I am restoring an old house. The finish coat of plaster in the front hallway wasn’t bonded to the scratch coat in many areas. The traditional fix is to inject white glue between the coats. But white glue takes a long time to dry. I tried something different — cyanoacrylate adhesive (CA). This glue, which is available at hobby shops, is good for gluing porous surfaces. It’s strong, wicks well into tight places and sets up fast.
I started my plaster fix by drilling 1/8-in. holes on approximately 8-in. centers. I then squirted the CA into the holes and held pressure on the area for 30 seconds. The finish coat bonded beautifully to the scratch coat. You can get CA in different viscosities. The thin stuff wicks better; the thicker adhesive is better for filling gaps.
Mark Shilling, Raleigh, NC