Magnets are a staple of any welding shop. Whether you’re positioning pieces together for fusion or picking up stray shards of metal from around your workspace, having a magnet on hand can make many projects much simpler. A favorite among welders? The on/off magnet.
There are many unique benefits to being able to simply flip a switch and ‘turn off’ a magnetic field—but how do welding magnets with switches work exactly? All on/off magnets, or magnets with switches, are electromagnetic. This means an external electrical power source creates the magnetic field to magnetize the material. This allows the user to choose whether they want the magnet magnetized or not at any given moment.
Understanding how on/off magnets work, as well as their many benefits and applications in the world of welding, may help you see why they’re such a popular option among fabricators. See why adding an on/off welding magnet to your tool belt can help you better prepare for your next project.
How Do Magnets Work
In order to understand how magnets with switches work, first, it’s important to know how magnets themselves function. Magnets contain charged particles that can either attract or repel other charged particles and certain materials. All magnets work on attraction and repulsion—each has a south and north side. While opposite sides will attract each other, north will repel north and south will repel south.
There are two types of magnets: permanent magnets and electromagnets.
Permanent magnets are objects that contain charged particles, effectively producing their own magnetic fields. This field allows the object to attract and ‘stick’ to other magnetic objects or certain types of metals—ferromagnetic materials, to be exact.
Ferromagnetic materials include iron, nickel, cobalt, and others, all of which are highly attracted to magnetic pulls. Alloys containing ferromagnetic materials are also attracted to magnetic fields. These metals include certain types of steel, such as those containing iron or nickel. Magnets won’t, however, stick to metals not containing ferromagnetic material, such as aluminum, copper, lead, titanium, and gold among others.
Some permanent magnets are stronger than others—rare earth magnets, for example. However, no permanent magnet is truly ‘permanent,’ though the name may suggest otherwise. Various factors may serve to weaken the object’s magnetism, causing a weaker field and less attraction. Age is the most natural cause of loss of magnetism. Active atoms create a magnet’s magnetic field. Over time, they begin to rearrange themselves and move in such a way as to create a lesser magnetic pull. Intense impacts, heat, and exposure to other magnetic fields can also disrupt the magnet’s atoms, causing a decrease in magnetism.
The same basic principles apply to electromagnets with one exception: they do not create their own magnetic field. Rather, electricity passes through the material to create a magnetic field. While the metal is magnetized, it will present a north and south pole, just as with permanent magnets.
Electromagnets are comprised of a base metal, coils, and an electrical source to create the magnetic field, magnetizing the base metal—batteries are a common power source used in electromagnets. Electromagnets are used in a vast array of objects and industries, from the large machines used to haul old cars in scrapyards to the intricate mechanics behind a simple doorbell.
The strength of an electromagnet will vary based on two factors. The first is the number of coils around the core. The second is the amount of voltage passing through the coils. More coils result in stronger magnetism—likewise, higher voltage creates a more powerful magnetic field. You do not need to use the two in conjunction with one another to create a stronger pull. However, combining them will result in a much stronger magnetic field.
One major benefit to electromagnets is that you can effectively turn them ‘off’ by disrupting the current. When the electricity ceases to flow around the coils and magnetize the base metal, the magnet ceases to be a magnet. Consequently, all electromagnetic magnets are on/off magnets.
What Are On/Off Welding Magnets?
On/off welding magnets are electromagnets with a switch that allows the user to essentially turn the magnetic field ‘on’ or ‘off.’ When the magnet is ‘on,’ the object will act just like a permanent magnet would—attracting ferromagnetic materials. When the magnet is ‘off,’ all magnetism immediately disappears, and the object will act just like any other regular piece of metal.
Most on/off welding magnets contain iron cores wrapped in copper coils. The power source delivering electricity to the coils is typically a battery as it allows the user to move the magnet about freely and with fewer restrictions regarding the arc path. When you switch the magnet ‘on,’ electrical current will begin to flow through the coils and around the core, creating a magnetic field.
Magnets are useful for a variety of welding applications. The on/off capacity of an electromagnet opens up even more options for welders looking for the right tool for the project at hand.
Magnets can be a very useful tool when planning and preparing your next welding project. This practice is also commonly referred to as layout work. These tools allow fabricators to lay pieces out and join them as if they were welded to better plan for the final result. Essentially, magnets allow users to ‘test-run’ the pieces before, during, and after they’re cut and prepared for the welding process prior to fusion to ensure the best possible result.
It’s important to note that you must be careful when welding in the presence of a magnet. Welding arcs are powered by electricity—electromagnets are fueled by electricity. Consequently, welding too close to a strong magnetic field can distort the arc and cause major weld defects. As mentioned before, most on/off welding magnets get their power from batteries. This is because internally powered electromagnets tend to have less of an effect on the exposed welding arc that those with continuous external power sources.
Because magnets can distort a welding arc, magnets are most effectively used when tacking. Once the tacks are in place, remove the magnets and continue the welding process. This helps facilitate a better result free of the defects a magnetic field can cause.
Welding magnets are also commonly used to secure pieces of metal together so they are properly aligned when the times comes to fuse the materials. They are particularly useful when aiming to fuse pieces together at an angle that requires support until the weld is completed. Welding magnets come in a wide variety of shapes and sizes crafted to make even the trickiest welds a breeze. Be sure to compare the various dimensions and angles offered when deciding on the right magnet for your project.
Magnets, and especially electromagnets, are very useful when cleaning up around your welding station. Projects that require cutting, grinding, and other such activities often leave behind metal shavings. While some are noticeable or large enough for a broom to pick up, many are incredibly small and go unnoticed. While these tiny shards may seem insignificant, they can cause other problems down the road if not properly handled.
Is your welding station is at home or in a location where bare feet or paws may be passing through? Residual metal shards can cause serious injuries. The simple solution? Take your on/off magnet and place it in an inside-out baggie. Turn the magnet on and do a careful sweep of the entire area. Make sure to run the device over any areas where metal shavings may have landed. After you’ve covered the entire area, simply turn the baggie right-side in so the magnet sits on the exterior and the shavings are inside. Next, flip the switch off. Once the magnetic field is turned off, the shavings will detach from the device and be safely stored in the baggie.
Additionally, if your welding station frequently experiences any kind of moisture—as with a backyard welding set-up—residual shavings from metals like steel can result in unseemly rust stains. Using the cleaning trick outlined above can help you avoid the pain of a stained patio or the difficult process of cleaning rust off your backyard décor.
Making Your Own Electromagnet
If you’re looking to test out an electromagnet on a budget, you’re in luck—it is possible, and rather simple, to create a basic on/off magnet from relatively common household items. All you’ll need is one long iron nail, a dry cell battery, thinly coated copper wiring, and electric tape to hold it all together.
First, wrap the copper wire around the nail, being careful not to overlap layers. Make sure you leave enough of the wire on either side to attach to the battery (about 8 inches). Next, peel the coating off the ends of the copper wire. Wrap one end around the positive terminal of the battery and the other around the negative. Tape both sides down to ensure the wires don’t slip from the battery terminals and you have yourself an electromagnet. Grab a small iron-filled object, like a paperclip, to test out your newly formed magnet. The magnetic field will ‘turn off’ either when the battery dies or you disconnect the ends of the wire from their respective terminals.
Note that this magnet is very basic and may not be suitable for more demanding projects. Carefully research your project and compare different magnet offerings to help you determine the best option for your needs.
From preparation and welding to clean-up, it’s easy to see why electromagnets play such a large role in many welding projects. This useful tool is one that is here to stay. If you haven’t tried using an on/off magnet to vamp up your fabrication game yet, now is the time.