I am doing some remodeling and have sections of drywall that have to be plastered to match the thickness of the remainder of the wall. I tried using plaster of Paris, which should be workable for 20 mins. However, whatever I try, it sets in the tray after a couple of minutes and is to be thrown away. Does anyone know what I did wrong. I used the recommended amounts of water and tried more and less water, all to no avail. Maybe I don't make enough in one time?

 

You might want to try drywall compound. There are some good pre-mixed ones. Plaster of Paris isn't really something you should use on walls. I don't think it would stick.

 

Thank you Lauraa, I will follow your advice.