Are All Metals Detected by a Metal Detector?

Metal detecting is a fun and rewarding activity for hundreds of thousands of people across the world. Not only is it a great “treasure hunting” activity for families and friends, but metal detecting is also a popular solo hobby that can be enjoyed all throughout the year.

Just like the name suggests, a metal detector is used to be able to detect whether or not there is any metal in an area of the ground in which the metal detector passes over.

In addition to that, there are even some more advanced metal detectors that are able to detect metal that is present within the inside of different objects too, alongside being able to detect metal objects that are located deep within the ground.

However, even though the most basic of metal detectors will be able to detect a wide variety of metal detectors, unfortunately, due to the fact that metal detectors work to detect metals buried within the ground via electromagnetism, it does mean that metal detectors do come with certain detection limitations.

With that being said, it means that metal detectors will be unable to detect any metal or material that has very little or no electrical conductivity capabilities.

In addition to this, metal detectors will also be unable to detect any metal objects or elements that do not have any magnetic properties as just like we said above, metal detectors use electromagnetic properties to pick up on metal objects hidden deep within a surface.

In addition to this, metal detectors are also often unable to properly detect metal objects or metal hidden within another object that is very small in size. Even if the metal in question has plenty of electrical conductivity, due to the small size, it significantly lowers the chance of a metal detector being able to detect it.

Can aluminum be detected by a metal detector?

Yes, most metal detectors will be able to detect aluminum metal! So long as your metal detector has the correct settings and is equipped with the ability to detect a variety of different materials with electric conductivity, then your metal detector will no doubt be able to react to the electromagnetic field transmitted by aluminum material within close proximity of your metal detector. 

However, even though aluminum metal is non-magnetic by nature, it is still detectable by a metal detector.

In a nutshell, aluminum metal is a type of nonferrous metal (alongside other types of metal including brass, silver, zinc and even gold) that are becoming more and more easily detectable by latest-generation metal detectors.

This is because non-ferrous metals and objects that are present within the earth or under the ground are highly conductive and able to emit an electromagnetic field that metal detectors are then able to detect and pick up on.

If you’re just starting out in the world of metal detecting, then you might have a hard time being able to discern between valuable ferrous and non-ferrous metals, especially as there is a variety of non-valuable items that have little pieces of aluminum metal attached to them – such as beer cans!

Can metal detectors tell the difference between metals?

The answer to this question very much depends on what type of metal detector you are using. Generally speaking, many of the older metal detectors currently on the market (and even some of the more affordable options) are often unable to effectively distinguish the differences between metals.

Instead, even though these types of old-generation detectors are unable to detect the difference between different types of metal that reacts to its electromagnetic signal, these types of metal detectors are able to detect the presence of metal via its electromagnetic field, and then also determine the specific location of said metal. 

However, the case is often a little bit different for more advanced types of metal detectors, which often come equipped with a built-in metal detector that comes with something which is known as a “discrimination dial”.

To break it down, a metal detector that is equipped with a discrimination dial will allow the user to set the metal detector to only be able to detect a specific type of metal.

Due to this, it means that the latest-generation metal detectors have been made with the necessary technology to be able to tell different types of metals apart from each other. 

To continue on, even though not all metal detectors come with a discrimination dial, most modern metal detectors will be able to detect the difference between ferrous and non-ferrous metals.

Wondering how? Well, metal detectors are often optimized to be able to discriminate against non-valuable ferrous metal such as nails, and they can do this by forcing an imbalance within the search coils electronically.

With that being said, ferrous metal will decrease the imbalance signal, while non-ferrous metal (which is often more desirable) will increase the signal, and this will then cause the metal detector to begin buzzing or lighting up to alert the user that there is a non-ferrous metal worth looking at.

Can silver be detected by a metal detector?

Yes, metal detectors can very easily detect the presence of silver underneath an area of land! The main reason for this is because silver, among all the other types of metal materials out there, has one of the highest levels of electrical conductivity capabilities.

