Just a tip about a Metal Detectors
You may have one in your tool box and just don't know you do..
It's called a Stud Finder, I started to think how they work and it must be the same as a metal detector....
They don't just detect studs, they do detect nails and screws in the studs also.
I should say they do both detect wood and metal.(via.density differences)
I the one I have is a (Zircon) (StudSensor Pro.) I got it out and low and behold it works on used lumber ..
just like a Metal Detector.
The Zircon looks almost the same as the Little Wizard Hand Held Metal Detector but it's yellow plastic with more flashing lights.
Here's a link to the Zircon web site but this is just one of the many stud finders on the market today.
http://www.zircon.com/
Hope this helps someone that wants a Metal Detector
Bj