Tapeless Drywall Patches
Cut. glue. repair!
When cutting a hole in drywall, I use an oscillating multitool to make an inward sloping cut on each side so that the resulting cut-out piece can be reinserted into the hole (drawings below). When the time comes to replace the piece, I run a bead of construction adhesive around the sides to adhere it to the wall. Because the multitool created a small kerf, the patched piece sinks a little bit below the wall surface. So I fill in the depression and finish the edges with lightweight spackle. This takes a few coats with light sanding in between, but it creates much less mess than traditional taping and feathering with joint compound.
— David Matzinger, Menlo Park, Calif.