Magnetizer / Demagnetizer





Introduction: Magnetizer / Demagnetizer

Surely magnetized tools have helped you many times, the best example is definitely a screwdriver. When you drop the screw in inaccessible location you can easily pick it up with magnetized tip of screwdriver. Even if not magnetized, it is very easily done just by touching the strong permanent magnet. And what to do when this feature bothers you, when you work in a small space, and small bolts and nuts keep sticking to the screwdriver tip? Continue reading and find out how to make simple device that will help you solve both problems.

Complete construction procedure of device mentioned above, and on video is available on my site



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14 Discussions

How would you connect this with a bridge rectifier? The only way I can visualize is to get a double pole double throw switch (center off). I think you'd still be at 1/2 wave if you connect the AC Neutral and DC Neg together.

Well I did it worked for 2 secs then the coil overheated, coil was from a washing machine so don't know why it popped :(

I made a magnetizer for my eight grade science class (1978) building it completely from scratch using a short plank of wood (1" X 8") and two standing 1" X 3"s which were 4 3/4" high with a 1 3/4" hole cut into each piece a 1/2" from the top of each piece and centered. The holes were where I inserted a cardboard tube (I think it was a toilet paper tube to be exact) and the tube was wrapped from end to end with four layers of insulated copper wiring.

One end of the copper wiring fed out directly from the cardboard tube to a nail where one end of a power cord was also attached. Meaning: both wires attached at the same point...that being the nail, which was nailed into the top side of the board. There are three nails nailed into the top of the board all in alignment with each other and each all about an inch and a half apart from each other. The other power cord wire attaches to the next nail in the series so that both power cord wires basically split into a "Y" and attach to the two nails closest to each other.

The other insulated copper wire came out of the other end of the card board tube and was attached to the third nail in the series. This creates a gap between the last of the three nails between the wire attachments and also causes the circuit to be left open.

The reason for the gap is to create a space where you can attach a strip of tin foil. The tin foil acts as a fuse and keeps you from "melting" your insulated copper wire.

To start: MAKE SURE YOUR MAGNETIZER IS NOT PLUGGED IN! THIS COULD RESULT IN INJURY DUE TO ELECTROCUTION! This is a very safe experiment when following safety rules and common sense. ALWAYS WEAR SAFETY GLASSES!

At this point, you can place a thin, long metal object such as the end of a scissors, or a large nail or bolt, etc. into one end of the tube or an object made of steel or iron which you will be wanting to magnetize which will actually fit inside this thin tube. After placing the desired object into the tube...attach a 1/2" wide by 2" long strip of tin foil to both end points between the "FUSE" gap in order to complete the circuit.

Make sure you and anyone standing near the magnetizer are wearing safety glasses. This experiment should be conducted (if at home) in a garage or outside the garage. If at school...then in a science lab where safety protocols can be addressed. There will be a brief pop and sparks when you plug the power cord into a wall socket. The subsequent pop and sparks are supposed to happen. That is the fuse popping when the circuit is completed and all the electrons meet up face to face (so to speak). After the fuse has instantly popped...UNPLUG the power cord! Safety first!

Viola! You now have a magnetized scissors or other steel or iron object. Congratulations!


i found the weak link in my setup was the coil. i tried to make my coil using wire and the case from 1/2" thread seal tape i didnt count how many wraps i made but it must have been to many because when i started it up it pulled all metal within 8" around it to the actually worked to well. although it was cool to see in about 2 seconds of being turned on is melted the hot glue and the case. is was just wondering if anyone knew of a formula or something to make this coil to max power but not instantly overheat.

this was my first time ever experimenting with electronics. this was a simple project. It took me a total of 4 hours to make this including learning to solder , reviewing the schematic over and over to learn what way the diode went(then seen the pics), and also used a multimeter for the first time. i live in North America and i i got my coil from a microwave oven turntable 120v 60hz. the page said the switch was an SPCO( single pole change over) . i learned the switch is also called an SPDT( single pole dual toggle) i found this at an auto parts store, it make be called different things in different regions or something.Diode was the same and just used a cheap extension cord for the main line to plug to the wall. the case ended up being the hardest thing to make. overall i would say that damirvk did a very great job on making this instructable. thank you very much for the knowledge and moral boost.

1 reply

Makes me very glad that my post was so helpful.
Simple projects are best for learning, and this kind of comments are best reward for my effort.


Thanks for making this! I'd like to make one for myself, but I'm in the US. Would you recommend different component values for 120 V AC at 60 Hz?

2 replies

You should find coil designed for 120V and that is only thing that is different from my design.

I once used the core of a much larger old electric motor to erase cassette tapes. I had to be very careful to turn it "off" after just a couple of seconds, or it would draw too much current and overheat. What I really like about your design is the addition of the diode and the double throw switch so the device can be used to magnetize something, too. I have sometimes seen people wind insulated wire around a tool they wanted to magnetize and touch it briefly to the posts on an automobile battery. Again, the wires become quite warm after only a few seconds.

1 reply

Yes you are right about heating, especially in magnetizer mode when DC current is flowing through coil. That is the reason why I use small power coil. After 3-5min it gets warm and that is more than enough for normal use in workshop.