You will need a powder that is specifically made for repairing plaster, such as Bondex brand. You will also need water and a putty knife. Mix the powder with the appropriate amount of water until it forms a thick paste. Apply the paste to the surface of the plaster and use the putty knife to smooth it out. Let it dry completely and then paint over it.

To repair plaster, you need to purchase a plaster kit that includes the necessary tools and materials. The kit will typically include a patching compound, a spreader, a putty knife, sandpaper, and a clean cloth. First, remove all of the loose plaster from the area that needs to be patched. Then, using the putty knife or the spreading tool that came with your kit, apply an even coat of the patching compound to the area. Be sure to smooth it out as you go so that there are no bumps or ridges. Allow the compound to dry completely (usually 24-48 hours). Once it's dry, sand it down until it's smooth. Finally, paint over it with latex paint