I need to resurface a 25yr old pond in my backyard. It was constructed with bricks and mortar for the shape and then coated with what I think to be plaster. The plaster has developed many cracks and bare spots over the years and it needs another coat.
How should I prep the surface before replastering? The surface is very rough. Do I need to chip off as much plaster as possible? or should I use a bonding adhesive instead?
The pond is small, about the size of a large bathtub 8x3x2. It has a 6in lip around the outside which poses a problem for the plastering. I can't do an underwater cure because the lip is not underwater. Would I need to get concrete fortifier to mix in with the plaster so I can air cure it instead?
It appears that they used some kind of metal sheeting around the lip of the pond as well. I'm guessing it was to give it a flat even surface. The problem is that the plaster has revealed some of this steel and it has now rusted somewhat. Should I remove all rust and plaster over it?
you can see in the last picture where i chipped the exposed plaster off and the stuff underneath is bright white. The red color in that is just part of a brick i chipped.