Thread: Old Gavanised Raint water tank

hi all,

Was wondering i got a fairly large galvanised water tank that is quite rusted along some cracks that ar eupto 20cm long and was thinking is it better to fix it or to just scrap it.

and if the answer is to fix it how would you fix it?

They can be fixed - mostly by patching from the inside. You can use rolled corro metal or bitumenised aluminium (in conjunction with rivets and silicon) or the old school method was cement mortar with a bit of Bondcrete in it.

Question is whether you could be arsed. Personally, no. But then I just converted ours to a very resplendent chook house...because it was too good to scrap.

Mine have been converted into wicking beds to save water that way. Basically cut into three rings, plastic line the base up at least 30cm, insert some ag drainage pipe and top up with fat sand or gravel to height of plastic. Add soil on top, plant veges and mulch. Add water to the sand reservoir till it leaks out the bottom (if you want to be scientific you can insert a pipe at that level so you can see water coming out) and water from the top down once. After that, just add water from the bottom. Easy, stylish and effective, as well as very water economical.

You will probably go through two grinder discs to cut it up though, as they are pretty heavy gal metal.

I am told you can fix them using concrete. Supposedly you don't have to empty the water out or do any cutting, just pour the dry concrete mix into the appropriate place. Insert a piece of downpipe through the inlet strainer to direct it to the correct spot.

Haven't tried it. I've got a leaking plastic tank (it leaked and I got a new one under warranty and kept the old leaking one) that I've tried to fix. Unfortunately it leaked at a point that is a mechanical stress point (it is a slimline tank) so it needs to be reinforced with a bolt (= hole) and then waterproofed as well. The fix worked for about 2 years then started to leak. I have since put two round 2500 litre plastic tanks nearby to hold the water and I pump it from the leaking tank when the level rises above the leak (about 30cm off the ground). Due to the roof level and space available the slimline tank is necessary. I might just replace it with a sump pump as the new tanks are too high to be gravity fed from the garage roof and/or I could feed the new tanks from the house roof which is high enough. If I just replaced the tank with another slimline, it'd cost about $1000 to get a 1000 litre one to replace it (you can buy a 5000 litre round tank for that price). If I use a sump pump, I'd have to have a float switch to turn it off when the destination tank was full. Also the issue of the noise from a pump (I already have two pumps - one is bloody noisy and the other is very quiet, and I don't seem to be able to find noise specs for sump pumps). If I just hook the new tanks up to the house roof instead of the garage roof, I'd lose 50 sqm of metal roof which is much better for collecting small showers of rain than the lichen-covered tile roof on the house (plus the house has so many downpipes that I wouldn't be feeding 50 sqm of house roof into the tanks). But I digress...

I have considered using the concrete method to fix the plastic tank - I suppose I have nothing to lose. I wonder what happens about the differing expansion rates of concrete and plastic (or steel for that matter).

You might want to price a new tank before you try and fix it. They are pretty cheap these days.