Repair

• 1). Move furniture out of the room and lay down a drop cloth. Use the bottle top opener to widen the crack in the plaster to approximately 1/8 inch in width. Scrape out loose plaster, making sure you wear a dust mask, safety goggles and work gloves for protection.
  
  
• 2). Vacuum out the inside of the crack with the shop vac. Use the spray mister to lightly dampen the area. Use a hair dryer on low heat for a few minutes to allow the area to dry.
  
  
• 3). Adhere the latex bonder to the horsehair plaster wall with a putty knife. Let it dry for 40 to 45 minutes. Fill the crack with joint compound or plaster of Paris. Each of these patching compounds has advantages and disadvantages. Joint compound applies smoothly and sands easily, but it takes 24 hours to dry, and it shrinks. You can use a hair dryer on low heat to expedite drying time, but be sure to apply the heat evenly to prevent the compound from cracking. Plaster dries in 2 hours, doesn't shrink, but is difficult to sand. You may want to simply add a bit of plaster to your joint compound for added durability.
  
  
• 4). Allow the area to dry completely for 24 hours or more. Sand with the sanding block and then wipe clean. Spot prime the area, let it dry and then paint it to match the existing walls.