Thread: Water tank: Steel treatment for rust

Emerclad is a water-based waterproofing paint that is used for roofs, box gutters, and that kind of stuff.

One of its other applications is drinking water tanks - when your corrugated steel tank starts to rust out you just paint a ****load on the inside- buy two colours and do alternating coats to ensure coverage.

Great stuff, but wear old clothes and don't use the good brushes.

Cheers
Simon

mmmm Emerclad...good stuff (a bit like "use Snibbo")

Start with a zinc coated (galvanised) steel...and there are various grades. The zinc coating near the welds will be destroyed during the welding so "cold gal" paint will need to be applied to the joints. Then apply Snibbo.

I reckon that the seperate lid plan is the best idea so that you can get to the welds on the inside and apply the Snibbo....swirling is random.

4Bee - I live at Balhannah on a vineyard. If I go down to town I always take Greenhill Road as I have a couple of sports cars and it is SUCH a good road, apart from the bloody sunday drivers on the weekends.

You'll easily recognise me in the 130 now, it is naked at the back except for a plank of wood with the brakes/indicators screwed onto it. I've also got a white Disco TDi, but that is fairly non-descript apart from the snorkel and lift.

Where are you and what do you drive?

Between Summertown & Piccadilly in the Piccadilly Valley.

Carrigada Green '95 Discovery & restored deep green 2A SWB soft top.

Yep, you won't be hard to miss with a build like that. Has the plank been approved by LRA?

Nice. Just down the road!

Be damn cold down there atm. We had -1 last night, and -2 a few nights ago, and I reckon you'd be colder over there. The wood stove is doing overtime this week.

Has been a tad parky. Someone who lived at Balhannah told me it's on record as one of the coldest places in the Hills so I am not surprised, especially the section from the pub towards the North.

We are up on the Mt. Bonython east slope, so not too bad.

Our heater hasn't been out for 4 weeks.

Spudboy, funny that you mentioned that painting would be an option for you.
I'm a screen printer by trade, and at work we just painted a Steaming chamber for "curing" prints, the short of that is that an expert came out from Wattyl I think, and he recomended a "plasticised/polymerised" two pack paint which is specifically made for coating water tanks.

This little number will withstand mild acids, temp up to 120 deg C, and is considered "food safe" after it's TWO week curing period....

From memory I think it was called PHENGUARD, it's a Primer and Finish coat, both in two pack.....and I will write down the details off the cans for you tomorrow.......
I hope this helps you....cheers.......

1. The steel tank will take many months to rust through even if you fill it with seawater.
2. Attaching a marine sacrificial anode to the bottom of it during construction would extend this to years, probably many years if you only fill it with fresh water. In either case you could expect to have somewhat rusty water.
3. The alternatives to completely solve the problem would be :-
a. As suggested, make the tank out of stainless or aluminium. Probably the best, but aluminium will corrode under some circumstances, and stainless will work harden and crack unless properly designed and built. The skill required is greater than with mild steel for either, although stainless is probably easier to weld (aluminium is a good conductor of heat and melts at a low temperature). Either material would add substantially to the cost unless you can scrounge materials. With aluminium you must not use brass or copper fittings.
b. Fabricate out of mild steel but design to be dip galvanised (requires openings on opposite ends, no traps for liquids - consult galvaniser) and have it hot dip galvanised. Probably a lot cheaper than you expect it to be, and will last a lifetime if you only put fresh water in it. Suitable for drinking water, as is stainless or aluminium.
3. Compromises:-
a. Build from mild steel but provide a lid that gives adequate access for painting and can be screwed down. Sandblast and epoxy paint with paint designed for water tanks.
b. Build from heavy gauge galvanised steel sheet, designed with edges outside as far as possible, rivet and seal seams with silicone rubber. Should be OK for drinking water, long lasting, but will need to be supported by a frame and straps.

In any tank you should provide baffles to stop the water sloshing round, a suitable filler and a separate high level vent. Think about the outlet position. In the position you are looking at, an outlet on both sides would provide convenience plus the ability to drain regardless of which way the ground slopes.
John