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Corrosion In Water Tank

2002

One of our drinking water tank has corroded. Pl tell me what is the mechanism of water corrosion and what coating should I use to prevent it.

Tank deals with drinking water and is in service since last 7 years. Water has corroded the inside of the tank. We would like to apply the coating from Inside.

size: elliptical tank1890 X 1210 X 4060 cub. mm Mild steel tank

Prashant Kumar, Technologist
- Jamshedpur, Jharnkand, India

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Rubber, plastic or glass should be used as a liner for mild steel.

  
Tom Pullizzi
Falls Township, Pennsylvania
2002

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2002

Hi Prashant,

I didn't reply before as I had hoped that a 'specialist' in paints would have already contacted you.

From a plastics viewpoint, I'd suggest you use either an epoxy (expensive and somewhat more difficult to apply than polyesters) or check with a local supplier of fibreglass resins for a resin that, when properly cured, will not impart any odour problems.

Whatever you do, you MUST have proper breathing equipment! These resins generate bad fumes in an enclosed space!
1. Sandblast inner surface clean
2. Apply the appropriate polyester or vinylester resin BUT simultaneously use at least one layer of fibreglass mat in order to get some strength to this inner coating as you sure don't want a delamination to occur.

Your 'local' supplier maybe/should be able to offer more advice than mine... check with them, OK?

Freeman Newton [deceased]
(It is our sad duty to advise that Freeman passed away
April 21, 2012. R.I.P. old friend).

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The most economical method of repair would be to hang a membrane liner in the tank completely eliminating the possibility of further corrosion. For drinking water PVC vinyl is fine. There is a liner for most liquids even diesel fuel. Surface preparation is minimal however connections need to be sealed to the liner. Off the shelf fittings are available. Good luck.

Regards,

Warwick Spiller
- Gold Coast, Queenland, Australia
2003