hole is in the bottom, just clean well and seal using sikaflex, the grey one. This is what all the new tanks are sealed with, as lead solder isn't allowed in food grade water. It will also work on the side but you will have to paint it with something because the sun will eventually break it down.

robert

so if i use this sikaflex, to fix the small split in my water tank, will the pressure of the water in the tank still burst through do you think...
where do you think i can get some of this sikaflex ?
will i be able to get this from a local hardware store, is there a specific type of sikaflex to get...that will dry tougher and not break down.
painting over it wont affect the bonding to the galvanized steel?
how should the sikaflex be applied over the damaged section of the tank?
-smeared right over the split covering any future possible leakes
-or applying a few light layers waiting for each layer to dry before applying the next
-thus all the above probably (it should dry hard as conrete right)
will i need any tools to apply sikaflex?

specialist
28th Aug 2007, 08:46 PM
I would just clean the affected area with a wire brush to rough the metal and remove any rust and other impurities, then smear the sikaflex over it from the inside if possible and the outside about 3 to 4 mm thick. One layer is enough. If you really want the repair to be good and the split is long, then sandwich the the sikaflex with another piece of tin the same as the tank. Then just smear some around the edges to cover up any open steel.

It will not go as hard as concrete, it'll stay a little flexible, you can paint it, and the tube said that it can be sanded, although I've never tried.

No special tools to apply, only your fingers and/or putty knife and some washing up detergent and perhaps a caulking gun might help. Dip your finger/knife in the detergent to smooth the finish, that way, it won't stick to every thing that you use.

Make sure that no detergent goes on the area to be fixed before the sikaflex goes on. :C Only use the detergent for smoothing the finish.

You should be able to buy it at any good hardware. I bought that tube at bunnings, can't remember how much though.

Any more question? Please ask

Robert