Underwater curing coatings 1

[kevlar49]

Can anyone give me some leads regarding underwater curing coatings? My application: clarifier operating in waste water treatment of a refinery uses FeCl3 as a flocculent to remove solids and selenium from water to be sent out of the refinery. Some HCl is also added to maintain a pH of 6.3. The clarifier operates at ambient temperature, atmospheric pressure. It was originally built with a coating and zinc anodes. The anodes have reached the end of their useful life and the coating is failing around the splash zone where anodes can't protect anyway. We can clear the tank to allow us to clean and recoat, but we will only have about 3 days to coat a 3700sq ft surface (70ft diameter) with rake arms, and shroud.

 

[Goahead]

Which was the original coating? Why underwater curing? Clarifier base metal was not described: is it mild steel? By the time you recoat with a suitable epoxy system, coating will be cured in air.

http://www.welding-advisers.com/

 

[kevlar49]

I think it may have been a coal tar. Records are not that good. It is mild steel.

We may use up most of the 3 days trying to prepare the surface.

 

[rorschach]

Kevlar49, I believe the old phrase "never time to do it right but always time to do it over" may apply here.

 

[SMF1964]

The Nuclear industry has some experience with this type of coating application (I'm thinking spent fuel pool where draining to apply a coating system is like stealing Jobu's rum - "ees very, very bad."). You might try looking there.

And I agree with rorschach. Also, you're going to get the old adage "Good. Fast. Cheap. You get to pick only two." for this project.