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History of metal detectors
Since the early 1900s, when gold was discovered in new lands, people have been looking for metals to find other valuable things. One of the first tools used by miners to find these materials was a metal detector.
These detectors work by detecting magnetic fields, which are electromagnetic effects that attract or repel certain metallic objects. Metals typically have more magnetic flux than non-metallic materials.
Magnetic fields also affect any metal you show them. This includes rings, bracelets, earrings, etc.
This article will give you some history about metal detection technology as well as how it works. You can then decide if this type of hobby tool is right for you.
There are many different types of metal detectors available today. But which one you choose depends on your budget and personal preferences.
Some of the most common varieties include basic “laboratory” models, complex survey models, and aerial laser scanning devices. These generally cost anywhere from $500 to $5,000, but do offer customizable features.
Survey meters, on the other hand, are cheap compared to the laboratory model. However, their quality is less consistent, as they tend to be more user-friendly. They vary in price from $20 to $100.
Cheaper alternatives can be found with online retailers who sell second-hand equipment. For example, an old magnetometer (for finding iron) might just sit around until
How metal detectors work
Now, let’s talk about how metal detectors actually work. Most of them use either electromagnetic induction or high-voltage breakdown technologies to detect objects in hard soil. (In general, these two techniques are used together.)
Electromagnetic induction is the most common method for detecting aluminum in moist soil, because it is less dependent on the shape of the object. Think of a hand tap as an alternative way to induce current into a wire.
When a conductor (a metal ball, couch cushion, etc.) gets near another conductor (the antenna coil in your detector), it changes the local magnetic field. The induced energy moves the magnet within the inductor, which acts as a receiver for the signal.
This helps the detector “find” metallic objects. For example, when you hold a coin next to your ear, you are transmitting electricity through your skin and creating a small electric charge. This creates an alternating current that induces voltage in the antenna of your detector.
You can also find metals by raising the internal temperature of the detector engine enough to vaporize/distinguish between more expensive steels and nickel alloys. After the evaporation process, only the heavier elements remain.
What types of metal detectors are available?
There are several different styles of metal detector to choose from, depending on your target audience.
The most common type is the hand-held detector, also known as a portable detector. This can be used by anyone regardless of their weapon training or fitness level.
Many are affordable – under $500. And although they may seem expensive, these are extremely valuable tools that you should invest in.
There are other versions of handheld detectors as well; one has a keyboard for typing words, others have sensors that help detect metals.
How to use a metal detector
There are many ways to detect metallic objects. Most handheld detectors will have you place your hand over or next to a target object, then it will beep when it goes off.
Some find this very tricky to do, but there are other methods as well. One of the most common is called “palming” an item. This method can be used with any device that detects proximity by measuring electrical resistance.
When you palm something, you hold your hands like you would for throwing a football or swinging a tennis ball. You don’t make the movement mechanical-you just try to hit the object. Palming only works with some kinds of balls, though.
Palming means applying constant pressure without moving again until the item has been completely thrown. Because of how thick aluminum foil is, if you simply press down on it, it won’t pop up in the air very much and it will take lots of effort to knock it away after it lands.
Pressure must be maintained even through the moment of contact so the two sides stick together before separating. Apply too much pressure and the thing will start coming apart before it hits the ground.
Avoid digging around old coins
When gold prices were high, people would buy lots of singles to store for sentimental value (and fun)
They’d often put these coins in bags or boxes then forget about them.
But what do you think was more likely to set off a metal detector – the coins themselves or the bag they came in? It turns out that coins are much heavier than plastic bags and can make your detector go off with heavy objects.
And even if there weren’t any coins inside, you might have put old nails or other metals from the packaging into your storage container. These are harder to detect but could also trigger an alert.
Therefore, when you are putting together items for your personal collection, don’t forget about the packing material. That zinc seal against your box lid is far lighter than the metal content within it!
Know your detector model
There are hundreds of metal detectors to choose from, so there’s sure to be one that fits what you need. However, just because a device is labeled as “metal detection” doesn’t mean it can find things like aluminum foil or coins.
Detectors have been making claims for decades- some true, some not.
If you’re looking into buying a detector, ask about the model’s ability to detect metallic items. Also ask if the instrument can be set up to filter out backgrounds. Many instruments can actually recognize several elements other than iron, suchas copper and gold.
When choosing a detector, look for guides online that list what specific models work well with certain materials. A basic rule to follow is whether an item will moveor emit a signal depends on the shapeand materialitself.
Detection equipment has advanced considerably in recent years, allowing for more accurate readings and less risk. Still, all detectors require calibration, either by taking them to a certified instructor or using internet apps.
Finding something at camp or during exercise requires practice and proficiency. Without both, expect occasional misses and maybe even a lot of people complaining.
Know your detector settings
There are many things you can tweak to make your detector go faster and get more hits. But, if you’re looking for something specific, it is helpful to know how to adjust the settings so you can detect objects more effectively.
Most detectors have a setting called sensitivity that will affect the depth of the signal you find.
You want the highest possible sensitivity so you can set the most sensitive mode your detector has to offer. The higher the sensitivity, the more potential there is to dig up false alarms, but you may hit upon something interesting sooner.
If you don’t feel like changing the sensitivity manually, you can use a plugin for your control panel. Many people prefer this over-the-top detection because they think it gives better results.
There are many ways to detect metal objects hidden in food, and most of them use your skin as the sensor. You’ll be unaware of any metal objects right under your skin, so this is a safe method for measuring metallic substances.
When you eat or drink something, the acidity of your saliva causes ionization of some water molecules in your mouth. The slightly positive ions from the saltwater in your meal migrate through your saliva toward your tongue, causing it to “feel” electric.
The more of these charged particles that flow away from your tongue, the higher your risk of developing dental issues such as cavities. This is why salty foods may cause tooth enamel to wear down.
Metal conducts electricity better than most other materials does, which is what makes metal detection possible. In people with high blood pressures there is also a greater chance of getting headaches.
Cleaning metal objects
If you find an old weapon, tool, coin, or other metal item at the beach, your first thought might be to put it in some form of protective casing to prevent more sand from getting into the device and interfering with the electronics.
While this is a good idea, there are better methods than covering them with aluminum foil. With enough pressure, even delicate items can break free from inside and come out intact.
But for smaller items like rings, keys, or other small accessories, now is the time to use that foil blanket. Letting these items sit with the included paper bag for 5-10 minutes should do the trick.
If you need something bigger, then below are several helpful tips.