I installed chair rails for my sister in her new rental home. All went
well except two minor issues. In one room, with my Zircon I520 deep scan
stud sensor, I cannot locate a stud to fasten a section of the rail and
thus, there's a slight gap. On the other wall in another room, I'm
dumbfounded at what's behind the wall. First, I'm uncertain if I found
the stud since the sensor was a bit fuzzy. Second, when I shoot a nail
in that area where I think it's a stud (BTW, I'm using 2" brad nails),
the nail is curving backwards and exiting the front of the rail and not
even penetrating the wall. The ends of the rail are near a window, door
and/or room opening. Therefore, there should obviously be a stud, but
the end of this same rail also curved back at me on one end but stuck at
the window end.

Without shooting nails in the entire rail trying to find a stud and
creating holes to fill, I'm uncertain of how I should attempt to fasten
these small sections and only two options come to mind. One, try using a
finish nail for the curving nail issue and create bigger holes to fill,
though still uncertain of stud location or two, use adhesive.

What say the experts?