I wouldn't give up on the stud finder. Like I said, the trick to using it is that you can't start it over a stud or other obstruction. Put it flat on the wall and press the button, let it calibrate, then move it around. Do that a couple times, turning it off in between attempts. Try it higher and lower on the wall, or left and right. When it hits 16" (or maybe 24") on center, you've found your studs.