paint for aluminium water tanks

[tomJ]

I have integral water tanks, currently unpainted, there is some pitting which I intend to fill, then i want to paint them to prevent further problems, however i want a paint that will not taint the water,any ideas?
many thanks in advance
Tom

 

[Ships_Cat]

The best approach is to talk to a company specialising in industrial paint systems and which has a food grade epoxy paint approved for use in potable water tanks. I am not in the UK so cannot recommend anyone there (assuming that you are in the UK) but a google will turn up plenty.

In my experience, in a number of countries, the paint manufacturers are very helpful and will prepare a complete specification for you. One problem can be the minumum quantity the paint is produced in, but 4 litres should be possible.

While this is not so important for aluminium as it is for steel, normally the first place the paint starts failing in freshwater tanks is on sharp edges or things like weld splatter which has not been ground off the plate - the thinning of the paint as it runs off during drying due to surface tension makes those the likely failure points. I mention it because is sometimes not stated in the paint manufacturer's specification. It can also be difficult to access tanks for proper preparation if there is not a big hatch and little wriggle room inside for tools - however, this is not such an issue for aluminium as sanding of the aluminium only is usually all the specification will call for (steel should be blasted).

I would be very wary of informal advice from boat owners who made up their own specification.

Some epoxies will taint the water when freshly painted - it goes away but can be hurried by filling the tanks with a solution of around 5% weight for weight commercial sodium bicarbonate (which in many countries can be bought from swimming pool chemical suppliers if no chemical supplier handy to you) and leaving for a day then flushing.

John

 

[savageseadog]

Leighs paints Bolton or Manchester do nthis type of paint