I was sanding part of the plaster ceiling and upper wall (also plaster) which I had patched liberally sometime before. The sander is light enough to hold out with my arm fully extended and maintain control. I sanded about 4-5 hours off and on. The sander was able to reach into the corner between the wall and ceiling easily. It also did a surprisingly good job of dust control, surprising because I didn’t really expect much, I wasn’t smothered, and there was plaster dust in the little bag.