Vactan over bituminous paint

[Colin Brendan]

Was thinking of using vactan to treat rust in water tank and then some bituminous over the top.

 

Problem is there's still some of the old bituminous on there. Will vactan stick to the bituminous already on there or will it flake off along with new bituminous coats?

[Grace and Favour]

I've not had the (dubious) pleasure of paintin the interior of a water tank.

 

However, I suspect that the vactan will not adhere to bituminous coatings - - I'd clean the whole lot off with a flap disc (or two) - and then apply your chosen coatings. (Can one use Vactan inside a tank, or should one use a simpler treatment such as phosphoric acid? (which is safe for consumption in dilute quantities))

[MikeV]

I'd try and just use Vactan on the rust. It shouldn't be hard to keep the majority of it off the bitumen.

 

The first time I did my tank I had to de-rust the whole tank (horrible job!) and I then coated it with 3 coats of Vactan and 3 coats of bitumen with a small roller. When it next needed doing after 2 years there were only a few patches that needed taking back to the steel and were treated with Vactan. I then rollered the whole tank with two more coats of bitumen.

 

To make the application of bitumen easier keep the tin hot. I stand it in a bucket of boiling water for at least an hour and regularly top up with more boiling water during the application. It's important that the tank is completely dry as well. I put a small electric fan heater in the tank for a while which probably also softened the existing bitumen a little which should improve the adhesion of the next coat.

[saltysplash]

Vactan is safe for water tanks, Scrape off the flaky rust with a wire brush and vactan over the metal, if the old bituminous isnt flaky then no need to remove it or vactan it, just repaint over it.

 

You only need to vactan the rust/metal

[Colin Brendan]

Thanks all. I'll try and keep it off the bitumen - what a horrible job, especially when you have to wrap yourself round a redundant bow thruster tube to get to the far end.

[Murflynn]

That's a strange arrangement unless the water tank has been modified. Obviously an electric bow thruster motor cannot be under water.