Chalky and Powdery Plaster

[PolarNorth78]

Morning All,

I'm teaching myself how to plaster and my latest attempt produced this. It's a very powdery and chalky and can rub it off quite easily.

The undercoat and initial skim coat went on ok but the final surface wasn't level. Thus, I did quite a wet mix to fill and feather.

Surface was prepped with dilute PVA.

What could have caused this? I did spray water on the wall to help work it and prevent drying out so wonder if that didn't help.

Is there any way of remedying this aside from hack it off? I am thinking of some Zinsser Gardz to stabilise it so I can paint over it.

Thanks all.

 

[PolarNorth78]

 

[PolarNorth78]

Update, Zinsser Gardz seems to have stabilised it a lot and worked a lot better than I thought. Painted without any issues.