Metal detectors emit an electromagnetic field to detect conductive objects in the ground. From casual hobbyists to professional archaeologists, metal detectors have become popular for discovering hidden treasures and artifacts. This ultimate guide to metal detectors will explore how these machines work, what they can detect, and how they perform under various conditions.
At its core, a metal detector emits a magnetic field through a coil, which induces a current in the conductive objects in the ground. The metal detector then detects and amplifies the changes in the magnetic field caused by the metal object, alerting the user through a sound or visual indicator.
While metal detectors are commonly used for treasure hunting, they are also used in various industries, including construction, mining, and security. Understanding the basics of how metal detectors work, what they can detect, and their various features is essential for anyone looking to purchase or use a metal detector.
Key Takeaways
- Metal detectors detect conductive objects such as gold, silver, iron, and lead by emitting an electromagnetic field that triggers electric current in the target item, causing a change in the electromagnetic field’s shape that the machine can sense.
- Multi-purpose machines are needed to detect all possible metals. Gemstones cannot be directly detected but found near gold mines or volcanic pipe lines. Non-metal items such as pearls, glass, papers, stones, bones, liquids, plastic, and raw diamond cannot be detected.
- The performance of a metal detector is limited by factors such as the detector’s frequency, the target’s depth, and the physical capabilities of the detected item. Unfavorable weather conditions, dry or wet soil, and mineralized soil can also limit its performance.
- Pulse Induction and Very Low Frequency are two types of detectors that use waterproof detection technologies. Pulse Induction is ideal for detecting metals in saltwater beaches and when diving, while Very Low Frequency is generally used for coin shooting and finding relics and jewelry. Small items can be found with high-frequency detectors, while handheld and needle/staple detectors are highly sensitive to small metal objects.
What Metal Detectors Detect
Metal detectors are designed to detect conductive objects, such as gold, silver, iron, and lead, by emitting an electromagnetic field that triggers electric current in the target item, causing a change in the electromagnetic field’s shape that the machine can sense.
This technology allows for applications beyond treasure hunting, such as airport security screening and detecting landmines.
However, there are common misconceptions about metal detection, such as the belief that all metals can be detected.
Non-conductive objects, such as pearls, glass, and plastic, cannot be detected. Also, gemstones cannot be directly detected, but it is possible to find them near gold mines or volcanic pipe lines.
Understanding the limitations of metal detection technology is crucial for accurate and effective use.
Types of Metals
Valuable metals can be differentiated from less valuable metals based on their resistance against corrosion and magnetic properties, making them more sought after by treasure hunters.
Valuable alloys detected by metal detectors include gold, copper, silver, meteorite, platinum, and tungsten. These metals are highly corrosion-resistant and have high magnetic properties, making them ideal for use in electronic devices and jewelry.
On the other hand, less valuable metals that metal detectors can detect include brass, titanium, bronze, aluminum, lead, and nickel. These metals have lower resistance to corrosion and lower magnetic properties, making them less valuable and sought after by treasure hunters.
Additionally, metals can be classified into ferrous and non-ferrous categories based on their magnetic properties and iron content. Ferrous metals contain iron and are magnetic, while non-ferrous metals do not contain iron and are non-magnetic.
Valuable metals such as gold and silver are non-ferrous, while iron and steel are ferrous. Understanding the differences between ferrous and non-ferrous metals is important for treasure hunters when using metal detectors to distinguish between valuable metals and scrap metal.
Metal Detector Performance
Factors such as frequency, depth, and environmental conditions can influence the effectiveness of metal detection devices.
The frequency of a detector determines the size of the objects it can detect. High-frequency detectors are more effective at detecting small objects, while low-frequency detectors can detect larger ones.
The depth of the target is also an important factor. The closer the detector is to the target, the stronger the magnetic field is on the metallic target, making the sound louder. Detection devices can see objects buried at a maximum depth of 15 inches in clean ground conditions. The depth can be reduced to 7, 8, or 10 inches in trashy ground conditions. Using a larger coil can improve the depth. The larger the coil, the deeper the device can go. However, larger coils may not be as effective in detecting small objects.
Unfavorable weather conditions can also limit metal detector performance. Dry or wet soil can cause underperformance. Mineralized soil presents a big challenge to metal detectors.
Understanding the factors affecting metal detector performance is crucial for maximizing the device’s efficiency. By considering these important factors, metal detector enthusiasts can increase their chances of finding valuable objects and treasures.
Frequently Asked Questions
Can metal detectors detect non-metallic objects?
Metal detectors cannot detect non-metallic objects such as pearls, glass, papers, stones, bones, liquids, plastic, and raw diamond. Limitations of detection include the detector’s frequency and the item’s physical capabilities. Alternative detection methods include handheld detectors and needle/staple detectors.
Why can’t gemstones be directly detected by metal detectors?
Gemstone identification is not possible with metal detectors because gemstones lack electrical conductivity. Metal detectors detect conductive objects through changes in the electromagnetic field, but gemstones do not produce such changes. However, gemstones can be found near mineral deposits.
What is the difference between ferrous and non-ferrous metals?
Ferrous metals contain iron and are magnetic, whereas non-ferrous metals do not contain iron and are non-magnetic. The corrosion resistance of non-ferrous metals is higher, making them more valuable. Magnetic properties determine a metal’s ability to be detected by metal detectors.
Are there any weather conditions that can limit the performance of metal detectors?
Humidity and rain can negatively affect metal detector performance by causing false signals and reducing detection depth. Ground balance is crucial to compensate for mineralization and maintain optimal performance in varying weather conditions.
How do handheld detectors and needle/staple detectors differ from larger detecting devices in terms of sensitivity?
Handheld and needle/staple detectors are highly sensitive to small metal objects, while larger detecting devices have lower sensitivity and cannot detect smaller objects. However, both types of detectors are limited by detection limitations and environmental factors such as soil mineralization and unfavorable weather conditions.
