Hi, Doug. I have the same problem and it is difficult. Our daughter has a 160 year old house with lath and plaster--and some studs are installed sideways to today's normal. I have a Zircon 4.0 stud finder and it is very difficult but does work--sort of. What you have to do is start from several different locations on the wall and makr where the stud seems to be, then develop a consensus and you should be pretty close. Forget an $8 unit. You will spend $20 to 30 to get a stud finder that works. Units with more sensativity and that can tell you about pipe, electric wires, etc, are available for even more.