I am trying to demagnetize this vise grips.
They became magnetized because of repeated times that small magnets on my work bench stuck to the vise grips.
I tried the method where you hit it with a hammer, but it does not work.
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1I've heard that dropping your tool on a hard surface several times should reduce or eliminate the magnetism, but that could also damage (bend / warp) the vise grips and make them unusable.– BrettFromLAAug 4, 2019 at 14:10
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3@BrettFromLA These are made with high-grade heat-treated chrome molybdenum steel. You'd have to drop them onto an anvil from Burj Khalifa in Dubai and at that I think they still might work.– StanAug 4, 2019 at 16:08
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Why do you want to demagnetize this tool?– GdalyaAug 5, 2019 at 18:46
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@Gdalya Because it interferes with some operations. For example, I was pulling staples out of some wood and instead of those staples falling to the table, they stuck to the vise grips requiring me to physically remove them.– fixit7Aug 5, 2019 at 21:28
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@fixit7 A life-hacky way to accomplish this might be to wrap several layers of masking tape around the grips. This might move the item being gripped (e.g., staples) far enough away from the magnetized grip that they would no longer "stick" (due to the inverse square law).– GdalyaJul 2, 2020 at 12:51
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4 Answers
There are a few ways to destroy a magnet.
- By impact
Rough handling (dropping, hitting, etc.) a magnetized item can weaken it as well as creating one from iron bearing metal. That's how tools become magnetized in the first place. (Isn't that ironic?) Chances are that all of the handling was random so undoing it must not be random to be most efficient. You'll have the greatest success by using the Earth's magnetism to help you. To most efficiently magnetize an iron item, align it with the Earth's magnetic pole and strike it repeatedly. To demagnetize a magnetized item, align it crosswise to the isogonic lines running from the North Magnetic Pole to the South Magnetic Pole and do the same (strike it repeatedly) to mis-align the magnetic domains that have formed within the piece. Repeated blows are necessary — the force is less important than the number of blows or drops. Be patient and persistent. For example, you could rig a bell-ringer strike the piece until it was neutrally charged - By heat
If you can heat the jaws of the grips to their "Curie Point" the magnetism is lost. This varies with different materials. Vice Grips are made of heat-treated chrome molybdenum steel which require a little more than 880°C (2750°F) which will compromise the heat-treatment of the jaws. You could heat-treat the jaws again to harden them after the magnetism has been dissipated. - By induction
If the poles can be determined by using a compass, say, then another magnet can be fastened to the jaws in the same polarity as the jaws which will let them "fight it out" between them. They will gradually weaken each other to the point of failure. - By electricity
Placing the piece within a coil of wire running AC while it is aligned cross-wise to the Earth's isogonic lines (East to West) is another means to reduce the magnetism induced into a iron-bearing material. The fast reversals of current "shake up" the magnetic domains, as if in a cocktail shaker, randomizing them into misalignment (demagnetized condition). As the voltage is reduced to zero the magnetism is also diminished to zero. This was the means behind "demagnetizers" used to "erase" audio and video tapes for re-use of for security. It is the concept for magnetic hard disk drives.
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Placing the piece within a coil of wire running AC while it is aligned cross-wise to the Earth's isogonic lines (East to West)? I have used such a demag coil many times, and merely slowly pulling the magnetized object out of the demag coil (while paying no attention to how it was oriented) did the job.Are you certain that it needs to be so aligned to the earth's magnetic field? I never heard of this, do you have any references or anecdotal experiences? Aug 8, 2019 at 3:35 -
I have worked with old B&W television monitors - demagnetizing them - and noticed that the ones that were affected were facing one way. Those (I don't remember which direction specifically - NS I think) needed periodic demagnetizing. Gradually, the Earth's magnetism polarized the tube was the theory. It seemed to fit. Ones facing a different way didn't. Since then, TV sets with picture tubes (requiring deflection of electron beam to scan) were equipped with a coil built into the set that ran on power-up. Now, the practice is unnecessary and probably long-forgotten by most.– StanAug 8, 2019 at 13:49
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Beyond the great answer by Stan, there are actually a few tools that'll demagnetize things. Googling "demagnetizer" seemed to bring up a lot of good options, with a lot of places to get them, including the standard online, department, and home improvement stores.
You can demagnetize the tips of the jaws, but not the whole tool with this one.
You rub the tool on the outside of this block to demagnetize, if I remember correctly.
You can also get an electromagnet to do the same. The below is a random example that happens to demagnetize watches, but there's others out there, including ones that do old-school CRT TV screens.
I was able to demagnetize the vise grips by heating it up for about 5 minutes using a propane torch.
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How hot did you make it? Did you destroy metals hardness at the same time? Aug 26, 2019 at 18:02
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@James Jenkins It did not get red hot. I doubt the metal hardness got destroyed.– fixit7Aug 27, 2019 at 0:07
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Curie temperature is 1415 F ( demagnetizes) . That temp will certainly soften any carbon or low alloy steel used for hand tools . But depending on time, temperature, alloy , it may still have usable hardness. Sep 4, 2019 at 1:02
My father did it many years ago at home with old soldering gun that he always had at home. It was very easy:
- Put the item to be demagnetized far away from the soldering gun.
- Turn on the soldering gun
- Put the item as close as possible to the rear of the gun (not the hot part!) and keep it there.
- Very slowly move it away from the soldering gun
- Turn off the sondering gun
How it works: the rear part of the soldering gun creates a magnetic field of periodically changing polarity (it's under alternate current). As you slowly move the item away, it's magnetic field will be constantly oscillating with lesser and lesser amplitude, so it will basically converge to zero :-)
PS: the image is just for illustration (not our original soldering gun :))
