Metal detectors are an important tool for many industries. They help find valuable items, protect against theft, and serve as a safety measure in dangerous situations.
Metal detectors have the ability to detect metal objects without touching them or damaging them. Hobbyists, jewelers, and manufacturers use metal detectors to find valuable items that may have been missed by a simple visual search.
But many people wonder whether or not a metal detector can find aluminum, and if so, why?
Can a Metal Detector Detect Aluminum?
Metal detectors can detect all metals that conduct electricity, including aluminum. Many treasure hunters and hobbyists find this out the hard way, as most metal detectors can’t tell the difference between a worthless aluminum can and a gold ring.
How Do Metal Detectors Work?
Metal detectors use a coil to generate a magnetic field. When currents are driven through the coil, an electric current will generate a magnetic field. The magnetic field will extend out from the center of the coil and set up a voltage across any object that crosses its path.
The presence of metal in the object is what affects the strength of this voltage, and the object’s composition is what determines how strongly it affects the magnetic field. This can be detected by a meter across from the coil that will generate a value depending on the strength of this voltage.
Metal detectors work using this principle of metal detection, but they have been further refined to detect more specific objects and perform certain functions. In order to detect specific objects, metal detectors need to use a discriminator circuit and signal processor. This will allow the device to distinguish between metals and ignore non-conductive materials like wood and plastic.
How Does a Metal Detector Find Aluminum?
Aluminum, like all metals, is conductive, and it can generate a voltage when set across the magnetic field of the coil. This means that metal detectors will be able to pick up on aluminum. They won’t be able to tell what exactly they’re finding until they’ve found it, though metal detectors do have a number of signal processing tricks they can use to help them when looking for specific objects.
The issue with metal detectors and aluminum comes from their ability to work with the composition of a metal object. Different metals have different permeability values, which means that each type of metal will affect a magnetic field differently. This is what lets a metal detector distinguish between types of metal, but it can’t do this with aluminum.
Aluminum is very close to the permeability value of air, so detecting differences between objects becomes much harder. This can be mitigated by looking for dents or marks on aluminum objects – dents are often a result of manufacturing processes that leave small bits of other metals in the object.
How Deep Can a Metal Detector Detect Aluminum?
A metal detector can detect aluminum fairly deep down in the ground, but not nearly as deep as other metals like iron or gold. Depending on the concentration of aluminum and how conductive it is, a metal detector can generally detect aluminum to around six inches (15 cm) below the surface.
Some higher-end metal detectors can detect aluminum as deep as 12 inches (30 cm) below the surface. The deeper a detector detects aluminum, the more conductive and purer it needs to be.
Conclusion
Just like other metals, metal detectors can also detect aluminum objects just fine. However, you won’t know what is buried under the surface until you dig it up, and most of the time, it’s just an old can!
If you want to detect treasure with a metal detector, it’s best to use a gold or silver detector. There are also detectors that can be used with computers and apps for even more accuracy.
