Metal detectors of all kinds are a familiar sight today. You see hobbyists with portable hand-held models, looking for coins, jewelry and other valuable items in parks and on beaches. Different kinds of metal detectors help protect airports, courthouses, schools and other public and private buildings.
These very same detectors have other uses that are not as well known but extremely important to business and industry - applications far beyond treasure hunting and security. In fact, the results that detectors offer industry are limited only by the imagination.
During the past 50 or so years, detectors have been used to detect and locate practically every kind of metal and detectable mineral. As their functions have come to be understood more clearly, metal detectors have grown more and more popular, especially in the construction industry.

Construction industry applications
These ingenious instruments speed up the performance of many tasks for builders and handle others that simply defy human effort.
Take locating underground pipes, for instance - or electrical conduits or land markers. Imagine the inconvenience and expense involved if a bulldozer's blade rips into a buried cable containing thousands of telephone lines. Results would be even more disastrous with a gas line or electrical conduit.
To avoid needless destruction, field crews scan the ground with a metal-detecting device - a relatively inexpensive and easy measure - before digging, trenching or disturbing the location in any way.
Metal detectors can trace and locate metal objects that are not visible to the human eye for whatever reason, the most obvious of which is that these objects are buried in the ground or hidden behind walls. Using a metal detector is a quick, simple and inexpensive alternative to digging for buried pipes or tearing out walls to find hidden wiring.
"Where are the studs?" the carpenter wonders in the middle of the remodeling job. You could spend a lot of time banging on the wall and still not be sure. But the metal detector can solve this problem in a hurry. Just listen for those insistent "beeps" when it locates the nails in the studs.
How about cleanup after a construction project or roofing job? You can save time and get the job done a lot more efficiently if you use a metal detector to find those nails and other small pieces of trash metal that have been spilled all over the ground.
The location of metal reinforcing rods is highly important in concrete construction. Determining the location of rods after the concrete has hardened is next to impossible without metal detectors. These instruments quickly point out the exact location of any metal in a concrete slab, floor or wall.
If a question should ever arise about the amount of rebar in a concrete construction project or where rebar is located, a detector can provide the answer quickly and easily.

A natural for rental centers
Because of their growing popularity, metal detectors are becoming more prevalent in the rental industry. Their low initial cost and near-zero expense for maintenance makes them highly profitable.
Today's metal detectors are sophisticated electronic instruments but all of them find metal simply through the transmission and reception of radio waves. The signal produced in the search coil of a metal detector generates an electromagnetic field that flows out into the surrounding earth, wood, rock, concrete, air or other material. When the field encounters a metallic object, the detector reports its presence with an audible signal.
Various manufacturers require different types of detectors for unusual metal-detecting jobs. Some of these manufacturing and processing applications are pretty inventive.
Lumber mills use detectors to search for nails, spikes and wire in trees and logs. A single nail or spike can destroy a sawblade - which can be extremely expensive - and worse, maim or kill anyone nearby.
Metal detectors are widely used in food processing plants to locate "tramp" (unwanted) pieces of metal that may have broken loose and fallen into food processing containers.
A foam rubber manufacturer had a problem with a foam rubber reclaim-er. As foam was processed, it came out of the machine in sheets six feet wide by six inches thick. A heater wire cut the foam into layers of various thicknesses as it came out of the machine. But often metal objects such as pins were present in the foam, and when the foam was pushed into the heater wire, the metal touched the wire, causing it to break. The solution? A metal detector, of course. What else?
Here are some more imaginative applications for metal detectors of one kind or another in current use:
Locating staples during automatic processing of paper money.
Counting items going through food processing plants, such as cans.
Checking bales of foodstuffs for "tramp" metal.
Locating metal objects concealed in farm fields where they would damage farm machinery.
Searching hospital trash for surgical instruments lost accidentally.
Detecting metal objects mixed with ore or coal in processing plants.
Locating silverware inadvertently discarded with restaurant linen.
Locating pipes and fire hydrants covered by snow, sand or mud after earthquakes, avalanches or landslides.
More metal detectors might be in use if rental centers made the effort to help people understand how a metal detector can be used to solve a problem and demonstrated for them the simple procedures required to locate concealed metal objects.