Yes, neodymium magnets are very strong and can be used for water searches. They are often used to search for metal objects at the bottom of rivers, lakes, and the sea. Neodymium magnets can also be used to hold or move metal objects underwater. However, it's important to remember that neodymium magnets are very strong and can be dangerous, so caution should be exercised when using them. They are extremely durable and can last for many years if properly cared for. Recently, magnetic holders for water searches have become popular - here's a brief description.
Which neodymium magnets for underwater searches?
If you're wondering which neodymium magnets to choose for underwater searching, we recommend two UMP 75x25 [M10x3] GW F200 GOLD DUAL Searching Magnets.
They are perfect for treasure hunting in rivers and lakes due to their strong pull force of ~ 600 kg.
If you're just starting out, a good starter option would be UMP 75x25 [M10x3] GW F200 GOLD Lina Searching Magnet with an included rope for searching.
It's an optimal choice given its balance between strength and price. It has two side mounts and one top mount, allowing for versatile use during searches. To learn more about the differences between magnet mounts and their pulling force, we encourage you to watch a video on YouTube. Also, consider visiting our store where you'll find search kits, including magnetic holders and essential accessories for underwater expeditions.
What magnet holder to buy and which ones to avoid?
Remember! Before making a purchase, check the number of Gauss (millitesla) - this determines the lifting force, not the text on the box.
The more Gauss, the stronger your magnetic holder for searches will be, and the more finds you will discover. Note that the holder has full power when using the top attachment - the side attachment is 10%-25% of the declared power. It is well-known that stronger magnets can attract objects from a greater distance (greater range) and can be used to retrieve even heavier objects, but it is not always worth adding 50% of the price (200 PLN + 100 PLN ~ 300 PLN) for a magnet that is 10% ~ 20kg (290 kg + 20 kg ~ 310 kg) stronger.
Our best-selling magnets in the store are from the GOLD series:
- UMP 67x28 [M8+M10] F120 GOLD Lina Magnet double-sided with a lifting capacity of ~120 kg, labeled F120 GOLD HOLOGRAM N38. Recommended for children; for adults, we suggest stronger models.
Great for keys, but not for retrieving an iPhone 14 from water.
- UMP 75x25 [M10x3] GW F200 GOLD Lina Magnet double-sided with a lifting capacity of ~290 kg, labeled F200 GOLD HOLOGRAM N42. An ideal balance between strength and price.
- UMP 94x28 [M10] GW F300 GOLD Lina Magnet double-sided with a lifting capacity of ~330 kg. A perfect blend of power and value for the price.
- UMP 94x40 [M10] GW F550 SilverBlack Lina Magnet double-sided with a lifting capacity of >600 kg - this is our most powerful model.
Other advanced models like F400 GOLD or F600 GOLD are perfect for professional searches, but might be underestimated for retrieving undrowned Samsung or iPhone smartphones.
Sliding Force [parallel] (side ear) vs. Adhesive Force [perpendicular shearing] (top ear)
The sliding force of a magnet [side ear] is the force that acts on the magnet when it tries to slide along the surface of another material, such as metal or iron. It is a resistance force that arises from the interaction of the magnetic field of the magnet with the magnetic fields of the material it moves over. The greater the sliding force of the magnet, the harder it is to move it along that surface.
The adhesive force of a magnet [top ear] is the force that acts on the magnet when it tries to attract another ferromagnetic material, such as iron or steel, towards itself. It is an attractive force that arises from the interaction of the magnetic field of the magnet with the magnetic fields of the material it attracts. The greater the adhesive force of the magnet, the stronger the attraction to another material.
When it comes to neodymium magnets in holders, we determine the lifting force for each of them by using the letter F - Force. This is why we often get the question why magnets do not always support a certain load. What is the difference between the force of holding by the top ear (perpendicular), and the shearing force or sliding force of magnets (side ear)? It's best to illustrate this with an example of a magnet with a force of F200 kg. However, when we attach the magnetic holder to a metal sheet on the wall, it will not withstand the declared load, and sometimes the magnetic holder itself slides down. But when we attach it to the ceiling, it cannot be detached...
What equipment do I need for magnet fishing?
The mandatory equipment is a magnet with a holder (preferably UMP 75x25 [M10x3] GW F200 GOLD with Rope set price ~ 200 PLN). Without it, you won't go far ;)
Optional equipment includes:
- Protective gloves. To avoid injury from sharp objects - they are included in the set,
- Bucket / box / bag. So you have somewhere to put the retrieved items and take them home or to a collection container. Leaving a large amount of scrap on the shore doesn't look good. Responsible treasure hunters leave not only a clean river but also a clean shore,
- Cloth for wiping hands and the magnet holder. This will extend the lifespan of the magnetic holder,
- Steel hook. Heavier finds such as bicycles, motorcycles, or benches cannot be retrieved using a magnet alone - use a hook for the rope,
- And if you have a hook, you'll need an additional rope to attach it.
