Over time the crack in the plaster just behind SWMBO's bed-side table has been getting bigger. Depending on circumstances, I've used various techniques to repair the damage or holes. With the tuckpointing coming on the south elevation, we've had the structural engineer out for a consult on other things. He looked at this and didn't think tearing it off was necessary.
This means that a true repair is still a possibility.
I've been a member of an evolving list of old house sites on the internet and through them became aware of a product I'm going to try for this repair:
Big Wally's Plaster Magic. (Note - no affiliation and no sponsorship...)
In this instance the plaster has cracked and come loose from the underlying lath, especially on the right side of the crack.
And off we go, following the instructions.
I drilled holes through the plaster with a 3/16 masonry bit, making sure to hit the lath. The crack had separated enough that locating the lath wasn't that difficult.
I then vacuumed out all the holes and the crack and squirted the conditioner in every hole.
After waiting the suggested 10 minutes, I used a caulk gun to squirt the adhesive into each hole as directed. The adhesive was runnier than I expected, but no harm resulted. There was just a little more cleanup with a damp rag and bucket of water.
Lastly I used the included screws and washers to clamp down the loose plaster and try to get the right side more-or-less at the same level as the left. And wait for the adhesive to dry/cure.
I waited about 36 hours and then began removing the screws and washers. Everything seemed well-adhered, so it was time to mud and tape. I'm using fiberglass mesh, rather than paper tape, which should give us better long-term results. I've applied it to some other minor cracks as well.
Now I wait for the first coat to dry. I'm sure it will take two or three coats to get it feathered out so that I'm happy.