Thanks to this, it means that whenever a metal detector within close enough proximity to silver sends out its electromagnetic field via the search prod, the nearby silver metal will become energized and instantly send its own electromagnetic field back, which will then alert the metal detector. 

How sensitive is a metal detector?

The sensitivity of a metal detector will greatly depend on the quality of the metal detector. As a general rule of thumb, pretty much all metal detectors are designed to be able to detect large to small metal objects.

However, as a general rule of thumb, it is widely accepted that the better the sensitivity level of a metal detector, the better it will be able to detect very small and irregular shaped metal objects that would otherwise go undetected due to lower electrical conductivity, and mis-matched shapes.

What metals cannot be detected by a metal detector?

As you might already know, metal detectors are able to detect metals hidden deep within an area of the ground by using something that is known as electromagnetism.

In a nutshell, metal detectors work by transmitting an electromagnetic current (or field) from its search coil, which then shoots directly into the area of the ground that the metal detector is placed above.

As soon as the electromagnetic field is transmitted into the ground via the search coil, any metal objects (or object with electrical conductivity) will then become energized and begin transmitting their very own electromagnetic field, which the metal detector will then be able to pick up on and detect to the person who is using the metal detector. 

With that being said, there are some instances in which a metal detector will be unable to detect certain metal objects due to a lack of electrical conductivity.

This means that, when the metal detector is turned on and in use when it begins to emit its electromagnetic field from the search coil and into the ground, certain metals that have very low electrical conductivity or magnetic properties will be unable to become energized and transmit their own electromagnetic field in return, and in turn, the metal detector will be unable to pick the metal up.

Here are the most common types of metals and materials that is often unable to be detected by a metal detector:

  • Stainless steel
  • Diamonds
  • Pearls
  • Stone figures/objects
  • Glass
  • Plastic

How do metal detectors detect non-ferrous metals?

Non-ferrous metals are essentially metals or alloys that are not iron-based. Generally speaking, non-ferrous materials are often found within the Earth as chemical compounds, while ferrous metals are created either naturally or artificially to contain iron, which means that they, therefore, have magnetic properties that make them detectable by a metal detector. 

This brings us to the question, then, of how metal detectors are sometimes able to detect metals that are non-ferrous, and therefore do not become energized and emit an electromagnetic field.

Well, believe it or not, even though non-ferrous metals may not emit an electromagnetic field,  the non-ferrous metals, and materials that exist within the Earth as chemical compounds are actually very magnetic and have high electrical conductivity capabilities – which is the reason why metal detectors are then able to detect them.

These types of circumstances in which a metal detector is able to pick up on non-ferrous metals or materials are often known as “false targets” and can be very frustrating to the user who is metal detecting as it can interfere with actually finding targets that are valuable and are worthwhile digging into the ground to locate. 

Can stainless steel be detected by a metal detector?

Though it is possible for a metal detector to be able to detect stainless steel underneath an area of ground, it is significantly more difficult for a metal detector to be able to do this as opposed to detecting other types of metal materials or objects, such as copper or silver.

The main reason for this comes down to the fact that stainless steel has very low electrical conductivity and a lack of magnetic properties that make it extremely difficult for metal detectors to be able to pick up on stainless steel located within the ground.

Though it is by no means impossible and certain types of metal detectors will be equipped with the necessary technology to detect stainless steel, it will still be difficult for all types of metal detectors to detect stainless steel.

Why? Well, as we said, when a metal detector is in use, it will be able to transmit an electromagnetic field deep into the ground via the search prong, which will then energize any metal materials or objects that are in near enough proximity to the field.

Seeing as stainless steel does not contain as much electrical conductivity as other types of metal materials, it means that there is a stronger possibility of stainless steel materials being unable to become energized by the electromagnetic field of the metal detector, and in result, being then unable to be detected by the metal detector. 

Written by Danny Nash

I love metal detecting, history and sharing that with you. Read more of Danny's articles.


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