Magnetic Force in kg or N?
If you are a knowledgeable physicist, you probably know that the magnetic force should be correctly given in newtons - N. However, we intentionally provide it in kilograms - kg, so that the information about the magnetic force is more understandable even to a broader lay audience. Information about how many newtons a magnet or a magnet holder can hold means nothing to most laypeople. But indicating how much weight it can support is generally more understandable.
For clarification: 1 kg of weight corresponds to a force of 9.81 N.
The magnetic force on a perpendicular surface is only 15-25%
What is the difference in magnetic force when it acts perpendicularly to the surface compared to the lateral shearing force?
This depends on the surface to which you attach the magnet, the thickness of the metal, iron, or steel base, and also how you use the magnet.
Whether the magnet only holds paper on a magnetic board or it is a magnetic hook attached to the side of the refrigerator, where a bag of legumes is also hanging.
The force of the magnet, when loaded parallel to the surface of the substrate, is only 15-25% of the magnet force we mentioned. The magnet will attract ferromagnetic materials in the direction of the magnetic field.
What does the magnetic force depend on and how does it change according to the direction?
If you attach a magnet to a vertical surface, such as a steel plate on a wall or a refrigerator door or a metal cabinet, the magnetic force will be weaker. However, this also depends on other factors. In the case of placing the magnet on a vertical surface, the shearing force also comes into play. It increases or decreases depending on the friction between the magnet and the supporting vertical base. If you attach a shiny, nickel-plated magnet to a polished surface, it will not stick to it as well as if the magnet had an anti-slip surface, such as a rubber coating. Because the layer of rubber on the rubber-coated magnet is slightly thicker than the nickel-plating layer itself, the magnet is further away from the supporting base, and the holding force also changes slightly.
equal lifting force (floor and ceiling)
the surface must be flat for a greater force
the surface must be thick for the magnet to have something to grip onto
How do we test magnetic force?
We test the magnetic force of magnets on a polished steel plate made of S235JR material with a minimum thickness of 10 mm, which is considered the best among commonly available steel grades. This way, we test the force of all magnets, except for load-bearing magnets, where we use thicker materials.
Experiment: Find the difference in magnetic force.
How can we better illustrate the difference between holding force and shearing force?
Attach a neodymium magnet to a refrigerator door.
a) Take the magnet in your hand and pull it away from the surface of the refrigerator towards yourself.
b) Reattach the magnet to the refrigerator. This time, simply move the magnet up or down the refrigerator door.
When did the magnet become easier to move?
As you can see, it's option b) because when sliding on smooth refrigerator doors, coated magnets do not hold as strongly. However, if a thin anti-slip foil were attached to the refrigerator, moving the magnet would be much more difficult. This also applies to other cases, not just with magnets. Sliding a full cardboard box on a smooth floor is much easier than on a shaggy-type carpet because the friction is much greater.
What does the lifting capacity in kilograms mean for a magnet?
The actual lifting capacity for magnetic holders (120 kg, 290 kg, 330 kg, 480 kg, etc.) indicates the breaking force for each magnet. It represents the maximum weight of items that the magnet can still hold.
The numbers may seem high, but they are measured under ideal conditions. During magnet fishing, finds are often rusty and only touch a small portion of the magnet. Underwater, there are also roots, rocks, and other obstacles that can cause the detachment of the find from the magnet. That's why the magnet needs to have a much greater force than the weight of the objects being pulled.
You can use magnets in many different ways at home. Magnetic holders can also serve as toys for children or as part of interior decorations. They can also be used for metal object retrieval, mounting advertisements or banners.
Usually, the magnet is protected by a relatively thin layer of nickel. Be cautious with it: if it gets damaged, you will likely need to purchase a new product soon.
If you want to use magnets in temperatures up to 450°C, opt for a different type of magnet, such as alnico. This way, you can ensure that your object doesn't lose its properties, and you can confidently use it even with heated machinery or in certain areas of a forge. This type of magnet typically contains iron, aluminum, nickel, and cobalt. They were first created in Japan in 1931 and are now commonly used in industries. They are used, for example, in motors or microphones.
Using magnetic holders is both convenient and eco-friendly. After all, a properly chosen and well-maintained holder will serve you effectively for many years. So don't rush with the purchase. Stick to trusted brands and read reviews before making a decision. Pay special attention to the housing's tightness and whether you will be using the magnet in a watery or highly humid environment. By following these guidelines, you will surely make a good choice!