Patching deep holes in plaster over brick
I have a 100 year old brick twin in Philadelphia. I'm getting ready to paint the living room, stairs, and second floor hallway. The previous owner installed a railing for the stairs. There was already an original wood railing; I assume this other railing was just an added safety measure, but it's not necessary and definitely not original, so I took it out. It was installed directly into the wall, which is approximately 1 inch of plaster directly over brick. They drilled holes about 1 inch or so wide and maybe 3 or 4 inches deep, inserted wooden dowels, and drilled the mounts for the railing into the dowels. So the holes are quite wide and deep, going all the way through the plaster and a few inches into brick and mortar. I would like to fill those holes and paint over them. I'm just wondering what would be a good patching material for holes this deep in plaster and brick. Drywall joint compound has been my go-to patch for other projects, but it seems like I might have a hard time getting it that deep into these holes. I was thinking about maybe just cutting some wooden dowels to fill most of the space and then patching over that with setting type joint compound.