How long will a magnet retain its magnetic force? This is a question we get asked quite often and it surely is a valid request in its own right. Magnets can lose their magnetism to a certain extent. But how does that work exactly? We looked into it and will tell you all about it in this article.
Magnets play an important role in our modern-day lives. The concept of magnetism is applied to countless situations. Part of science and traffic would come to a standstill if it couldn’t rely on this phenomenon. Even the earth itself is an actual magnet. Does this mean that we have to fear magnets will quickly lose their magnetism? Not entirely.
How magnets lose their strength
In the world of magnetism, a distinction is made between two types of magnets: permanent magnets and electromagnets. Electromagnets depend on an electric current and can therefore be turned on and off. On the other hand, permanent variants are magnetic in and of themselves and cannot be switched off.
Several different raw materials can be used in the manufacturing process of permanent magnets. Neodymium is the strongest among these materials. Therefore, neodymium is commonly used to produce fishing magnets. Another possible raw material would be ferrite, which mostly finds its application in transformers.
Extreme high or low temperatures are detrimental to the functioning of magnets. At a temperature of about 175 degrees Fahrenheit (80° C) a neodymium fishing magnet will start losing its magnetic strength to a certain extent. Ferrite magnets are able to withstand much higher temperatures. They only start to suffer from a loss in magnetic strength at temperatures of over 356 degrees Fahrenheit (180°C). However, ferrite is much more vulnerable to low temperatures. A cold of minus -40 degrees Fahrenheit (-40°C) is already reducing the magnetic pulling strength.
Strong magnetic fields
Powerful magnetic fields create a hazard to permanent magnets. The full theory behind this concept is rather complicated. Neodymium magnets are especially vulnerable to strong magnetic fields created by electromagnets. They will start showing a loss of strength after prolonged exposure.
Ferrite magnets may also get weaker when they are in the vicinity of a magnetic field for longer periods. Such a field could even be caused by a neodymium magnet, as these kinds of magnets are usually stronger. Moreover, magnetic fields created by electromagnets can also form a threat to the power of ferrite magnets.
Shocks and impact
The strength of certain magnets could decrease as a result of shocks or the impact from hitting other objects. However, these kinds of shocks and impacts would need to be repetitive, otherwise it wouldn’t really affect magnetism. This is especially true for older magnets. Experts claim that recently produced quality magnets are more resistant to impacts. That’s not to say they can’t get damaged, as Neodymium magnets are still very brittle. As a consequence, neodymium magnets can easily be damaged physically. This might influence the magnetic strength of the magnet just as well.
How long can a fishing magnet remain magnetic?
High-end fishing magnets are all made of neodymium. For safety reasons, these fishing magnets are usually shielded with a stainless steel protective cover. This preserves the brittle character of neodymium. Additionally, magnet fishing doesn’t involve extremely high or low temperatures. Neither are there any strong magnetic fields out at the waterfront. Shocks and bumps are commonplace, but neither repetitive nor powerful. Water around the magnet will severely reduce any impact caused by objects in the water.
Magnet fishers need not worry about their magnets getting weaker. We learned from experience that with normal use of a permanent magnet made of neodymium or ferrite neither would lose its strength easily. This also applies to magnets that aren’t intended for magnet fishing or any other unusual hobby. Old(er) magnets lose their strength over time regardless. This is hardly avoidable. Yet, for quality neodymium magnets this process will only be noticeable after decades.
How long will a magnet retain its magnetic force? That depends on the circumstances and the type of magnet.