I am putting down vinyl cove moulding. The otuside corner in question has been bullnosed by me about a year ago using the usual metal bullnose material. I think what I used to set the bullnose was 20 minute fast set patching compound.
Anyway, where it is unpainted at the bottom it is very crumbly. I am doubtful the cove moulding will stick at all (seperate adhesive type) or if it did stick would hold up to a bump without crumbling.
Where it is painted it is stronger, although still not strong as I would like. How do I get a good hard plaster surface? When I was a kid I played around with pure plaster of paris and know it can form a hard surface. What product should I use?
Second question. I have toyed with the idea of ripping off the lowest 3" of sheetrock and replacing it with same thickness plywood to make a base for vinyl cove moulding that can really take it. I decided against doing it at this time because it is a live-in project. What my second question is, is installing a plywood base down there like that a common practice? Or is it seen as unnecessary?