S is for Stud sensor

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S is for Stud sensor

This is a stud sensor (1). It is used to detect studs, the vertical pieces of wood that support the weight of the wall. Why do I have a stud sensor?


Did you ever see that episode of the old "Dick Van Dyke Show" when Rob Petrie pounds a nail into the wall and a gush of water sprays out? This is, of course, after he's had a tiff with his wife, Laura, over whether he has the handyman skills necessary to do something as simple as hang a picture. In the process of driving the nail, Rob missed the stud and punctured a pipe he didn't know was there. Rob's efforts to contain the damage (before Laura came home from shopping) spiraled out of control, growing more and more frantic and slapstick with each passing minute. The wall erupted with water, the floors and wall were badly damaged and all the furniture in the room was ruined (2). Hilarity ensued.

No? You never saw that hysterical episode? How about when the exact same joke was done in just about every "dad is just a dope" sitcom since 1961?

Doesn't ring a bell? Seriously?

OK, how about the episode of "All in the Family" where Archie Bunker was trying to hang a picture, but instead of puncturing a pipe in the wall, he hit a live electrical conduit. The shock burned off the fingertips of the hand he was using to hold the nail, frying his flesh right to the bone. Also, the electrical fire that started inside the wall (which Archie, tending to the 3rd degree burns on his fingers, didn't notice until it was too late) spread vertically until it burned down the entire building (3). Archie, his wife Edith Bunker, his daughter Gloria Stivic and his son-in-law Michael "Meathead" Stivic are left bankrupt and homeless, since insurance doesn't pay much for homeowner-caused damage. Hilarity ensured.

No? Didn't see that one either? Doesn't sound very funny, does it?

The fact is, we need to do stuff to our walls. Hang pictures or mirrors, attach moldings, install lighting fixtures, etc. All of this involves breaching the integrity of the wall surface, whether it's old plaster and lath or modern drywall. If only we could be sure that there was nothing BEHIND where we were about to drive that nail, screw or wall anchor, life would be much easier. Ideally, nails and screws should be driven into the studs. If you drive them into the space between the studs, the only thing that's holding it in place is the drywall. For light items, that might be OK, but a heavy item will just tear itself out of the wall.

You can often find the studs by rapping with your knuckles and listening for the change in sound. The spaces between studs go TOCK TOCK TOCK, while the spaces right over the studs go TICK TICK TICK. Usually. But sometimes it's hard to tell a TOCK from a TICK. Also, there's no way to know for sure where the pipes and wires are in relation to the stud. If you have one running vertically alongside a stud and you miss the edge of the wood by a quarter-inch, you suddenly find yourself in the role of Rob Petrie. Or worse, Archie Bunker.

The stud sensor pictured here was something like $15. I assume it uses ultrasound to penetrate the walls during detection mode, but I'm not really sure. It might use oscillating magnetic fields, or maybe vaporized unicorn saliva. Anyway, it will sense the change in density behind the wall and light up the LED array to tell you exactly where the edge of the stud is. It also projects a handy red line upward for marking. Since old plaster and lath is much thicker and denser than modern drywall (thanks to the heavy cement lath treatment under the base coat and skim coats of plaster), this stud sensor has a "Deep Scan" mode to penetrate that extra-heavy wall.

For added security, this stud sensor also has a sensor that detects live electrical current. This element HAS to be oscillating magnetic fields that will induce a bounce-back signal in copper wires. It's a nice feature, not only for avoiding the wires when hanging a picture, but for tracing the wires through the walls when installing new light fixtures.

As much as I love homeowner hilarity, I have no desire to puncture a pipe or clip a wire. A stud sensor is an easy to use tool that lets me put my nails exactly where I intend for them to go.

1. It makes a loud beeping sound every time I pick it up (4).

2. I've had basement floods due to a ruptured water heater, a shorted-out sump pump that failed during a hurricane and a bad electrical installation. They were always expensive and never funny.

3. This didn't really air. Houses destroyed by electrical fires aren't as funny as houses destroyed by water damage.

4. And I make this joke every time I pick it up. Never gets old.

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  1. I have one of these as well. And my brother makes the same joke... of course, he had to explain it to me (brothers never associate "stud" with each other).

    There was, way on back in my childhood, a low-tech version that was simply a gimbal-mounted magnet. It would lift itself up when passed over a nail, which meant you did a lot more scanning and sliding around before you found the darn thing.

    1. Yeah, that's an old joke - just as funny the 1000th time as the first, i.e. not very (but what the heck).

      My father-in-law told me about holding a magnet and running it across the wall, feeling for the pull of the nails. I tried it, then went out and bought the stud sensor.

  2. Your insecurity over other people's Nick At Nite habits were fun to read, Tony. At least I remember that trope, and have lived my way into it a few times. Ignorance is a great way to begin learning.

    1. No Nick at Nite for me. I watched both of those over-the-air: "Dick Van Dyke" in reruns, "All in the Family" when it first aired. I remember when it switched to "Archie Bunker's Place", too.

      I would offer this slight tweak: we all start ignorant, but it's awareness of your own ignorance that is the start of learning.

  3. Now this is an interesting theme for the A-Z. Had no idea there was a too such as this. Guess because we have concrete walls.

    1. For concrete walls with an overlay of drywall, there are usually face-studs - strips of wood that are glued to the concrete. The drywall is attached to these face-studs with screws. This stud sensor would probably work to find them.


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